Protection circuit for 3 phase bridge misconnection? | Electronics Forum (Circuits, Projects and Microcontrollers)

<!DOCTYPE html> <html id="XF" lang="en-US" dir="LTR" data-app="public" data-template="thread_view_type_question" data-container-key="node-7" data-content-key="thread-166583" data-logged-in="false" data-cookie-prefix="xf_" data-csrf="1732730262,586d9f0d168bef66a70ad8169517e6b5" class="has-no-js template-thread_view_type_question XenBase layout-classic style-light sidebar-right xb-toggle-default xb-sidebar-show" > <head> <link rel="amphtml" href="https://www.electro-tech-online.com/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/?amp=1"> <meta charset="utf-8" /> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover"> <meta name="google-site-verification" content="8aECyKQ0jTEfZHF2mNguWwCvxcGSDIcHlRgLdE6BSCE" />  <script async src="https://securepubads.g.doubleclick.net/tag/js/gpt.js"></script> <script> window.googletag = window.googletag || {cmd: []}; googletag.cmd.push(function() { var pathParts = window.location.pathname.substr(1).split('/'); var mapHeader = googletag.sizeMapping() .addSize([768, 200], [728, 90]) .addSize([0, 0], [300, 250]) .build(); var mapLargeHeader = googletag.sizeMapping() .addSize([1024, 200], [[970, 90], [970, 250]]) .addSize([0, 0], [300, 250]) .build(); var mapWallpaper = googletag.sizeMapping() .addSize([1024, 500], [[1, 1]]) .addSize([0, 0], [[1, 1]]) .build(); var gptSlots = []; gptSlots[0] = googletag.defineSlot('/5272491/ee_network/eto_header', [[300, 250], [728, 90]], 'div-gpt-eto-header') .defineSizeMapping(mapHeader) .addService(googletag.pubads()); gptSlots[1] = googletag.defineSlot('/5272491/ee_network/eto_largeleader', [[970, 90], [970, 250]], 'div-gpt-eto_largeleader') .defineSizeMapping(mapLargeHeader) .addService(googletag.pubads()); gptSlots[2] = googletag.defineSlot('/5272491/ee_network/eto_wallpaper', [[1, 1]], 'div-gpt-eto_wallpaper') .defineSizeMapping(mapWallpaper) .addService(googletag.pubads()); googletag.defineSlot('/5272491/ee_network/eto_customsearchbox', [[300, 90]], 'div-gpt-eto_customsearchbox').addService(googletag.pubads()); googletag.defineSlot('/5272491/ee_network/eto_sidebar1', [[300, 250], [300, 600]], 'div-gpt-eto_sidebar1').addService(googletag.pubads()); googletag.defineSlot('/5272491/ee_network/eto_sidebarbottom', [[300, 250], [300, 600]], 'div-gpt-eto_sidebarbottom').addService(googletag.pubads()); googletag.defineSlot('/5272491/ee_network/eto_thread1', [[728, 90]], 'div-gpt-eto_thread1').addService(googletag.pubads()); googletag.defineSlot('/5272491/ee_network/eto_thread2', [[728, 90]], 'div-gpt-eto_thread2').addService(googletag.pubads()); googletag.defineSlot('/5272491/ee_network/eto_thread3', [[728, 90]], 'div-gpt-eto_thread3').addService(googletag.pubads()); googletag.pubads().enableSingleRequest(); googletag.pubads().collapseEmptyDivs(); googletag.pubads().setTargeting('articletitle', pathParts[0] ? pathParts[0]: 'home-page'); googletag.enableServices(); }); </script>  <title>Protection circuit for 3 phase bridge misconnection? | Electronics Forum (Circuits, Projects and Microcontrollers)</title> <link rel="manifest" href="/webmanifest.php"> <meta name="theme-color" content="#232a35" /> <meta name="apple-mobile-web-app-title" content="Electronics Forum (Circuits, Projects and Microcontrollers)"> <meta name="description" content="Hi, The attached circuit is the "standard" way to protect against accidental misconnection of the 3 phase half wave diode bridge. (ie a phase and neutral..." /> <meta property="og:description" content="Hi, The attached circuit is the "standard" way to protect against accidental misconnection of the 3 phase half wave diode bridge. (ie a phase and neutral getting accidentally swapped) But as can be seen, its a huge amount of componentry. Any lower_component_count ways? (LTspice and PNG attached)" /> <meta property="twitter:description" content="Hi, The attached circuit is the "standard" way to protect against accidental misconnection of the 3 phase half wave diode bridge. 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It may not display this or other websites correctly.<br />You should upgrade or use an <a href="https://www.google.com/chrome/" target="_blank" rel="noopener">alternative browser</a>.</div> <div class="p-body-header"> <div class="p-title "> <h1 class="p-title-value">Protection circuit for 3 phase bridge misconnection?