CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Uninterruptible power supply - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"f3bb326a-ed36-4f68-9769-3f5596acc3ff","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Uninterruptible_power_supply","wgTitle":"Uninterruptible power supply","wgCurRevisionId":1273691375,"wgRevisionId":1273691375,"wgArticleId":41834,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Webarchive template wayback links","All articles with dead external links","Articles with dead external links from June 2016","Articles with dead external links from May 2014","Articles with dead external links from July 2016","Articles with permanently dead external links","Articles with short description","Short description is different from Wikidata","Wikipedia articles needing clarification from May 2012","Articles to be expanded from December 2009", "All articles to be expanded","Commons category link from Wikidata","Uninterruptible power supply","Electric power systems components","Fault tolerance","Voltage stability"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Uninterruptible_power_supply","wgRelevantArticleId":41834,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":50000,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage", "wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q207696","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","site" ,"mediawiki.page.ready","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.16"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/f/f4/UPSFrontView.jpg"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="1622"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/UPSFrontView.jpg/800px-UPSFrontView.jpg"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="1081"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/UPSFrontView.jpg/640px-UPSFrontView.jpg"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="865"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Uninterruptible power supply - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Uninterruptible_power_supply"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Uninterruptible_power_supply&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Uninterruptible_power_supply"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Uninterruptible_power_supply rootpage-Uninterruptible_power_supply skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" title="Main menu" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li><li id="n-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages"><span>Special pages</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Uninterruptible+power+supply" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Uninterruptible+power+supply" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Uninterruptible+power+supply" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Uninterruptible+power+supply" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Common_power_problems" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Common_power_problems"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Common power problems</span> </div> </a> <ul id="toc-Common_power_problems-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Technologies" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Technologies"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Technologies</span> </div> </a> <button aria-controls="toc-Technologies-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Technologies subsection</span> </button> <ul id="toc-Technologies-sublist" class="vector-toc-list"> <li id="toc-Offline/standby" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Offline/standby"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Offline/standby</span> </div> </a> <ul id="toc-Offline/standby-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Line-interactive" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Line-interactive"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Line-interactive</span> </div> </a> <ul id="toc-Line-interactive-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Online/double-conversion" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Online/double-conversion"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Online/double-conversion</span> </div> </a> <ul id="toc-Online/double-conversion-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Other_designs" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Other_designs"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Other designs</span> </div> </a> <button aria-controls="toc-Other_designs-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Other designs subsection</span> </button> <ul id="toc-Other_designs-sublist" class="vector-toc-list"> <li id="toc-Hybrid_topology/double_conversion_on_demand" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Hybrid_topology/double_conversion_on_demand"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Hybrid topology/double conversion on demand</span> </div> </a> <ul id="toc-Hybrid_topology/double_conversion_on_demand-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Ferroresonant" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Ferroresonant"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Ferroresonant</span> </div> </a> <ul id="toc-Ferroresonant-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DC_power" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DC_power"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>DC power</span> </div> </a> <ul id="toc-DC_power-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Rotary" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Rotary"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Rotary</span> </div> </a> <ul id="toc-Rotary-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Form_factors" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Form_factors"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Form factors</span> </div> </a> <ul id="toc-Form_factors-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Applications" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Applications"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Applications</span> </div> </a> <button aria-controls="toc-Applications-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Applications subsection</span> </button> <ul id="toc-Applications-sublist" class="vector-toc-list"> <li id="toc-N_+_1" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#N_+_1"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span><i>N</i> + 1</span> </div> </a> <ul id="toc-N_+_1-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Multiple_redundancy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Multiple_redundancy"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Multiple redundancy</span> </div> </a> <ul id="toc-Multiple_redundancy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Outdoor_use" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Outdoor_use"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.3</span> <span>Outdoor use</span> </div> </a> <ul id="toc-Outdoor_use-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Harmonic_distortion" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Harmonic_distortion"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Harmonic distortion</span> </div> </a> <ul id="toc-Harmonic_distortion-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Power_factor" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Power_factor"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Power factor</span> </div> </a> <ul id="toc-Power_factor-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Communication" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Communication"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Communication</span> </div> </a> <ul id="toc-Communication-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Batteries" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Batteries"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Batteries</span> </div> </a> <button aria-controls="toc-Batteries-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Batteries subsection</span> </button> <ul id="toc-Batteries-sublist" class="vector-toc-list"> <li id="toc-Common_battery_characteristics_and_load_testing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Common_battery_characteristics_and_load_testing"> <div class="vector-toc-text"> <span class="vector-toc-numb">9.1</span> <span>Common battery characteristics and load testing</span> </div> </a> <ul id="toc-Common_battery_characteristics_and_load_testing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Testing_of_strings_of_batteries/cells" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Testing_of_strings_of_batteries/cells"> <div class="vector-toc-text"> <span class="vector-toc-numb">9.2</span> <span>Testing of strings of batteries/cells</span> </div> </a> <ul id="toc-Testing_of_strings_of_batteries/cells-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Series-parallel_battery_interactions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Series-parallel_battery_interactions"> <div class="vector-toc-text"> <span class="vector-toc-numb">9.3</span> <span>Series-parallel battery interactions</span> </div> </a> <ul id="toc-Series-parallel_battery_interactions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Series_new/old_battery_interactions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Series_new/old_battery_interactions"> <div class="vector-toc-text"> <span class="vector-toc-numb">9.4</span> <span>Series new/old battery interactions</span> </div> </a> <ul id="toc-Series_new/old_battery_interactions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Standards" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Standards"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Standards</span> </div> </a> <ul id="toc-Standards-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Uninterruptible power supply</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 48 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-48" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">48 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%88%D8%AD%D8%AF%D8%A9_%D8%B9%D8%AF%D9%85_%D8%A7%D9%86%D9%82%D8%B7%D8%A7%D8%B9_%D8%A7%D9%84%D8%AA%D8%BA%D8%B0%D9%8A%D8%A9" title="وحدة عدم انقطاع التغذية – Arabic" lang="ar" hreflang="ar" data-title="وحدة عدم انقطاع التغذية" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/K%C9%99silm%C9%99z_enerji_qayna%C4%9F%C4%B1" title="Kəsilməz enerji qaynağı – Azerbaijani" lang="az" hreflang="az" data-title="Kəsilməz enerji qaynağı" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%87%E0%A6%89%E0%A6%AA%E0%A6%BF%E0%A6%8F%E0%A6%B8" title="ইউপিএস – Bangla" lang="bn" hreflang="bn" data-title="ইউপিএস" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9D%D0%B5%D0%BF%D1%80%D0%B5%D0%BA%D1%8A%D1%81%D0%B2%D0%B0%D0%B5%D0%BC%D0%BE_%D0%B7%D0%B0%D1%85%D1%80%D0%B0%D0%BD%D0%B2%D0%B0%D0%BD%D0%B5" title="Непрекъсваемо захранване – Bulgarian" lang="bg" hreflang="bg" data-title="Непрекъсваемо захранване" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Neprekidno_napajanje" title="Neprekidno napajanje – Bosnian" lang="bs" hreflang="bs" data-title="Neprekidno napajanje" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Sistema_d%27alimentaci%C3%B3_ininterrompuda" title="Sistema d'alimentació ininterrompuda – Catalan" lang="ca" hreflang="ca" data-title="Sistema d'alimentació ininterrompuda" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Zdroj_nep%C5%99eru%C5%A1ovan%C3%A9ho_nap%C3%A1jen%C3%AD" title="Zdroj nepřerušovaného napájení – Czech" lang="cs" hreflang="cs" data-title="Zdroj nepřerušovaného napájení" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/N%C3%B8dstr%C3%B8msanl%C3%A6g" title="Nødstrømsanlæg – Danish" lang="da" hreflang="da" data-title="Nødstrømsanlæg" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Unterbrechungsfreie_Stromversorgung" title="Unterbrechungsfreie Stromversorgung – German" lang="de" hreflang="de" data-title="Unterbrechungsfreie Stromversorgung" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Puhvertoiteallikas" title="Puhvertoiteallikas – Estonian" lang="et" hreflang="et" data-title="Puhvertoiteallikas" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%91%CE%B4%CE%B9%CE%AC%CE%BB%CE%B5%CE%B9%CF%80%CF%84%CE%B7_%CE%A0%CE%B1%CF%81%CE%BF%CF%87%CE%AE_%CE%95%CE%BD%CE%AD%CF%81%CE%B3%CE%B5%CE%B9%CE%B1%CF%82" title="Αδιάλειπτη Παροχή Ενέργειας – Greek" lang="el" hreflang="el" data-title="Αδιάλειπτη Παροχή Ενέργειας" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Sistema_de_alimentaci%C3%B3n_ininterrumpida" title="Sistema de alimentación ininterrumpida – Spanish" lang="es" hreflang="es" data-title="Sistema de alimentación ininterrumpida" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Etenik_gabeko_elikatze-iturri" title="Etenik gabeko elikatze-iturri – Basque" lang="eu" hreflang="eu" data-title="Etenik gabeko elikatze-iturri" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%85%D9%86%D8%A8%D8%B9_%D8%AA%D8%BA%D8%B0%DB%8C%D9%87_%D8%A8%D8%AF%D9%88%D9%86_%D9%88%D9%82%D9%81%D9%87" title="منبع تغذیه بدون وقفه – Persian" lang="fa" hreflang="fa" data-title="منبع تغذیه بدون وقفه" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Alimentation_sans_interruption" title="Alimentation sans interruption – French" lang="fr" hreflang="fr" data-title="Alimentation sans interruption" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%AC%B4%EC%A0%95%EC%A0%84_%EC%A0%84%EC%9B%90_%EC%9E%A5%EC%B9%98" title="무정전 전원 장치 – Korean" lang="ko" hreflang="ko" data-title="무정전 전원 장치" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%85%E0%A4%AC%E0%A4%BE%E0%A4%A7%E0%A4%BF%E0%A4%A4_%E0%A4%B5%E0%A4%BF%E0%A4%A6%E0%A5%8D%E0%A4%AF%E0%A5%81%E0%A4%A4_%E0%A4%86%E0%A4%AA%E0%A5%82%E0%A4%B0%E0%A5%8D%E0%A4%A4%E0%A4%BF" title="अबाधित विद्युत आपूर्ति – Hindi" lang="hi" hreflang="hi" data-title="अबाधित विद्युत आपूर्ति" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Suplai_daya_bebas_gangguan" title="Suplai daya bebas gangguan – Indonesian" lang="id" hreflang="id" data-title="Suplai daya bebas gangguan" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Gruppo_di_continuit%C3%A0" title="Gruppo di continuità – Italian" lang="it" hreflang="it" data-title="Gruppo di continuità" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%90%D7%9C-%D7%A4%D7%A1%D7%A7" title="אל-פסק – Hebrew" lang="he" hreflang="he" data-title="אל-פסק" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Sz%C3%BCnetmentes_t%C3%A1pegys%C3%A9g" title="Szünetmentes tápegység – Hungarian" lang="hu" hreflang="hu" data-title="Szünetmentes tápegység" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%A3%D1%80%D0%B5%D0%B4_%D0%B7%D0%B0_%D0%BD%D0%B5%D0%BF%D1%80%D0%B5%D0%BA%D0%B8%D0%BD%D0%B0%D1%82%D0%BE_%D0%BD%D0%B0%D0%BF%D0%BE%D1%98%D1%83%D0%B2%D0%B0%D1%9A%D0%B5" title="Уред за непрекинато напојување – Macedonian" lang="mk" hreflang="mk" data-title="Уред за непрекинато напојување" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%85%E0%A4%A8%E0%A4%87%E0%A4%82%E0%A4%9F%E0%A4%B0%E0%A4%AA%E0%A5%8D%E0%A4%9F%E0%A5%87%E0%A4%A1_%E0%A4%AA%E0%A5%89%E0%A4%B5%E0%A4%B0_%E0%A4%B8%E0%A4%AA%E0%A5%8D%E0%A4%B2%E0%A4%BE%E0%A4%AF" title="अनइंटरप्टेड पॉवर सप्लाय – Marathi" lang="mr" hreflang="mr" data-title="अनइंटरप्टेड पॉवर सप्लाय" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Bekalan_tenaga_berterusan" title="Bekalan tenaga berterusan – Malay" lang="ms" hreflang="ms" data-title="Bekalan tenaga berterusan" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-min mw-list-item"><a href="https://min.wikipedia.org/wiki/Suplai_dayo_lapeh_gangguan" title="Suplai dayo lapeh gangguan – Minangkabau" lang="min" hreflang="min" data-title="Suplai dayo lapeh gangguan" data-language-autonym="Minangkabau" data-language-local-name="Minangkabau" class="interlanguage-link-target"><span>Minangkabau</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%A2%D0%BE%D0%B3_%D0%B1%D0%B0%D1%80%D0%B8%D0%B3%D1%87" title="Тог баригч – Mongolian" lang="mn" hreflang="mn" data-title="Тог баригч" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%A1%E1%80%84%E1%80%BA%E1%80%97%E1%80%AC%E1%80%90%E1%80%AC" title="အင်ဗာတာ – Burmese" lang="my" hreflang="my" data-title="အင်ဗာတာ" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Noodstroomvoeding" title="Noodstroomvoeding – Dutch" lang="nl" hreflang="nl" data-title="Noodstroomvoeding" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ne mw-list-item"><a href="https://ne.wikipedia.org/wiki/%E0%A4%85%E0%A4%B5%E0%A4%BF%E0%A4%9A%E0%A5%8D%E0%A4%9B%E0%A4%BF%E0%A4%A8%E0%A5%8D%E0%A4%A8_%E0%A4%B5%E0%A4%BF%E0%A4%A6%E0%A5%8D%E0%A4%AF%E0%A5%81%E0%A4%A4_%E0%A4%86%E0%A4%AA%E0%A5%81%E0%A4%B0%E0%A5%8D%E0%A4%A4%E0%A5%80" title="अविच्छिन्न विद्युत आपुर्ती – Nepali" lang="ne" hreflang="ne" data-title="अविच्छिन्न विद्युत आपुर्ती" data-language-autonym="नेपाली" data-language-local-name="Nepali" class="interlanguage-link-target"><span>नेपाली</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E7%84%A1%E5%81%9C%E9%9B%BB%E9%9B%BB%E6%BA%90%E8%A3%85%E7%BD%AE" title="無停電電源装置 – Japanese" lang="ja" hreflang="ja" data-title="無停電電源装置" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Avbruddsfri_str%C3%B8mforsyning" title="Avbruddsfri strømforsyning – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Avbruddsfri strømforsyning" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%AF%E0%A9%82.%E0%A8%AA%E0%A9%80.%E0%A8%85%E0%A9%88%E0%A8%B8" title="ਯੂ.ਪੀ.ਅੈਸ – Punjabi" lang="pa" hreflang="pa" data-title="ਯੂ.ਪੀ.ਅੈਸ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%DB%8C%D9%88%DB%94%D9%BE%DB%8C%DB%94%D8%A7%DB%8C%D8%B3" title="یو۔پی۔ایس – Western Punjabi" lang="pnb" hreflang="pnb" data-title="یو۔پی۔ایس" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Zasilacz_awaryjny" title="Zasilacz awaryjny – Polish" lang="pl" hreflang="pl" data-title="Zasilacz awaryjny" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Fonte_de_alimenta%C3%A7%C3%A3o_ininterrupta" title="Fonte de alimentação ininterrupta – Portuguese" lang="pt" hreflang="pt" data-title="Fonte de alimentação ininterrupta" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Surs%C4%83_de_alimentare_ne%C3%AEntreruptibil%C4%83" title="Sursă de alimentare neîntreruptibilă – Romanian" lang="ro" hreflang="ro" data-title="Sursă de alimentare neîntreruptibilă" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%98%D1%81%D1%82%D0%BE%D1%87%D0%BD%D0%B8%D0%BA_%D0%B1%D0%B5%D1%81%D0%BF%D0%B5%D1%80%D0%B5%D0%B1%D0%BE%D0%B9%D0%BD%D0%BE%D0%B3%D0%BE_%D1%8D%D0%BB%D0%B5%D0%BA%D1%82%D1%80%D0%BE%D0%BF%D0%B8%D1%82%D0%B0%D0%BD%D0%B8%D1%8F" title="Источник бесперебойного электропитания – Russian" lang="ru" hreflang="ru" data-title="Источник бесперебойного электропитания" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Uninterruptible_power_supply" title="Uninterruptible power supply – Simple English" lang="en-simple" hreflang="en-simple" data-title="Uninterruptible power supply" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Zdroj_nepreru%C5%A1ovan%C3%A9ho_nap%C3%A1jania" title="Zdroj neprerušovaného napájania – Slovak" lang="sk" hreflang="sk" data-title="Zdroj neprerušovaného napájania" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%9D%D0%B5%D0%BF%D1%80%D0%B5%D0%BA%D0%B8%D0%B4%D0%BD%D0%BE_%D0%BD%D0%B0%D0%BF%D0%B0%D1%98%D0%B0%D1%9A%D0%B5" title="Непрекидно напајање – Serbian" lang="sr" hreflang="sr" data-title="Непрекидно напајање" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Keskeytym%C3%A4t%C3%B6n_virransy%C3%B6tt%C3%B6" title="Keskeytymätön virransyöttö – Finnish" lang="fi" hreflang="fi" data-title="Keskeytymätön virransyöttö" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Avbrottsfri_kraftf%C3%B6rs%C3%B6rjning" title="Avbrottsfri kraftförsörjning – Swedish" lang="sv" hreflang="sv" data-title="Avbrottsfri kraftförsörjning" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%A4%E0%AE%9F%E0%AE%99%E0%AF%8D%E0%AE%95%E0%AE%B2%E0%AF%8D_%E0%AE%87%E0%AE%B2%E0%AF%8D%E0%AE%B2%E0%AE%BE_%E0%AE%86%E0%AE%B1%E0%AF%8D%E0%AE%B1%E0%AE%B2%E0%AF%8D_%E0%AE%B5%E0%AE%B4%E0%AE%99%E0%AF%8D%E0%AE%95%E0%AE%BF" title="தடங்கல் இல்லா ஆற்றல் வழங்கி – Tamil" lang="ta" hreflang="ta" data-title="தடங்கல் இல்லா ஆற்றல் வழங்கி" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B9%80%E0%B8%84%E0%B8%A3%E0%B8%B7%E0%B9%88%E0%B8%AD%E0%B8%87%E0%B8%AA%E0%B8%B3%E0%B8%A3%E0%B8%AD%E0%B8%87%E0%B9%84%E0%B8%9F%E0%B8%9F%E0%B9%89%E0%B8%B2%E0%B9%81%E0%B8%A5%E0%B8%B0%E0%B8%9B%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B9%81%E0%B8%A3%E0%B8%87%E0%B8%94%E0%B8%B1%E0%B8%99%E0%B9%84%E0%B8%9F%E0%B8%9F%E0%B9%89%E0%B8%B2%E0%B8%AD%E0%B8%B1%E0%B8%95%E0%B9%82%E0%B8%99%E0%B8%A1%E0%B8%B1%E0%B8%95%E0%B8%B4" title="เครื่องสำรองไฟฟ้าและปรับแรงดันไฟฟ้าอัตโนมัติ – Thai" lang="th" hreflang="th" data-title="เครื่องสำรองไฟฟ้าและปรับแรงดันไฟฟ้าอัตโนมัติ" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Kesintisiz_g%C3%BC%C3%A7_kayna%C4%9F%C4%B1" title="Kesintisiz güç kaynağı – Turkish" lang="tr" hreflang="tr" data-title="Kesintisiz güç kaynağı" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%94%D0%B6%D0%B5%D1%80%D0%B5%D0%BB%D0%BE_%D0%B1%D0%B5%D0%B7%D0%BF%D0%B5%D1%80%D0%B5%D0%B1%D1%96%D0%B9%D0%BD%D0%BE%D0%B3%D0%BE_%D0%B6%D0%B8%D0%B2%D0%BB%D0%B5%D0%BD%D0%BD%D1%8F" title="Джерело безперебійного живлення – Ukrainian" lang="uk" hreflang="uk" data-title="Джерело безперебійного живлення" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/UPS" title="UPS – Vietnamese" lang="vi" hreflang="vi" data-title="UPS" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E4%B8%8D%E9%97%B4%E6%96%AD%E7%94%B5%E6%BA%90" title="不间断电源 – Chinese" lang="zh" hreflang="zh" data-title="不间断电源" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q207696#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Uninterruptible_power_supply" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Uninterruptible_power_supply" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Uninterruptible_power_supply"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Uninterruptible_power_supply"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Uninterruptible_power_supply" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Uninterruptible_power_supply" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&oldid=1273691375" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Uninterruptible_power_supply&id=1273691375&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FUninterruptible_power_supply"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FUninterruptible_power_supply"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Uninterruptible_power_supply&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Uninterruptible_power_supply&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Uninterruptible_power_supply" hreflang="en"><span>Wikimedia Commons</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q207696" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Electrical device that uses batteries to prevent any interruption of power flow</div> <style data-mw-deduplicate="TemplateStyles:r1273380762/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner span:not(.skin-invert-image):not(.skin-invert):not(.bg-transparent) img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner span:not(.skin-invert-image):not(.skin-invert):not(.bg-transparent) img{background-color:white}}</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:318px;max-width:318px"><div class="trow"><div class="tsingle" style="width:178px;max-width:178px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:UPSFrontView.jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f4/UPSFrontView.jpg/176px-UPSFrontView.jpg" decoding="async" width="176" height="238" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f4/UPSFrontView.jpg/264px-UPSFrontView.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f4/UPSFrontView.jpg/352px-UPSFrontView.jpg 2x" data-file-width="921" data-file-height="1245" /></a></span></div></div><div class="tsingle" style="width:136px;max-width:136px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:UPSRearView.jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/20/UPSRearView.jpg/134px-UPSRearView.jpg" decoding="async" width="134" height="238" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/20/UPSRearView.jpg/201px-UPSRearView.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/20/UPSRearView.jpg/268px-UPSRearView.jpg 2x" data-file-width="913" data-file-height="1621" /></a></span></div></div></div><div class="trow" style="display:flex"><div class="thumbcaption">A tower type UPS with one <a href="/wiki/IEC_60320" title="IEC 60320">IEC 60320</a> <a href="/wiki/IEC_60320#C13/C14_coupler" title="IEC 60320">C14</a> input and three <a href="/wiki/IEC_60320#C13/C14_coupler" title="IEC 60320">C13</a> outlets</div></div></div></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:500kVA-UPS.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5e/500kVA-UPS.jpg/220px-500kVA-UPS.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5e/500kVA-UPS.jpg/330px-500kVA-UPS.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5e/500kVA-UPS.jpg/440px-500kVA-UPS.jpg 2x" data-file-width="800" data-file-height="600" /></a><figcaption>A large data-center-scale UPS being installed by electricians</figcaption></figure> <p>An <b>uninterruptible power supply</b> (<b>UPS</b>) or <b>uninterruptible power source</b> is a type of <a href="/wiki/Continual_power_system" title="Continual power system">continual power system</a> that provides automated backup <a href="/wiki/Electric_power" title="Electric power">electric power</a> to a <a href="/wiki/Electrical_load" title="Electrical load">load</a> when the input power source or <a href="/wiki/Mains_electricity" title="Mains electricity">mains power</a> fails. A UPS differs from a traditional <a href="/wiki/Auxiliary_power" title="Auxiliary power">auxiliary</a>/<a href="/wiki/Emergency_power_system" title="Emergency power system">emergency power system</a> or <a href="/wiki/Standby_generator" title="Standby generator">standby generator</a> in that it will provide near-instantaneous protection from input power interruptions by switching to energy stored in <a href="/wiki/Battery_pack" title="Battery pack">battery packs</a>, <a href="/wiki/Supercapacitor" title="Supercapacitor">supercapacitors</a> or <a href="/wiki/Flywheel" title="Flywheel">flywheels</a>. The on-battery run-times of most UPSs are relatively short (only a few minutes) but sufficient to "buy time" for initiating a standby power source or properly shutting down the protected equipment. Almost all UPSs also contain integrated <a href="/wiki/Surge_protection" class="mw-redirect" title="Surge protection">surge protection</a> to shield the output appliances from <a href="/wiki/Voltage_spike" title="Voltage spike">voltage spikes</a>. </p><p>A UPS is typically used to protect hardware such as <a href="/wiki/Computer" title="Computer">computers</a>, hospital equipment, <a href="/wiki/Data_center" title="Data center">data centers</a>, <a href="/wiki/Telecommunications_equipment" title="Telecommunications equipment">telecommunications equipment</a> or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption or <a href="/wiki/Data_loss" title="Data loss">data loss</a>. UPS units range in size from ones designed to protect a single computer (around 200 <a href="/wiki/Volt-ampere" title="Volt-ampere">volt-ampere</a> rating) to large units powering entire data centers or buildings. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Common_power_problems">Common power problems</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=1" title="Edit section: Common power problems"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The primary role of any UPS is to provide short-term power when the input power source fails. However, most UPS units are also capable in varying degrees of correcting common utility power problems: </p> <ol><li><a href="/wiki/Voltage_spike" title="Voltage spike">Voltage spike</a> or sustained <a href="/wiki/Overvoltage" title="Overvoltage">overvoltage</a></li> <li>Momentary or sustained <a href="/wiki/Brownout_(electricity)" title="Brownout (electricity)">reduction in input voltage</a></li> <li><a href="/wiki/Voltage_sag" title="Voltage sag">Voltage sag</a></li> <li>Noise, defined as a <a href="/wiki/Line_noise" class="mw-redirect" title="Line noise">high frequency transient</a> or <a href="/wiki/Transient_(oscillation)" class="mw-redirect" title="Transient (oscillation)">oscillation</a>, usually injected into the line by nearby equipment</li> <li>Instability of the <a href="/wiki/Mains_frequency" class="mw-redirect" title="Mains frequency">mains frequency</a></li> <li><a href="/wiki/Harmonic_distortion" class="mw-redirect" title="Harmonic distortion">Harmonic distortion</a>, defined as a departure from the ideal <a href="/wiki/Sinusoidal" class="mw-redirect" title="Sinusoidal">sinusoidal</a> <a href="/wiki/Waveform" title="Waveform">waveform</a> expected on the line</li></ol> <p>Some manufacturers of UPS units categorize their products in accordance with the number of power-related problems they address.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>A UPS unit may also introduce problems with <a href="/wiki/Electric_power_quality" title="Electric power quality">electric power quality</a>. To prevent this, a UPS should be selected not only by capacity but also by the quality of power that is required by the equipment that is being supplied. </p> <div class="mw-heading mw-heading2"><h2 id="Technologies">Technologies</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=2" title="Edit section: Technologies"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The three general categories of modern UPS systems are <i>on-line</i>, <i>line-interactive</i> and <i>standby</i>:<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <ul><li>An online UPS uses a "double conversion" method of accepting AC input, <a href="/wiki/Rectifier" title="Rectifier">rectifying</a> to DC for passing through the <a href="/wiki/Rechargeable_battery" title="Rechargeable battery">rechargeable battery</a> (or battery strings), then inverting back to 120 V/230 V AC for powering the protected equipment.</li> <li>A line-interactive UPS maintains the inverter in line and redirects the battery's DC current path from the normal charging mode to supplying current when power is lost.</li> <li>In a standby ("off-line") system the load is powered directly by the input power and the backup power circuitry is only invoked when the utility power fails.</li></ul> <p>Most UPS below one kilo<a href="/wiki/Volt-ampere" title="Volt-ampere">volt-ampere</a> (1 kVA) are of the line-interactive or standby variety which are usually less expensive. </p><p>For large power units, dynamic uninterruptible power supplies (DUPS) are sometimes used. A synchronous motor/alternator is connected on the mains via a <a href="/wiki/Choke_(electronics)" title="Choke (electronics)">choke</a>. Energy is stored in a <a href="/wiki/Flywheel" title="Flywheel">flywheel</a>. When the mains power fails, an eddy-current regulation maintains the power on the load as long as the flywheel's energy is not exhausted. DUPS are sometimes combined or integrated with a diesel generator that is turned on after a brief delay, forming a <a href="/wiki/Diesel_rotary_uninterruptible_power_supply" title="Diesel rotary uninterruptible power supply">diesel rotary uninterruptible power supply</a> (DRUPS). </p> <div class="mw-heading mw-heading3"><h3 id="Offline/standby"><span id="Offline.2Fstandby"></span>Offline/standby</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=3" title="Edit section: Offline/standby"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Standby_UPS_Diagram_SVG.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/66/Standby_UPS_Diagram_SVG.svg/350px-Standby_UPS_Diagram_SVG.svg.png" decoding="async" width="350" height="350" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/66/Standby_UPS_Diagram_SVG.svg/525px-Standby_UPS_Diagram_SVG.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/66/Standby_UPS_Diagram_SVG.svg/700px-Standby_UPS_Diagram_SVG.svg.png 2x" data-file-width="1000" data-file-height="1000" /></a><figcaption>Offline/standby UPS: The green line illustrates the flow of electric power. Typical protection time: 5–20 minutes. Capacity expansion: Usually not available.</figcaption></figure> <p>The offline/standby UPS offers only the most basic features, providing surge protection and battery backup. The protected equipment is normally connected directly to incoming utility power. When the incoming voltage falls below or rises above a predetermined level the UPS turns on its internal DC-AC inverter circuitry, which is powered from an internal storage battery. The UPS then mechanically switches the connected equipment onto its DC-AC inverter output. The switch-over time can be as long as 25 milliseconds depending on the amount of time it takes the standby UPS to detect the lost utility voltage. The UPS will be designed to power certain equipment, such as a personal computer, without any objectionable dip or <a href="/wiki/Brownout_(electricity)" title="Brownout (electricity)">brownout</a> to that device. </p> <div class="mw-heading mw-heading3"><h3 id="Line-interactive">Line-interactive</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=4" title="Edit section: Line-interactive"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Line-Interactive_UPS_Diagram_SVG.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/24/Line-Interactive_UPS_Diagram_SVG.svg/500px-Line-Interactive_UPS_Diagram_SVG.svg.png" decoding="async" width="500" height="250" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/24/Line-Interactive_UPS_Diagram_SVG.svg/750px-Line-Interactive_UPS_Diagram_SVG.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/24/Line-Interactive_UPS_Diagram_SVG.svg/1000px-Line-Interactive_UPS_Diagram_SVG.svg.png 2x" data-file-width="2000" data-file-height="1000" /></a><figcaption>Line-interactive UPS: The green line illustrates the flow of electric power. Typical protection time: 5–30 minutes. Capacity expansion: several hours.</figcaption></figure> <p>The line-interactive UPS is similar in operation to a standby UPS but with the addition of a multi-tap variable-voltage <a href="/wiki/Autotransformer" title="Autotransformer">autotransformer</a>. This is a special type of <a href="/wiki/Transformer" title="Transformer">transformer</a> that can add or subtract powered coils of wire, thereby increasing or decreasing the magnetic field and the output voltage of the transformer. This may also be performed by a <i><a href="/wiki/Buck%E2%80%93boost_transformer" title="Buck–boost transformer">buck–boost transformer</a></i> which is distinct from an autotransformer, since the former may be wired to provide <a href="/wiki/Galvanic_isolation" title="Galvanic isolation">galvanic isolation</a>. </p><p>This type of UPS is able to tolerate continuous undervoltage <a href="/wiki/Brownout_(electricity)" title="Brownout (electricity)">brownouts</a> and overvoltage surges without consuming the limited reserve battery power. It instead compensates by automatically selecting different power taps on the autotransformer. Depending on the design, changing the autotransformer tap can cause a very brief output power disruption,<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> which may cause UPSs equipped with a power-loss alarm to "chirp" for a moment. </p><p>This has become popular even in the cheapest UPSes because it takes advantage of components already included. The main 50/60 Hz transformer used to convert between line voltage and battery voltage needs to provide two slightly different turns ratios: One to convert the battery output voltage (typically a multiple of 12 V) to line voltage, and a second one to convert the line voltage to a slightly higher battery charging voltage (such as a multiple of 14 V). The difference between the two voltages is because charging a battery requires a delta voltage (up to 13–14 V for charging a 12 V battery). Furthermore, it is easier to do the switching on the line-voltage side of the transformer because of the lower currents on that side. </p><p>To gain the <i>buck/boost</i> feature, all that is required is two separate switches so that the AC input can be connected to one of the two primary taps, while the load is connected to the other, thus using the main transformer's primary windings as an autotransformer. The battery can still be charged while "bucking" an overvoltage, but while "boosting" an undervoltage, the transformer output is too low to charge the batteries. </p><p>Autotransformers can be engineered to cover a wide range of varying input voltages, but this requires more taps and increases complexity, as well as the expense of the UPS. It is common for the autotransformer to cover a range only from about 90 V to 140 V for 120 V power, and then switch to battery if the voltage goes much higher or lower than that range. </p><p>In low-voltage conditions the UPS will use more current than normal, so it may need a higher current circuit than a normal device. For example, to power a 1000 W device at 120 V, the UPS will draw 8.33 A. If a brownout occurs and the voltage drops to 100 V, the UPS will draw 10 A to compensate. This also works in reverse, so that in an overvoltage condition, the UPS will need less current. </p> <div class="mw-heading mw-heading3"><h3 id="Online/double-conversion"><span id="Online.2Fdouble-conversion"></span>Online/double-conversion</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=5" title="Edit section: Online/double-conversion"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In an online UPS, the batteries are always connected to the inverter, so that no power transfer switches are necessary. When power loss occurs, the rectifier simply drops out of the circuit and the batteries keep the power steady and unchanged. When power is restored, the rectifier resumes carrying most of the load and begins charging the batteries, though the charging current may be limited to prevent the high-power rectifier from damaging the batteries. The main advantage of an online UPS is its ability to provide an "electrical firewall" between the incoming utility power and sensitive electronic equipment. </p><p>The online UPS is ideal for environments where electrical isolation is necessary or for equipment that is very sensitive to power fluctuations.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> Although it was at one time reserved for very large installations of 10 kW or more, advances in technology have now permitted it to be available as a common consumer device, supplying 500 W or less. The online UPS may be necessary when the power environment is "noisy", when utility power sags, outages and other anomalies are frequent, when protection of sensitive IT equipment loads is required, or when operation from an extended-run backup generator is necessary. </p><p>The basic technology of the online UPS is the same as in a standby or line-interactive UPS. However, it typically costs much more, due to it having a much greater current AC-to-DC battery-charger/rectifier, and with the <a href="/wiki/Rectifier" title="Rectifier">rectifier</a> and inverter designed to run continuously with improved cooling systems. It is called a <i>double-conversion</i> UPS due to the rectifier directly driving the inverter, even when powered from normal AC current. </p><p>Online UPS typically has a static transfer switch (STS) for increasing reliability. </p> <div class="mw-heading mw-heading2"><h2 id="Other_designs">Other designs</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=6" title="Edit section: Other designs"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Hybrid_topology/double_conversion_on_demand"><span id="Hybrid_topology.2Fdouble_conversion_on_demand"></span>Hybrid topology/double conversion on demand</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=7" title="Edit section: Hybrid topology/double conversion on demand"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>These hybrid rotary UPS<sup id="cite_ref-Rotary_UPS_7-0" class="reference"><a href="#cite_note-Rotary_UPS-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> designs do not have official designations, although one name used by UTL is "double conversion on demand".<sup id="cite_ref-HPman_8-0" class="reference"><a href="#cite_note-HPman-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> This style of UPS is targeted towards high-efficiency applications while still maintaining the features and protection level offered by double conversion. </p><p>A hybrid (double conversion on demand) UPS operates as an off-line/standby UPS when power conditions are within a certain preset window. This allows the UPS to achieve very high efficiency ratings. When the power conditions fluctuate outside of the predefined windows, the UPS switches to online/double-conversion operation.<sup id="cite_ref-HPman_8-1" class="reference"><a href="#cite_note-HPman-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> In double-conversion mode the UPS can adjust for voltage variations without having to use battery power, can filter out line noise and control frequency. </p> <div class="mw-heading mw-heading3"><h3 id="Ferroresonant">Ferroresonant</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=8" title="Edit section: Ferroresonant"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Ferroresonant units operate in the same way as a standby UPS unit; however, they are online with the exception that a <a href="/wiki/Voltage_regulator#Constant-voltage_transformer" title="Voltage regulator">ferroresonant transformer</a>, is used to filter the output. This transformer is designed to hold energy long enough to cover the time between switching from line power to battery power and effectively eliminates the transfer time. Many ferroresonant UPSs are 82–88% efficient (AC/DC-AC) and offer excellent isolation. </p><p>The transformer has three windings, one for ordinary mains power, the second for rectified battery power, and the third for output AC power to the load. </p><p>This once was the dominant type of UPS and is limited to around the <span class="nowrap">150 kVA</span> range. These units are still mainly used in some industrial settings (oil and gas, petrochemical, chemical, utility, and heavy industry markets) due to the robust nature of the UPS. Many ferroresonant UPSs utilizing controlled ferro technology may interact with power-factor-correcting equipment. This will result in fluctuating output voltage of the UPS, but may be corrected by reducing the load levels or adding other linear type loads.