</h1> </div> <div class="p-description"> <ul class="listInline listInline--bullet"> <li> <i class="fa--xf fal fa-user" aria-hidden="true" title="Thread starter"></i> <span class="u-srOnly">Thread starter</span> <a href="/members/flyback.55553/" class="username u-concealed" dir="auto" data-user-id="55553" data-xf-init="member-tooltip">Flyback</a> </li> <li> <i class="fa--xf fal fa-clock" aria-hidden="true" title="Start date"></i> <span class="u-srOnly">Start date</span> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/" class="u-concealed"><time class="u-dt" dir="auto" datetime="2024-09-28T10:15:32-0700" data-time="1727543732" data-date-string="Sep 28, 2024" data-time-string="10:15 AM" title="Sep 28, 2024 at 10:15 AM">Sep 28, 2024</time></a> </li> </ul> </div> </div> <div class="p-body-main p-body-main--withSidebar "> <div class="p-body-contentCol"></div> <div class="p-body-sidebarCol"></div> <div class="p-body-content"> <div class="p-body-pageContent"> <div class="block block--messages " data-xf-init="lightbox select-to-quote" data-message-selector=".js-post" data-lb-id="thread-166583"> <div class="block-outer"></div> <div class="block-outer js-threadStatusField"></div> <div class="block-container"> <div class="block-body"> <article class="message message--post js-post js-inlineModContainer " data-author="Flyback" data-content="post-1455710" id="js-post-1455710" > <span class="u-anchorTarget" id="post-1455710"></span> <div class="message-inner"> <div class="message-cell message-cell--user"> <section class="message-user" > <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/flyback.55553/" class="avatar avatar--m avatar--default avatar--default--dynamic" data-user-id="55553" data-xf-init="member-tooltip" style="background-color: #d67a5c; color: #662d1a"> <span class="avatar-u55553-m" role="img" aria-label="Flyback">F</span> </a> </div> </div> <div class="message-userDetails"> <h4 class="message-name"><a href="/members/flyback.55553/" class="username " dir="auto" data-user-id="55553" data-xf-init="member-tooltip">Flyback</a></h4> <h5 class="userTitle message-userTitle" dir="auto">Well-Known Member</h5> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455710" rel="nofollow" > <time class="u-dt" dir="auto" datetime="2024-09-28T10:15:32-0700" data-time="1727543732" data-date-string="Sep 28, 2024" data-time-string="10:15 AM" title="Sep 28, 2024 at 10:15 AM">Sep 28, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455710" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1455710/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455710" rel="nofollow"> #1 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1455710" data-lb-caption-desc="Flyback · Sep 28, 2024 at 10:15 AM"> <article class="message-body js-selectToQuote"> <div > <div class="bbWrapper">Hi,<br /> The attached circuit is the "standard" way to protect<br /> against accidental misconnection of the 3 phase half wave diode bridge.<br /> (ie a phase and neutral getting accidentally swapped)<br /> But as can be seen, its a huge amount of componentry.<br /> Any lower_component_count ways?<br /> <br /> (LTspice and PNG attached)</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> <section class="message-attachments"> <h4 class="block-textHeader">Attachments</h4> <ul class="attachmentList"> <li class="file file--linked"> <a class="u-anchorTarget" id="attachment-147231"></a> <script class="js-extraPhrases" type="application/json"> { "lightbox_close": "Close", "lightbox_next": "Next", "lightbox_previous": "Previous", "lightbox_error": "The requested content cannot be loaded. Please try again later.", "lightbox_start_slideshow": "Start slideshow", "lightbox_stop_slideshow": "Stop slideshow", "lightbox_full_screen": "Full screen", "lightbox_thumbnails": "Thumbnails", "lightbox_download": "Download", "lightbox_share": "Share", "lightbox_zoom": "Zoom", "lightbox_new_window": "New window", "lightbox_toggle_sidebar": "Toggle sidebar" } </script> <a class="file-preview js-lbImage" data-lb-sidebar-href="" data-lb-caption-extra-html="" href="/attachments/3-phase-diode-bridge-protection-png.147231/" target="_blank"> <img src="/data/attachments/136/136216-666669bd75f86fa2cefb41a9de52a626.jpg" alt="3 phase diode bridge protection.png" width="220" height="100" loading="lazy" /> </a> <div class="file-content"> <div class="file-info"> <span class="file-name" title="3 phase diode bridge protection.png">3 phase diode bridge protection.png</span> <div class="file-meta"> 52.3 KB · Views: 62 </div> </div> </div> </li> <li class="file file--linked"> <a class="u-anchorTarget" id="attachment-147232"></a> <a class="file-preview" href="/attachments/3-diode-bridge-protection-asc.147232/" target="_blank"> <span class="file-typeIcon"> <i class="fa--xf fal fa-file" aria-hidden="true"></i> </span> </a> <div class="file-content"> <div class="file-info"> <span class="file-name" title="3 diode bridge protection.asc">3 diode bridge protection.asc</span> <div class="file-meta"> 24.3 KB · Views: 42 </div> </div> </div> </li> </ul> </section> </div> </div> <footer class="message-footer"> <div class="reactionsBar js-reactionsList "> </div> <div class="js-historyTarget