<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="The text near this tag needs further explanation. (May 2012)">further explanation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="DC_power">DC power</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=9" title="Edit section: DC power"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A UPS designed for powering DC equipment is very similar to an online UPS, except that it does not need an output inverter. Also, if the UPS's battery voltage is matched with the voltage the device needs, the device's <a href="/wiki/Power_supply" title="Power supply">power supply</a> will not be needed either. Since one or more power conversion steps are eliminated, this increases efficiency and run time. </p><p>Many systems used in telecommunications use an <a href="/wiki/Extra-low_voltage" title="Extra-low voltage">extra-low voltage</a> "<a href="/wiki/Common_battery" title="Common battery">common battery</a>" 48 V DC power, because it has less restrictive safety regulations, such as being installed in conduit and junction boxes. DC has typically been the dominant power source for telecommunications, and AC has typically been the dominant source for computers and servers. </p><p>There has been much experimentation with 48 V DC power for computer servers, in the hope of reducing the likelihood of failure and the cost of equipment. However, to supply the same amount of power, the current would be higher than an equivalent 115 V or 230 V circuit; greater current requires larger conductors or more energy lost as heat. </p><p>High voltage DC (380 V) is finding use in some data center applications and allows for small power conductors, but is subject to the more complex electrical code rules for safe containment of high voltages.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p><p>For lower power devices that run on 5 V, some <a href="/wiki/Battery_charger#Power_bank" title="Battery charger">portable battery banks</a> can work as a UPS. </p> <div class="mw-heading mw-heading3"><h3 id="Rotary">Rotary</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=10" title="Edit section: Rotary"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A rotary UPS uses the inertia of a high-mass spinning <a href="/wiki/Flywheel" title="Flywheel">flywheel</a> (<a href="/wiki/Flywheel_energy_storage" title="Flywheel energy storage">flywheel energy storage</a>) to provide short-term <a href="/wiki/Ride-through" class="mw-redirect" title="Ride-through">ride-through</a> in the event of power loss. The flywheel also acts as a buffer against power spikes and sags, since such short-term power events are not able to appreciably affect the rotational speed of the high-mass flywheel. It is also one of the oldest designs, predating vacuum tubes and integrated circuits. </p><p>It can be considered to be <i>on line</i> since it spins continuously under normal conditions. However, unlike a battery-based UPS, flywheel-based UPS systems typically provide 10 to 20 seconds of protection before the flywheel has slowed and power output stops.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> It is traditionally used in conjunction with standby generators, providing backup power only for the brief period of time the engine needs to start running and stabilize its output. </p><p>The rotary UPS is generally reserved for applications needing more than 10,000 W of protection, to justify the expense and benefit from the advantages rotary UPS systems bring. A larger flywheel or multiple flywheels operating in parallel will increase the reserve running time or capacity. </p><p>Because the flywheels are a mechanical power source, it is not necessary to use an electric motor or generator as an intermediary between it and a diesel engine designed to provide emergency power. By using a transmission gearbox, the rotational inertia of the flywheel can be used to directly start up a diesel engine,<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> and once running, the diesel engine can be used to directly spin the flywheel. Multiple flywheels can likewise be connected in parallel through mechanical <a href="/wiki/Countershaft" class="mw-redirect" title="Countershaft">countershafts</a>, without the need for separate motors and generators for each flywheel. </p><p>They are normally designed to provide very high current output compared to a purely electronic UPS, and are better able to provide inrush current for inductive loads such as motor startup or compressor loads, as well as medical MRI and <a href="/wiki/Cath_lab" class="mw-redirect" title="Cath lab">cath lab</a> equipment. It is also able to tolerate short-circuit conditions up to 17 times larger than an electronic UPS, permitting one device to blow a fuse and fail while other devices still continue to be powered from the rotary UPS. </p><p>Its life cycle is usually far greater than a purely electronic UPS, up to 30 years or more. But they do require periodic downtime for mechanical maintenance, such as <a href="/wiki/Ball_bearing" title="Ball bearing">ball bearing</a> replacement. In larger systems, redundancy of the system ensures the availability of processes during this maintenance. Battery-based designs do not require downtime if the batteries can be <a href="/wiki/Hot_swapping" title="Hot swapping">hot-swapped</a>, which is usually the case for larger units. Newer rotary units use technologies such as <a href="/wiki/Magnetic_bearing" title="Magnetic bearing">magnetic bearings</a> and air-evacuated enclosures to increase standby efficiency and reduce maintenance to very low levels. </p><p>Typically, the high-mass flywheel is used in conjunction with a <a href="/wiki/Motor-generator" class="mw-redirect" title="Motor-generator">motor-generator</a> system. These units can be configured as: </p> <ol><li>A motor driving a mechanically connected generator,<sup id="cite_ref-Rotary_UPS_7-1" class="reference"><a href="#cite_note-Rotary_UPS-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li>A combined <a href="/wiki/Synchronous_motor" title="Synchronous motor">synchronous motor</a> and generator wound in alternating slots of a single rotor and stator,</li> <li>A hybrid rotary UPS, designed similar to an online UPS, except that it uses the flywheel in place of batteries. The rectifier drives a motor to spin the flywheel, while a generator uses the flywheel to power the inverter.</li></ol> <p>In case No. 3, the motor generator can be synchronous/synchronous or induction/synchronous. The motor side of the unit in case Nos. 2 and 3 can be driven directly by an AC power source (typically when in inverter bypass), a 6-step double-conversion motor drive, or a 6-pulse inverter. Case No. 1 uses an integrated flywheel as a short-term energy source instead of batteries to allow time for external, electrically coupled gensets to start and be brought online. Case Nos. 2 and 3 can use batteries or a free-standing electrically coupled flywheel as the short-term energy source. </p> <div class="mw-heading mw-heading2"><h2 id="Form_factors">Form factors</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=11" title="Edit section: Form factors"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1273380762/mw-parser-output/.tmulti"> <p>Smaller UPS systems come in several different forms and sizes. However, the two most common forms are tower and rack-mount.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>Tower models stand upright on the ground or on a desk or shelf, and are typically used in network workstations or desktop computer applications. Rack-mount models can be mounted in standard 19-inch rack enclosures and can require anywhere from 1U to 12U (<a href="/wiki/Rack_unit" title="Rack unit">rack units</a>). They are typically used in server and networking applications. Some devices feature user interfaces that rotate 90°, allowing the devices to be mounted vertically on the ground or horizontally as would be found in a rack. </p> <div class="mw-heading mw-heading2"><h2 id="Applications">Applications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=12" title="Edit section: Applications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="N_+_1"><span id="N_.2B_1"></span><i>N</i> + 1</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=13" title="Edit section: N + 1"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In large business environments where reliability is of great importance, a single huge UPS can also be a single point of failure that can disrupt many other systems. To provide greater reliability, multiple smaller UPS modules and batteries can be integrated together to provide <a href="/wiki/Redundancy_(engineering)" title="Redundancy (engineering)">redundant</a> power protection equivalent to one very large UPS. "<i>N</i> + 1" means that if the load can be supplied by <i>N</i> modules, the installation will contain <i>N</i> + 1 modules. In this way, failure of one module will not impact system operation.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Multiple_redundancy">Multiple redundancy</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=14" title="Edit section: Multiple redundancy"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Many computer servers offer the option of redundant <a href="/wiki/Power_supply_unit_(computer)" title="Power supply unit (computer)">power supplies</a>, so that in the event of one power supply failing, one or more other power supplies are able to power the load. This is a critical point – each power supply must be able to power the entire server by itself. </p><p>Redundancy is further enhanced by plugging each power supply into a different circuit (i.e. to a different <a href="/wiki/Circuit_breaker" title="Circuit breaker">circuit breaker</a>). </p><p>Redundant protection can be extended further yet by connecting each power supply to its own UPS. This provides double protection from both a power supply failure and a UPS failure, so that continued operation is assured. This configuration is also referred to as 1 + 1 or 2<i>N</i> redundancy. If the budget does not allow for two identical UPS units then it is common practice to plug one power supply into <a href="/wiki/Mains_power" class="mw-redirect" title="Mains power">mains power</a> and the other into the UPS.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Outdoor_use">Outdoor use</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=15" title="Edit section: Outdoor use"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>When a UPS system is placed outdoors, it should have some specific features that guarantee that it can tolerate weather without any effects on performance. Factors such as temperature, <a href="/wiki/Humidity" title="Humidity">humidity</a>, rain, and snow among others should be considered by the manufacturer when designing an outdoor UPS system. <a href="/wiki/Operating_temperature" title="Operating temperature">Operating temperature</a> ranges for outdoor UPS systems could be around −40 °C to +55 <a href="/wiki/Celsius" title="Celsius">°C</a>.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p><p>Outdoor UPS systems can either be pole, ground (pedestal), or host mounted. Outdoor environment could mean extreme cold, in which case the outdoor UPS system should include a battery heater mat, or extreme heat, in which case the outdoor UPS system should include a fan system or an air conditioning system. </p> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Sunny_Boy_3000.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Sunny_Boy_3000.jpg/300px-Sunny_Boy_3000.jpg" decoding="async" width="300" height="273" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Sunny_Boy_3000.jpg/450px-Sunny_Boy_3000.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Sunny_Boy_3000.jpg/600px-Sunny_Boy_3000.jpg 2x" data-file-width="1562" data-file-height="1422" /></a><figcaption>Internal view of a solar inverter. Note the many large capacitors (blue cylinders), used to store energy briefly and improve the output waveform.</figcaption></figure> <p>A <b>solar inverter</b>, or <b>PV inverter</b>, or <b>solar converter</b>, converts the variable <a href="/wiki/Direct_current" title="Direct current">direct current</a> (DC) output of a <a href="/wiki/Photovoltaic" class="mw-redirect" title="Photovoltaic">photovoltaic</a> (PV) <a href="/wiki/Solar_panel" title="Solar panel">solar panel</a> into a <a href="/wiki/Utility_frequency" title="Utility frequency">utility frequency</a> <a href="/wiki/Alternating_current" title="Alternating current">alternating current</a> (AC) that can be fed into a commercial electrical <a href="/wiki/Utility_grid" class="mw-redirect" title="Utility grid">grid</a> or used by a local, <a href="/wiki/Off-grid" class="mw-redirect" title="Off-grid">off-grid</a> electrical network. It is a critical <a href="/wiki/Balance_of_system" title="Balance of system">BOS</a>–component in a <a href="/wiki/Photovoltaic_system" title="Photovoltaic system">photovoltaic system</a>, allowing the use of ordinary AC-powered equipment. Solar inverters have special functions adapted for use with photovoltaic arrays, including <a href="/wiki/Maximum_power_point_tracking" title="Maximum power point tracking">maximum power point tracking</a> and anti-<a href="/wiki/Islanding" title="Islanding">islanding</a> protection. </p> <div class="mw-heading mw-heading2"><h2 id="Harmonic_distortion">Harmonic distortion</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=16" title="Edit section: Harmonic distortion"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c4/APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg/360px-APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg" decoding="async" width="360" height="216" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c4/APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg/540px-APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c4/APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg/720px-APC_Back-UPS_550_Uninterruptible_Power_Supply_Output_Waveform.jpg 2x" data-file-width="1600" data-file-height="960" /></a><figcaption>UPS output waveform (yellow) compared to normal 120 VAC 60 Hz power waveform (violet)</figcaption></figure><p>The output of some electronic UPSes can have a significant departure from an ideal sinusoidal waveform. This is especially true of inexpensive consumer-grade single-phase units designed for home and office use. These often utilize simple switching AC power supplies and the output resembles a square wave rich in harmonics. These harmonics can cause interference with other electronic devices including radio communication, and some devices (e.g. inductive loads such as AC motors) may perform with reduced efficiency or not at all. More sophisticated (and expensive) UPS units can produce nearly pure sinusoidal AC power. </p><div class="mw-heading mw-heading2"><h2 id="Power_factor">Power factor</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=17" title="Edit section: Power factor"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Power_factor" title="Power factor">Power factor</a></div> <p>A problem in the combination of a double-conversion UPS and a generator is the voltage distortion created by the UPS. The input of a double-conversion UPS is essentially a big rectifier. The current drawn by the UPS is non-sinusoidal. This can cause the voltage from the AC mains or a generator to also become non-sinusoidal. The voltage distortion then can cause problems in all electrical equipment connected to that power source, including the UPS itself. It will also cause more power to be lost in the wiring supplying power to the UPS due to the spikes in current flow. This level of "noise" is measured as a percentage of "<a href="/wiki/Total_harmonic_distortion" title="Total harmonic distortion">total harmonic distortion of the current</a>" (THD<sub><i>I</i></sub>). Classic UPS rectifiers have a THD<sub><i>I</i></sub> level of around 25%–30%. To reduce voltage distortion, this requires heavier mains wiring or generators more than twice as large as the UPS. </p><p>There are several solutions to reduce the THD<sub><i>I</i></sub> in a double-conversion UPS: </p><p>Classic solutions such as passive filters reduce THD<sub><i>I</i></sub> to 5%–10% at full load. They are reliable, but big and only work at full load, and present their own problems when used in tandem with generators. </p><p>An alternative solution is an active filter. Through the use of such a device, THD<sub><i>I</i></sub> can drop to 5% over the full power range. The newest technology in double-conversion UPS units is a rectifier that does not use classic rectifier components (thyristors and diodes) but uses high-frequency components instead. A double-conversion UPS with an <a href="/wiki/Insulated-gate_bipolar_transistor" title="Insulated-gate bipolar transistor">insulated-gate bipolar transistor</a> rectifier and inductor can have a THD<sub><i>I</i></sub> as small as 2%. This completely eliminates the need to oversize the generator (and transformers), without additional filters, investment cost, losses, or space. </p> <div class="mw-heading mw-heading2"><h2 id="Communication">Communication</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=18" title="Edit section: Communication"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Expand_section plainlinks metadata ambox mbox-small-left ambox-content" role="presentation"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><a href="/wiki/File:Wiki_letter_w_cropped.svg" class="mw-file-description"><img alt="[icon]" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/20px-Wiki_letter_w_cropped.svg.png" decoding="async" width="20" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/30px-Wiki_letter_w_cropped.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/40px-Wiki_letter_w_cropped.svg.png 2x" data-file-width="44" data-file-height="31" /></a></span></td><td class="mbox-text"><div class="mbox-text-span">This section <b>needs expansion</b>. You can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Uninterruptible_power_supply&action=edit&section=">adding to it</a>. <span class="date-container"><i>(<span class="date">December 2009</span>)</i></span></div></td></tr></tbody></table> <p><a href="/wiki/Power_management" title="Power management">Power management</a> (PM) requires: </p> <ol><li>The UPS to report its status to the computer it powers via a communications link such as a <a href="/wiki/RS-232" title="RS-232">serial port</a>, <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> and <a href="/wiki/Simple_Network_Management_Protocol" title="Simple Network Management Protocol">Simple Network Management Protocol</a>, GSM/<a href="/wiki/GPRS" class="mw-redirect" title="GPRS">GPRS</a> or <a href="/wiki/USB" title="USB">USB</a></li> <li>A subsystem in the <a href="/wiki/Operating_system" title="Operating system">OS</a> that processes the reports and generates notifications, PM events, or commands an ordered shut down.<sup id="cite_ref-tldp_aen187_17-0" class="reference"><a href="#cite_note-tldp_aen187-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> Some UPS manufacturers publish their communication protocols, but other manufacturers (such as <a href="/wiki/American_Power_Conversion" class="mw-redirect" title="American Power Conversion">APC</a>) use <a href="/wiki/Proprietary_protocol" title="Proprietary protocol">proprietary protocols</a>.</li></ol> <p>The basic computer-to-UPS control methods are intended for one-to-one signaling from a single source to a single target. For example, a single UPS may connect to a single computer to provide status information about the UPS, and allow the computer to control the UPS. Similarly, the USB protocol is also intended to connect a single computer to multiple peripheral devices. </p><p>In some situations, it is useful for a single large UPS to be able to communicate with several protected devices. For traditional serial or USB control, a <i>signal replication</i> device may be used, which for example allows one UPS to connect to five computers using serial or USB connections.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> However, the splitting is typically only one direction from UPS to the devices to provide status information. Return control signals may only be permitted from one of the protected systems to the UPS.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p><p>As Ethernet has increased in common use since the 1990s, control signals are now commonly sent between a single UPS and multiple computers using standard Ethernet data communication methods such as <a href="/wiki/TCP/IP" class="mw-redirect" title="TCP/IP">TCP/IP</a>.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> The status and control information is typically encrypted so that, for example, an outside hacker can not gain control of the UPS and command it to shut down.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p><p>Distribution of UPS status and control data requires that all intermediary devices such as Ethernet switches or serial multiplexers be powered by one or more UPS systems, in order for the UPS alerts to reach the target systems during a <a href="/wiki/Power_outage" title="Power outage">power outage</a>. To avoid the dependency on Ethernet infrastructure, the UPSs can be connected directly to the main control server by using a GSM/GPRS channel also. The SMS or GPRS data packets sent from UPSs trigger software to shut down the PCs to reduce the load. </p> <div class="mw-heading mw-heading2"><h2 id="Batteries">Batteries</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=19" title="Edit section: Batteries"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:EPS_6000_Battery_Cabinet.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/EPS_6000_Battery_Cabinet.jpg/220px-EPS_6000_Battery_Cabinet.jpg" decoding="async" width="220" height="293" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/EPS_6000_Battery_Cabinet.jpg/330px-EPS_6000_Battery_Cabinet.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5f/EPS_6000_Battery_Cabinet.jpg/440px-EPS_6000_Battery_Cabinet.jpg 2x" data-file-width="2592" data-file-height="3456" /></a><figcaption>Battery cabinet</figcaption></figure> <p>There are three main types of UPS batteries: Valve Regulated Lead Acid (VRLA), Flooded Cell or VLA batteries, and lithium-ion batteries. The run-time for a battery-operated UPS depends on the type and size of batteries and rate of discharge, and the efficiency of the inverter. The total capacity of a <a href="/wiki/Lead%E2%80%93acid_battery" title="Lead–acid battery">lead–acid battery</a> is a function of the rate at which it is discharged, which is described as <a href="/wiki/Peukert%27s_law" title="Peukert's law">Peukert's law</a>. </p><p>Manufacturers supply run-time rating in minutes for packaged UPS systems. Larger systems (such as for data centers) require detailed calculation of the load, inverter efficiency, and battery characteristics to ensure the required endurance is attained.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Common_battery_characteristics_and_load_testing">Common battery characteristics and load testing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=20" title="Edit section: Common battery characteristics and load testing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>When a lead–acid battery is charged or discharged, this initially affects only the reacting chemicals, which are at the interface between the electrodes and the electrolyte. With time, the charge stored in the chemicals at the interface, often called "interface charge", spreads by <a href="/wiki/Diffusion" title="Diffusion">diffusion</a> of these chemicals throughout the volume of the active material. </p><p>If a battery has been completely discharged (e.g. the car lights were left on overnight) and next is given a fast charge for only a few minutes, then during the short charging time it develops only a charge near the interface. The battery voltage may rise to be close to the charger voltage so that the charging current decreases significantly. After a few hours, this interface charge will not spread to the volume of the electrode and electrolyte, leading to an interface charge so low that it may be insufficient to start a car.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> </p><p>Due to the interface charge, brief UPS <i>self-test</i> functions lasting only a few seconds may not accurately reflect the true runtime capacity of a UPS, and instead an extended <i>recalibration</i> or <i>rundown</i> test that deeply discharges the battery is needed.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> </p><p>The deep discharge testing is itself damaging to batteries due to the chemicals in the discharged battery starting to <a href="/wiki/Crystallize" class="mw-redirect" title="Crystallize">crystallize</a> into highly stable molecular shapes that will not re-dissolve when the battery is recharged, permanently reducing charge capacity. In lead-acid batteries, this is known as <a href="/wiki/Lead-acid_battery#Sulfation_and_desulfation" class="mw-redirect" title="Lead-acid battery">sulfation</a>, but deep-discharge damage also affects other types such as <a href="/wiki/Nickel-cadmium_batteries" class="mw-redirect" title="Nickel-cadmium batteries">nickel-cadmium batteries</a> and <a href="/wiki/Lithium_batteries" class="mw-redirect" title="Lithium batteries">lithium batteries</a>.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> Therefore, it is commonly recommended that rundown tests be performed infrequently, such as every six months to a year.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Testing_of_strings_of_batteries/cells"><span id="Testing_of_strings_of_batteries.2Fcells"></span>Testing of strings of batteries/cells</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=21" title="Edit section: Testing of strings of batteries/cells"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Multi-<a href="/wiki/Kilowatt" class="mw-redirect" title="Kilowatt">kilowatt</a> commercial UPS systems with large and easily accessible battery banks are capable of isolating and testing individual cells within a <i>battery string</i>, which consists of either combined-cell battery units (such as 12 V lead acid batteries) or individual chemical cells wired in series. Isolating a single cell and installing a jumper in place of it allows the one battery to be discharge-tested, while the rest of the battery string remains charged and available to provide protection.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p><p>It is also possible to measure the electrical characteristics of individual cells in a battery string, using intermediate sensor wires that are installed at every cell-to-cell junction, and monitored both individually and collectively. Battery strings may also be wired as series-parallel, for example, two sets of 20 cells. In such a situation it is also necessary to monitor current flow between parallel strings, as current may circulate between the strings to balance out the effects of weak cells, dead cells with high resistance, or shorted cells. For example, stronger strings can discharge through weaker strings until voltage imbalances are equalized, and this must be factored into the individual inter-cell measurements within each string.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Series-parallel_battery_interactions">Series-parallel battery interactions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=22" title="Edit section: Series-parallel battery interactions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Battery strings wired in <a href="/wiki/Series_and_parallel_circuits" title="Series and parallel circuits">series-parallel</a> can develop unusual failure modes due to interactions between the multiple parallel strings. Defective batteries in one string can adversely affect the operation and lifespan of good or new batteries in other strings. These issues also apply to other situations where series-parallel strings are used, not just in UPS systems but also in <a href="/wiki/Electric_vehicle" title="Electric vehicle">electric vehicle</a> applications.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p><p>Consider a series-parallel battery arrangement with all good cells, and one becomes shorted or dead: </p> <ul><li>The failed cell will reduce the maximum developed voltage for the entire series string it is within.</li> <li>Other series strings wired in parallel with the degraded string will now discharge through the degraded string until their voltage matches the voltage of the degraded string, potentially <a href="/wiki/Overcharging_(battery)" class="mw-redirect" title="Overcharging (battery)">overcharging</a> and leading to <a href="/wiki/Electrolyte" title="Electrolyte">electrolyte</a> boiling and outgassing from the remaining good cells in the degraded string. These parallel strings can now never be fully recharged, as the increased voltage will bleed off through the string containing the failed battery.</li> <li>Charging systems may attempt to gauge battery string capacity by measuring overall voltage. Due to the overall string voltage depletion due to the dead cells, the charging system may detect this as a state of discharge, and will continuously attempt to charge the series-parallel strings, which leads to continuous overcharging and damage to all the cells in the degraded series string containing the damaged battery.</li> <li>If <a href="/wiki/Lead%E2%80%93acid_battery" title="Lead–acid battery">lead-acid batteries</a> are used, all cells in the formerly good parallel strings will begin to sulfate due to the inability for them to be fully recharged, resulting in the storage capacity of these cells being permanently damaged, even if the damaged cell in the one degraded string is eventually discovered and replaced with a new one.</li></ul> <p>The only way to prevent these subtle series-parallel string interactions is by not using parallel strings at all and using separate charge controllers and inverters for individual series strings. </p> <div class="mw-heading mw-heading3"><h3 id="Series_new/old_battery_interactions"><span id="Series_new.2Fold_battery_interactions"></span>Series new/old battery interactions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=23" title="Edit section: Series new/old battery interactions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Even just a single string of batteries wired in series can have adverse interactions if new batteries are mixed with old batteries. Older batteries tend to have reduced storage capacity, and so will both discharge faster than new batteries and also charge to their maximum capacity more rapidly than new batteries. </p><p>As a mixed string of new and old batteries is depleted, the string voltage will drop, and when the old batteries are exhausted the new batteries still have charge available. The newer cells may continue to discharge through the rest of the string, but due to the low voltage this energy flow may not be useful and may be wasted in the old cells as resistance heating. </p><p>For cells that are supposed to operate within a specific discharge window, new cells with more capacity may cause the old cells in the series string to continue to discharge beyond the safe bottom limit of the discharge window, damaging the old cells. </p><p>When recharged, the old cells recharge more rapidly, leading to a rapid rise of voltage to near the fully charged state, but before the new cells with more capacity have fully recharged. The charge controller detects the high voltage of a nearly fully charged string and reduces current flow. The new cells with more capacity now charge very slowly, so slowly that the chemicals may begin to crystallize before reaching the fully charged state, reducing new cell capacity over several charge/discharge cycles until their capacity more closely matches the old cells in the series string. </p><p>For such reasons, some industrial UPS management systems recommend periodic replacement of entire battery arrays potentially using hundreds of expensive batteries, due to these damaging interactions between new batteries and old batteries, within and across series and parallel strings.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Standards">Standards</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=24" title="Edit section: Standards"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>IEC 62040-1:2017 Uninterruptible power systems (UPS) – Part 1: General and safety requirements for UPS</li> <li>IEC 62040-2:2016 Uninterruptible power systems (UPS) – Part 2: Electromagnetic compatibility (EMC) requirements</li> <li>IEC 62040-3:2021 Uninterruptible power systems (UPS) – Part 3: Method of specifying the performance and test requirements</li> <li>IEC 62040-4:2013 Uninterruptible power systems (UPS) – Part 4: Environmental aspects – Requirements and reporting</li></ul> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=25" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Battery_room" title="Battery room">Battery room</a></li> <li><a href="/wiki/Emergency_power_system" title="Emergency power system">Emergency power system</a></li> <li><a href="/wiki/Fuel_cell_applications" class="mw-redirect" title="Fuel cell applications">Fuel cell applications</a></li> <li><a href="/wiki/IT_baseline_protection" title="IT baseline protection">IT baseline protection</a></li> <li><a href="/wiki/Power_conditioner" title="Power conditioner">Power conditioner</a></li> <li><a href="/wiki/Dynamic_voltage_restoration" title="Dynamic voltage restoration">Dynamic voltage restoration</a></li> <li><a href="/wiki/Net_metering" title="Net metering">Net metering system with energy storage</a></li> <li><a href="/wiki/Surge_protector" title="Surge protector">Surge protector</a></li> <li><a href="/wiki/Switched-mode_power_supply" title="Switched-mode power supply">Switched-mode power supply</a> (SMPS)</li> <li><a href="/wiki/Switched-mode_power_supply_applications" class="mw-redirect" title="Switched-mode power supply applications">Switched-mode power supply applications</a></li> <li><a href="/wiki/Emergency_light" title="Emergency light">Emergency light</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=26" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">E-book on choosing a UPS topology based on application type <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20130326072420/http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Documents/White%20Papers/UPS%20Trap%20Doors%20for%20SMB.PDF">"Avoiding Trap Doors Associated with Purchasing a UPS System"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Documents/White%20Papers/UPS%20Trap%20Doors%20for%20SMB.PDF">the original</a> <span class="cs1-format">(PDF)</span> on 2013-03-26<span class="reference-accessdate">. Retrieved <span class="nowrap">2018-12-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Avoiding+Trap+Doors+Associated+with+Purchasing+a+UPS+System&rft_id=http%3A%2F%2Fwww.emersonnetworkpower.com%2Fen-US%2FBrands%2FLiebert%2FDocuments%2FWhite%2520Papers%2FUPS%2520Trap%2520Doors%2520for%2520SMB.PDF&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSolter2002" class="citation cs2">Solter, W. (2002), "A new international UPS classification by IEC 62040-3", <i>24th Annual International Telecommunications Energy Conference</i>, pp. <span class="nowrap">541–</span>545, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FINTLEC.2002.1048709">10.1109/INTLEC.2002.1048709</a>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7803-7512-2" title="Special:BookSources/0-7803-7512-2"><bdi>0-7803-7512-2</bdi></a>, <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:195862090">195862090</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=A+new+international+UPS+classification+by+IEC+62040-3&rft.btitle=24th+Annual+International+Telecommunications+Energy+Conference&rft.pages=%3Cspan+class%3D%22nowrap%22%3E541-%3C%2Fspan%3E545&rft.date=2002&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A195862090%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1109%2FINTLEC.2002.1048709&rft.isbn=0-7803-7512-2&rft.aulast=Solter&rft.aufirst=W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text">Detailed explanation of UPS topologies <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20130326072442/http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Documents/White%20Papers/High-Availability%20Power%20Systems,%20Part%20I_UPS%20Internal%20Topology.pdf">"High-Availability Power Systems, Part I: UPS Internal Topology"</a> <span class="cs1-format">(PDF)</span>. November 2000. Archived from <a rel="nofollow" class="external text" href="http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Documents/White%20Papers/High-Availability%20Power%20Systems,%20Part%20I_UPS%20Internal%20Topology.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2013-03-26<span class="reference-accessdate">. Retrieved <span class="nowrap">2018-12-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=High-Availability+Power+Systems%2C+Part+I%3A+UPS+Internal+Topology&rft.date=2000-11&rft_id=http%3A%2F%2Fwww.emersonnetworkpower.com%2Fen-US%2FBrands%2FLiebert%2FDocuments%2FWhite%2520Papers%2FHigh-Availability%2520Power%2520Systems%2C%2520Part%2520I_UPS%2520Internal%2520Topology.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">Uninterruptible power supply FAQ <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.eaton.com/us/en-us/products/backup-power-ups-surge-it-power-distribution/backup-power-ups/uninterruptible-power-supply-faq.html">"Uninterruptible power supply FAQ"</a>. May 2019<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-30</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Uninterruptible+power+supply+FAQ&rft.date=2019-05&rft_id=https%3A%2F%2Fwww.eaton.com%2Fus%2Fen-us%2Fproducts%2Fbackup-power-ups-surge-it-power-distribution%2Fbackup-power-ups%2Funinterruptible-power-supply-faq.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20131004222451/http://www.stacoenergy.com/ups/on-line-uninterruptible-power-supply.htm">"UPS On-Line Uninterruptible Power Supply Backup Power Source"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.stacoenergy.com/ups/on-line-uninterruptible-power-supply.htm">the original</a> on October 4, 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=UPS+On-Line+Uninterruptible+Power+Supply+Backup+Power+Source&rft_id=http%3A%2F%2Fwww.stacoenergy.com%2Fups%2Fon-line-uninterruptible-power-supply.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20210114004421/https://powercontrol.co.uk/blog/choosing-ups-system-for-business/">"Choosing the Right UPS System for Your Business - Power Control Ltd - Uninterruptible Power Supply Solutions, UPS Maintenance & UPS Installation"</a>. Archived from <a rel="nofollow" class="external text" href="https://powercontrol.co.uk/blog/choosing-ups-system-for-business/">the original</a> on 2021-01-14<span class="reference-accessdate">. Retrieved <span class="nowrap">2021-01-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Choosing+the+Right+UPS+System+for+Your+Business+-+Power+Control+Ltd+-+Uninterruptible+Power+Supply+Solutions%2C+UPS+Maintenance+%26+UPS+Installation&rft_id=https%3A%2F%2Fpowercontrol.co.uk%2Fblog%2Fchoosing-ups-system-for-business%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-Rotary_UPS-7"><span class="mw-cite-backlink">^ <a href="#cite_ref-Rotary_UPS_7-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Rotary_UPS_7-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20141204152131/http://www.pscpower.com/site/wp-content/uploads/2013/06/Hybrid-Rotary-UPS.pdf">"Hybrid Rotary UPS"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.pscpower.com/site/wp-content/uploads/2013/06/Hybrid-Rotary-UPS.pdf">the original</a> <span class="cs1-format">(PDF)</span> on December 4, 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Hybrid+Rotary+UPS&rft_id=http%3A%2F%2Fwww.pscpower.com%2Fsite%2Fwp-content%2Fuploads%2F2013%2F06%2FHybrid-Rotary-UPS.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-HPman-8"><span class="mw-cite-backlink">^ <a href="#cite_ref-HPman_8-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-HPman_8-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01173322/c01173322.pdf">"Increasing energy efficiency with modular HP three-phase power distribution"</a> <span class="cs1-format">(PDF)</span>. <a href="/wiki/HP_Inc." title="HP Inc.">HP</a>. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01173322/c01173322.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Increasing+energy+efficiency+with+modular+HP+three-phase+power+distribution&rft.pub=HP&rft_id=http%3A%2F%2Fh20000.www2.hp.com%2Fbc%2Fdocs%2Fsupport%2FSupportManual%2Fc01173322%2Fc01173322.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTonFortenberyTschudi2007" class="citation web cs1">Ton, My; Fortenbery, Brian; Tschudi, William (January 2007). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101008075806/http://hightech.lbl.gov/documents/DATA_CENTERS/DCDemoFinalReport.pdf">"DC Power for Improved Data Center Efficiency"</a> <span class="cs1-format">(PDF)</span>. Lawrence Berkeley National Laboratory. Archived from <a rel="nofollow" class="external text" href="http://hightech.lbl.gov/documents/DATA_CENTERS/DCDemoFinalReport.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2010-10-08.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=DC+Power+for+Improved+Data+Center+Efficiency&rft.pub=Lawrence+Berkeley+National+Laboratory&rft.date=2007-01&rft.aulast=Ton&rft.aufirst=My&rft.au=Fortenbery%2C+Brian&rft.au=Tschudi%2C+William&rft_id=http%3A%2F%2Fhightech.lbl.gov%2Fdocuments%2FDATA_CENTERS%2FDCDemoFinalReport.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://powertechniquesinc.com/wp-content/uploads/2015/08/Active-Power-WP-107-15-Seconds-vs-15-Minutes.pdf">"15 Seconds versus 15 Minutes: White Paper 107 Designing for High Availability"</a> <span class="cs1-format">(PDF)</span>. Active Power. 2007. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/http://powertechniquesinc.com/wp-content/uploads/2015/08/Active-Power-WP-107-15-Seconds-vs-15-Minutes.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=15+Seconds+versus+15+Minutes%3A+White+Paper+107+Designing+for+High+Availability&rft.pub=Active+Power&rft.date=2007&rft_id=http%3A%2F%2Fpowertechniquesinc.com%2Fwp-content%2Fuploads%2F2015%2F08%2FActive-Power-WP-107-15-Seconds-vs-15-Minutes.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDorf2018" class="citation book cs1">Dorf, Richard C. (2018-12-14). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=n2C1DwAAQBAJ&dq=rotary+ups&pg=SA9-PA81"><i>The Electrical Engineering Handbook - Six Volume Set</i></a>. CRC Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-4200-4975-6" title="Special:BookSources/978-1-4200-4975-6"><bdi>978-1-4200-4975-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Electrical+Engineering+Handbook+-+Six+Volume+Set&rft.pub=CRC+Press&rft.date=2018-12-14&rft.isbn=978-1-4200-4975-6&rft.aulast=Dorf&rft.aufirst=Richard+C.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dn2C1DwAAQBAJ%26dq%3Drotary%2Bups%26pg%3DSA9-PA81&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.tripplite.com/products/ups-Buying-Guide">"UPS Buying Guide"</a>. <i>TrippLite.com</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=TrippLite.com&rft.atitle=UPS+Buying+Guide&rft_id=https%3A%2F%2Fwww.tripplite.com%2Fproducts%2Fups-Buying-Guide&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text">Detailed explanation of optimized <i>N</i> + 1 configurations<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160303221250/http://www.emersonnetworkpower-partner.com/ArticleDocuments/172/Balancing%20Scalability%20and%20Reliability%20in%20the%20Critical%20Power%20System.pdf.aspx">"Balancing Scalability and Reliability in the Critical Power System: When Does <i>N</i> + 1 Become Too Many + 1?"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.emersonnetworkpower-partner.com/ArticleDocuments/172/Balancing%20Scalability%20and%20Reliability%20in%20the%20Critical%20Power%20System.pdf.aspx">the original</a> <span class="cs1-format">(PDF)</span> on 2016-03-03.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Balancing+Scalability+and+Reliability+in+the+Critical+Power+System%3A+When+Does+N+%2B+1+Become+Too+Many+%2B+1%3F&rft_id=http%3A%2F%2Fwww.emersonnetworkpower-partner.com%2FArticleDocuments%2F172%2FBalancing%2520Scalability%2520and%2520Reliability%2520in%2520the%2520Critical%2520Power%2520System.pdf.aspx&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text">Detailed explanation of UPS redundancy options<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20130326072431/http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Documents/White%20Papers/High-Availability%20Power%20Systems,%20Part%20II_Redundancy%20Options.pdf">"High-Availability Power Systems, Part II: Redundancy Options"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Documents/White%20Papers/High-Availability%20Power%20Systems,%20Part%20II_Redundancy%20Options.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2013-03-26<span class="reference-accessdate">. Retrieved <span class="nowrap">2018-12-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=High-Availability+Power+Systems%2C+Part+II%3A+Redundancy+Options&rft_id=http%3A%2F%2Fwww.emersonnetworkpower.com%2Fen-US%2FBrands%2FLiebert%2FDocuments%2FWhite%2520Papers%2FHigh-Availability%2520Power%2520Systems%2C%2520Part%2520II_Redundancy%2520Options.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHeydari-doostabad2019" class="citation journal cs1">Heydari-doostabad, Hamed (January 2019). <a rel="nofollow" class="external text" href="https://www.sciencedirect.com/science/article/pii/S0142061517316083">"A new approach to design an observer for load current of UPS based on Fourier series theory in model predictive control system"</a>. <i>International Journal of Electrical Power & Energy Systems</i>. <b>104</b> (1): <span class="nowrap">898–</span>909. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2019IJEPE.104..898H">2019IJEPE.104..898H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.ijepes.2018.07.047">10.1016/j.ijepes.2018.07.047</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0142-0615">0142-0615</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:116458248">116458248</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=International+Journal+of+Electrical+Power+%26+Energy+Systems&rft.atitle=A+new+approach+to+design+an+observer+for+load+current+of+UPS+based+on+Fourier+series+theory+in+model+predictive+control+system&rft.volume=104&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E898-%3C%2Fspan%3E909&rft.date=2019-01&rft_id=info%3Adoi%2F10.1016%2Fj.ijepes.2018.07.047&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A116458248%23id-name%3DS2CID&rft.issn=0142-0615&rft_id=info%3Abibcode%2F2019IJEPE.104..898H&rft.aulast=Heydari-doostabad&rft.aufirst=Hamed&rft_id=https%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0142061517316083&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text">Refer to safety standard IEC 60950-22 or a local derivative according to location e.g. EN 60950-22 (Europe); UL 60950-22 (USA)</span> </li> <li id="cite_note-tldp_aen187-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-tldp_aen187_17-0">^</a></b></span> <span class="reference-text">Raymond, Eric Steven. <a rel="nofollow" class="external text" href="http://tldp.org/HOWTO/UPS-HOWTO/x142.html#AEN187">UPS HOWTO, section 3.3</a>. The Linux Documentation Project, 2003–2007.</span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGenerex" class="citation web cs1">Generex. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120127190246/http://www.generex.de/generex/download/manuals/manual_MULTIXS_en.pdf">"Multi-XS User Manual"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.generex.de/generex/download/manuals/manual_MULTIXS_en.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2012-01-27<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-11-14</span></span>. <q>Multi-XS is an active RS232 data switch, designed to handle serial communications of one UPS with up to 5 / 10 computers</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Multi-XS+User+Manual&rft.au=Generex&rft_id=http%3A%2F%2Fwww.generex.de%2Fgenerex%2Fdownload%2Fmanuals%2Fmanual_MULTIXS_en.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text">APC AP9207 Share-UPS, User Manual, pp. 6–7, <i>Port 1 is called the Advanced port because it supplies smart signaling, which provides the advanced capabilities available to a server running PowerChute plus software. The Advanced port provides full access to the Computer Interface port of the UPS.</i> <i> Ports 2–8 on the rear panel of Share-UPS are called Basic ports because they supply simple UPS signaling for On Battery and Low Battery conditions in the UPS.</i> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20120424231213/http://www.apcmedia.com/salestools/ASTE-6Z5QCB_R0_EN.pdf">"Share-UPS User Manual"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.apcmedia.com/salestools/ASTE-6Z5QCB_R0_EN.pdf">the original</a> <span class="cs1-format">(PDF)</span> on April 24, 2012<span class="reference-accessdate">. Retrieved <span class="nowrap">November 14,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Share-UPS+User+Manual&rft_id=http%3A%2F%2Fwww.apcmedia.com%2Fsalestools%2FASTE-6Z5QCB_R0_EN.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">An example of an Ethernet UPS controller: <a rel="nofollow" class="external text" href="http://emersonnetworkpower.com/EN-US/PRODUCTS/MONITORING/FORLARGEDATACENTER/ADVANCEDMONITORING/Pages/LiebertIntelliSlotWebCardCommunicationsInterfaceCard.aspx">Liebert IntelliSlot Web Card Communications Interface Card</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160413232114/http://emersonnetworkpower.com/EN-US/PRODUCTS/MONITORING/FORLARGEDATACENTER/ADVANCEDMONITORING/Pages/LiebertIntelliSlotWebCardCommunicationsInterfaceCard.aspx">Archived</a> 2016-04-13 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a></span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text">APC Application Note #67 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20120424231216/http://www.apcmedia.com/salestools/VAVR-5ZJSVU_R2_EN.pdf">"APC Network Management Card Security Implementation"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.apcmedia.com/salestools/VAVR-5ZJSVU_R2_EN.pdf">the original</a> <span class="cs1-format">(PDF)</span> on April 24, 2012<span class="reference-accessdate">. Retrieved <span class="nowrap">November 14,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=APC+Network+Management+Card+Security+Implementation&rft_id=http%3A%2F%2Fwww.apcmedia.com%2Fsalestools%2FVAVR-5ZJSVU_R2_EN.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.powerstream.com/battery-capacity-calculations.htm">"How to calculate battery run-time"</a>. PowerStream Technologies<span class="reference-accessdate">. Retrieved <span class="nowrap">2010-04-26</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=How+to+calculate+battery+run-time&rft.pub=PowerStream+Technologies&rft_id=http%3A%2F%2Fwww.powerstream.com%2Fbattery-capacity-calculations.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSaslow2002" class="citation book cs1">Saslow, Wayne M. (2002). <i>Electricity, Magnetism, and Light</i>. Toronto: Thomson Learning. pp. <span class="nowrap">302–</span>4. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-12-619455-6" title="Special:BookSources/0-12-619455-6"><bdi>0-12-619455-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Electricity%2C+Magnetism%2C+and+Light&rft.place=Toronto&rft.pages=%3Cspan+class%3D%22nowrap%22%3E302-%3C%2Fspan%3E4&rft.pub=Thomson+Learning&rft.date=2002&rft.isbn=0-12-619455-6&rft.aulast=Saslow&rft.aufirst=Wayne+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeter_M._Curtis2011" class="citation book cs1">Peter M. Curtis (2011). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=GVczgy4BkU8C&q=ups+battery+rundown&pg=PA261"><i>Maintaining Mission Critical Systems in a 24/7 Environment</i></a>. Wiley. pp. <span class="nowrap">261–</span>262. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781118041628" title="Special:BookSources/9781118041628"><bdi>9781118041628</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Maintaining+Mission+Critical+Systems+in+a+24%2F7+Environment&rft.pages=%3Cspan+class%3D%22nowrap%22%3E261-%3C%2Fspan%3E262&rft.pub=Wiley&rft.date=2011&rft.isbn=9781118041628&rft.au=Peter+M.+Curtis&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DGVczgy4BkU8C%26q%3Dups%2Bbattery%2Brundown%26pg%3DPA261&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichael_F._Hordeski2005" class="citation book cs1">Michael F. Hordeski (2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=jXIwvQTzX6UC&q=deep+discharge+crystallize&pg=PA70"><i>Emergency and backup power sources: preparing for blackouts and brownouts</i></a>. The Fairmont Press, Inc. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780881734850" title="Special:BookSources/9780881734850"><bdi>9780881734850</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Emergency+and+backup+power+sources%3A+preparing+for+blackouts+and+brownouts&rft.pub=The+Fairmont+Press%2C+Inc.&rft.date=2005&rft.isbn=9780881734850&rft.au=Michael+F.+Hordeski&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DjXIwvQTzX6UC%26q%3Ddeep%2Bdischarge%2Bcrystallize%26pg%3DPA70&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLeonardo_Energy" class="citation web cs1">Leonardo Energy. <a rel="nofollow" class="external text" href="http://d5.leonardo-energy.org/webfm_send/4011">"Maintenance Manager's Guide, Section 2.1"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">August 1,</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Maintenance+Manager%27s+Guide%2C+Section+2.1&rft.au=Leonardo+Energy&rft_id=http%3A%2F%2Fd5.leonardo-energy.org%2Fwebfm_send%2F4011&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span><sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link tagged June 2016">dead link</span></a></i><span style="visibility:hidden; color:transparent; padding-left:2px">‍</span>]</span></sup></span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAPC_Inc" class="citation web cs1">APC Inc. <a rel="nofollow" class="external text" href="http://nam-en.apc.com/app/answers/detail/a_id/8301/kw/runtime+calibration/session/L3RpbWUvMTMyMTMxMzA4My9zaWQvM0pOZkE3Sms%3D">"Knowledgebase article: What is the expected life of my APC UPS battery?, Answer ID 8301"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Knowledgebase+article%3A+What+is+the+expected+life+of+my+APC+UPS+battery%3F%2C+Answer+ID+8301&rft.au=APC+Inc&rft_id=http%3A%2F%2Fnam-en.apc.com%2Fapp%2Fanswers%2Fdetail%2Fa_id%2F8301%2Fkw%2Fruntime%2Bcalibration%2Fsession%2FL3RpbWUvMTMyMTMxMzA4My9zaWQvM0pOZkE3Sms%253D&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span><sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link tagged May 2014">dead link</span></a></i><span style="visibility:hidden; color:transparent; padding-left:2px">‍</span>]</span></sup></span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.datacenterjournal.com/facilities-news/306-electricalElectrical/2639-maintaining-and-testing-your-ups-system-to-ensure-continuous-power">"Maintaining and Testing Your UPS System to Ensure Continuous Power, Section: Maintaining a Battery Bank"</a>. <i>The Data Center Journal</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Data+Center+Journal&rft.atitle=Maintaining+and+Testing+Your+UPS+System+to+Ensure+Continuous+Power%2C+Section%3A+Maintaining+a+Battery+Bank&rft_id=http%3A%2F%2Fwww.datacenterjournal.com%2Ffacilities-news%2F306-electricalElectrical%2F2639-maintaining-and-testing-your-ups-system-to-ensure-continuous-power&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span> <sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link tagged July 2016">permanent dead link</span></a></i><span style="visibility:hidden; color:transparent; padding-left:2px">‍</span>]</span></sup> </span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20120401023942/http://www.btechinc.com/btech-focus-battery%20failure.shtml">BTECH Inc, BTECH's Focus – Predicting Battery Failure</a> and <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140622185615/http://www.btechinc.com/docs/S5/S5%20Installation%20Manual.pdf">Installation Manual</a>, page 18, showing sensor wires for each cell/battery on a battery string, and also note that the current transducer sensors to detect cross-string series-parallel current recirculation.</span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation encyclopaedia cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20200609233517/https://www.mpoweruk.com/balancing.htm">"Cell Balancing"</a>. <i>Electropaedia</i>. Woodbank Communications. Archived from <a rel="nofollow" class="external text" href="https://www.mpoweruk.com/balancing.htm">the original</a> on 2020-06-09<span class="reference-accessdate">. Retrieved <span class="nowrap">2020-05-28</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Cell+Balancing&rft.btitle=Electropaedia&rft.pub=Woodbank+Communications&rft_id=https%3A%2F%2Fwww.mpoweruk.com%2Fbalancing.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCotton2005" class="citation magazine cs1">Cotton, Bart (January 2005). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20130406210343/https://datapowermonitoring.com/pdfs/battery_asset_mgmt.pdf">"Battery Asset Management: VRLA ageing characteristics"</a> <span class="cs1-format">(PDF)</span>. <i>Batteries International</i>. Archived from <a rel="nofollow" class="external text" href="https://datapowermonitoring.com/pdfs/battery_asset_mgmt.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2013-04-06.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Batteries+International&rft.atitle=Battery+Asset+Management%3A+VRLA+ageing+characteristics&rft.date=2005-01&rft.aulast=Cotton&rft.aufirst=Bart&rft_id=https%3A%2F%2Fdatapowermonitoring.com%2Fpdfs%2Fbattery_asset_mgmt.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Uninterruptible_power_supply&action=edit&section=27" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Commons-logo.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/45px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/59px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></a></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Uninterruptible_power_supply" class="extiw" title="commons:Category:Uninterruptible power supply">Uninterruptible power supply</a></span>.</div></div> </div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2">Scott Siddens (February 2007), <a rel="nofollow" class="external text" href="https://web.archive.org/web/20091109032733/http://www.plantengineering.com/article/186039-UPS_on_the_front_line.php"><i>UPS on the front line</i></a>, Plant Engineering, archived from <a rel="nofollow" class="external text" href="http://www.plantengineering.com/article/186039-UPS_on_the_front_line.php">the original</a> on 2009-11-09</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=UPS+on+the+front+line&rft.pub=Plant+Engineering&rft.date=2007-02&rft.au=Scott+Siddens&rft_id=http%3A%2F%2Fwww.plantengineering.com%2Farticle%2F186039-UPS_on_the_front_line.php&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2">Cottuli, Carol (2011), <a rel="nofollow" class="external text" href="http://www.apcmedia.com/salestools/DBOY-78KRZE/DBOY-78KRZE_R2_EN.pdf"><i>Comparison of Static and Rotary UPS</i></a> <span class="cs1-format">(PDF)</span>, Schneider Electric, White Paper 92 rev. 2, <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/http://www.apcmedia.com/salestools/DBOY-78KRZE/DBOY-78KRZE_R2_EN.pdf">archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09<span class="reference-accessdate">, retrieved <span class="nowrap">April 7,</span> 2012</span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Comparison+of+Static+and+Rotary+UPS&rft.pub=Schneider+Electric&rft.date=2011&rft.aulast=Cottuli&rft.aufirst=Carol&rft_id=http%3A%2F%2Fwww.apcmedia.com%2Fsalestools%2FDBOY-78KRZE%2FDBOY-78KRZE_R2_EN.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2">Rasmussen, Neil (2011), <a rel="nofollow" class="external text" href="http://www.apcmedia.com/salestools/SADE-5TNM3Y/SADE-5TNM3Y_R7_EN.pdf?sdirect=true"><i>The Different Types of UPS Systems</i></a> <span class="cs1-format">(PDF)</span>, Schneider Electric, White Paper 1 rev. 7<span class="reference-accessdate">, retrieved <span class="nowrap">April 7,</span> 2012</span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Different+Types+of+UPS+Systems&rft.pub=Schneider+Electric&rft.date=2011&rft.aulast=Rasmussen&rft.aufirst=Neil&rft_id=http%3A%2F%2Fwww.apcmedia.com%2Fsalestools%2FSADE-5TNM3Y%2FSADE-5TNM3Y_R7_EN.pdf%3Fsdirect%3Dtrue&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2">VanDee, Dawn (March 1, 1999), <a rel="nofollow" class="external text" href="https://web.archive.org/web/20201130173502/http://ecmweb.com/mag/electric_rounding_rotary_ups/">"Rounding Up Rotary UPS Features"</a>, <i>EC&M</i>, Penton Business Media, archived from <a rel="nofollow" class="external text" href="http://ecmweb.com/mag/electric_rounding_rotary_ups/">the original</a> on November 30, 2020<span class="reference-accessdate">, retrieved <span class="nowrap">April 7,</span> 2012</span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=EC%26M&rft.atitle=Rounding+Up+Rotary+UPS+Features&rft.date=1999-03-01&rft.aulast=VanDee&rft.aufirst=Dawn&rft_id=http%3A%2F%2Fecmweb.com%2Fmag%2Felectric_rounding_rotary_ups%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLoefflerSpears2022" class="citation journal cs1">Loeffler, Chris; Spears, Ed (2022). <a rel="nofollow" class="external text" href="https://www.eaton.com/content/dam/eaton/products/backup-power-ups-surge-it-power-distribution/backup-power-ups/eaton-ferrups-tower-ups/Eaton-UPS-basics-whitepaper-WP1530005EN.pdf">"UPS basics"</a> <span class="cs1-format">(PDF)</span>. <i>White Paper – Markets Served – Data Centers</i>: 8. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20240229114953/https://www.eaton.com/content/dam/eaton/products/backup-power-ups-surge-it-power-distribution/backup-power-ups/eaton-ferrups-tower-ups/Eaton-UPS-basics-whitepaper-WP1530005EN.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2024-02-29<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-02-29</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=White+Paper+%26ndash%3B+Markets+Served+%26ndash%3B+Data+Centers&rft.atitle=UPS+basics&rft.pages=8&rft.date=2022&rft.aulast=Loeffler&rft.aufirst=Chris&rft.au=Spears%2C+Ed&rft_id=https%3A%2F%2Fwww.eaton.com%2Fcontent%2Fdam%2Featon%2Fproducts%2Fbackup-power-ups-surge-it-power-distribution%2Fbackup-power-ups%2Featon-ferrups-tower-ups%2FEaton-UPS-basics-whitepaper-WP1530005EN.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20150530053241/http://novaelectric.com/information/application-notes/the-different-type-of-ups-systems-available/"><i>The Different Type of UPS Systems Available</i></a>, archived from <a rel="nofollow" class="external text" href="http://novaelectric.com/information/application-notes/the-different-type-of-ups-systems-available">the original</a> on 2015-05-30</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Different+Type+of+UPS+Systems+Available&rft_id=http%3A%2F%2Fnovaelectric.com%2Finformation%2Fapplication-notes%2Fthe-different-type-of-ups-systems-available&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUninterruptible+power+supply" class="Z3988"></span></li></ul>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Uninterruptible_power_supply&oldid=1273691375">https://en.wikipedia.org/w/index.php?title=Uninterruptible_power_supply&oldid=1273691375</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Uninterruptible_power_supply" title="Category:Uninterruptible power supply">Uninterruptible power supply</a></li><li><a href="/wiki/Category:Electric_power_systems_components" title="Category:Electric power systems components">Electric power systems components</a></li><li><a href="/wiki/Category:Fault_tolerance" title="Category:Fault tolerance">Fault tolerance</a></li><li><a href="/wiki/Category:Voltage_stability" title="Category:Voltage stability">Voltage stability</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Webarchive_template_wayback_links" title="Category:Webarchive template wayback links">Webarchive template wayback links</a></li><li><a href="/wiki/Category:All_articles_with_dead_external_links" title="Category:All articles with dead external links">All articles with dead external links</a></li><li><a href="/wiki/Category:Articles_with_dead_external_links_from_June_2016" title="Category:Articles with dead external links from June 2016">Articles with dead external links from June 2016</a></li><li><a href="/wiki/Category:Articles_with_dead_external_links_from_May_2014" title="Category:Articles with dead external links from May 2014">Articles with dead external links from May 2014</a></li><li><a href="/wiki/Category:Articles_with_dead_external_links_from_July_2016" title="Category:Articles with dead external links from July 2016">Articles with dead external links from July 2016</a></li><li><a href="/wiki/Category:Articles_with_permanently_dead_external_links" title="Category:Articles with permanently dead external links">Articles with permanently dead external links</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Wikipedia_articles_needing_clarification_from_May_2012" title="Category:Wikipedia articles needing clarification from May 2012">Wikipedia articles needing clarification from May 2012</a></li><li><a href="/wiki/Category:Articles_to_be_expanded_from_December_2009" title="Category:Articles to be expanded from December 2009">Articles to be expanded from December 2009</a></li><li><a href="/wiki/Category:All_articles_to_be_expanded" title="Category:All articles to be expanded">All articles to be expanded</a></li><li><a href="/wiki/Category:Commons_category_link_from_Wikidata" title="Category:Commons category link from Wikidata">Commons category link from Wikidata</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 3 February 2025, at 15:12<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Uninterruptible_power_supply&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" lang="en" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/w/resources/assets/poweredby_mediawiki.svg" width="88" height="31"><img src="/w/resources/assets/mediawiki_compact.svg" alt="Powered by MediaWiki" width="25" height="25" loading="lazy"></picture></a></li> </ul> </footer> </div> </div> </div> <div class="vector-header-container vector-sticky-header-container"> <div id="vector-sticky-header" class="vector-sticky-header"> <div class="vector-sticky-header-start"> <div class="vector-sticky-header-icon-start vector-button-flush-left vector-button-flush-right" aria-hidden="true"> <button class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-sticky-header-search-toggle" tabindex="-1" data-event-name="ui.vector-sticky-search-form.icon"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </button> </div> <div role="search" class="vector-search-box-vue vector-search-box-show-thumbnail vector-search-box"> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail"> <form action="/w/index.php" id="vector-sticky-search-form" class="cdx-search-input cdx-search-input--has-end-button"> <div class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia"> <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <div class="vector-sticky-header-context-bar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-sticky-header-toc" class="vector-dropdown mw-portlet mw-portlet-sticky-header-toc vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" ><span class="mw-page-title-main">Uninterruptible power supply</span></div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history mw-ui-icon-wikimedia-wikimedia-history"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-star mw-ui-icon-wikimedia-wikimedia-star"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-wikiText mw-ui-icon-wikimedia-wikimedia-wikiText"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>48 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-6b845c894c-qmbwj","wgBackendResponseTime":137,"wgPageParseReport":{"limitreport":{"cputime":"0.586","walltime":"0.733","ppvisitednodes":{"value":2775,"limit":1000000},"postexpandincludesize":{"value":79653,"limit":2097152},"templateargumentsize":{"value":4035,"limit":2097152},"expansiondepth":{"value":17,"limit":100},"expensivefunctioncount":{"value":7,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":121227,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 641.187 1 -total"," 47.49% 304.494 1 Template:Reflist"," 26.34% 168.860 19 Template:Cite_web"," 13.37% 85.705 1 Template:Short_description"," 12.74% 81.704 1 Template:Commons_category"," 12.37% 79.344 1 Template:Sister_project"," 12.03% 77.136 1 Template:Side_box"," 9.34% 59.857 4 Template:Fix"," 7.64% 48.984 2 Template:Pagetype"," 6.25% 40.081 1 Template:Elucidate"]},"scribunto":{"limitreport-timeusage":{"value":"0.362","limit":"10.000"},"limitreport-memusage":{"value":6489654,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-84749c7844-s4hhc","timestamp":"20250210045110","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Uninterruptible power supply","url":"https:\/\/en.wikipedia.org\/wiki\/Uninterruptible_power_supply","sameAs":"http:\/\/www.wikidata.org\/entity\/Q207696","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q207696","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2002-02-26T00:38:54Z","dateModified":"2025-02-03T15:12:59Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/f\/f4\/UPSFrontView.jpg","headline":"electrical device that uses batteries to prevent a power flow interruption"}</script> </body> </html>