message-historyTarget toggleTarget" data-href="trigger-href"></div> </footer> </div> </div> </div> </article> </div> </div> </div> <div class="block block--messages" data-xf-init="" data-type="post" data-href="/inline-mod/" data-search-target="*"> <span class="u-anchorTarget" id="posts"></span> <div class="block-outer"><div class="block-outer-opposite"> <div class="tabs tabs--standalone tabs--standalone--small tabs--standalone--inline"> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/" class="tabs-tab is-active" rel="nofollow"> Sort by date </a> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/?order=vote_score" class="tabs-tab " rel="nofollow"> Sort by votes </a> </div> </div></div> <div class="block-container lbContainer" data-xf-init="lightbox select-to-quote" data-message-selector=".js-post" data-lb-id="thread-166583" data-lb-universal="0"> <div class="block-body js-replyNewMessageContainer"> <article class="message message--post js-post js-inlineModContainer " data-author="Diver300" data-content="post-1455711" id="js-post-1455711" itemscope itemtype="https://schema.org/Answer" itemid="https://www.electro-tech-online.com/posts/1455711/"> <meta itemprop="parentItem" itemscope itemid="https://www.electro-tech-online.com/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/" /> <span class="u-anchorTarget" id="post-1455711"></span> <div class="message-inner"> <div class="message-cell message-cell--user"> <section class="message-user" itemprop="author" itemscope itemtype="https://schema.org/Person" itemid="https://www.electro-tech-online.com/members/diver300.73824/"> <meta itemprop="url" content="https://www.electro-tech-online.com/members/diver300.73824/" /> <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/diver300.73824/" class="avatar avatar--m avatar--default avatar--default--dynamic" data-user-id="73824" data-xf-init="member-tooltip" style="background-color: #9933cc; color: #e0c2f0"> <span class="avatar-u73824-m" role="img" aria-label="Diver300">D</span> </a> </div> </div> <div class="message-userDetails"> <h4 class="message-name"><a href="/members/diver300.73824/" class="username " dir="auto" data-user-id="73824" data-xf-init="member-tooltip"><span itemprop="name">Diver300</span></a></h4> <h5 class="userTitle message-userTitle" dir="auto" itemprop="jobTitle">Well-Known Member</h5> <div class="userBanner userBanner userBanner--gray message-userBanner" itemprop="jobTitle"><span class="userBanner-before"></span><strong>Most Helpful Member</strong><span class="userBanner-after"></span></div> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455711" rel="nofollow" itemprop="url"> <time class="u-dt" dir="auto" datetime="2024-09-28T11:07:58-0700" data-time="1727546878" data-date-string="Sep 28, 2024" data-time-string="11:07 AM" title="Sep 28, 2024 at 11:07 AM" itemprop="datePublished">Sep 28, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455711" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1455711/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455711" rel="nofollow"> #2 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1455711" data-lb-caption-desc="Diver300 · Sep 28, 2024 at 11:07 AM"> <article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper">I would use a microcontroller.<br /> <br /> Each phase would be connected with a potential divider, but a three-resistor potential divider. There would be a low value resistor between the analog input and ground, and an equal resistor between the analog input and +5 V (assuming a 5 V supplied microcontroller). The final resistor would be a high value resistor between the phase and the analog input. A total of 9 resistors for 3 phases.<br /> <br /> So each phase would be measured, the peak negative voltage giving near 0 V on the analog input of the microcontroller, and the peak positive voltage giving near 5 V on the analog input.<br /> <br /> With that, the processor can work out if all the voltages are correct and if the phase rotation is correct.<br /> <br /> I did something very similar to check phase rotation using a PIC16F877 about 20 years ago. In that case the processor had to do a load of other stuff which is why I used a microcontroller with so many pins. There are 8 pin microcontrollers with 5 analog channels that could do what you want.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> <aside class="message-signature"> <div class="bbWrapper"><a href="http://twitter.com/mtrak_uk" target="_blank" class="link link--external" rel="nofollow ugc noopener">http://twitter.com/mtrak_uk</a></div> </aside> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList "> </div> <div class="js-historyTarget message-historyTarget toggleTarget" data-href="trigger-href"></div> </footer> </div> </div> <div class="message-cell message-cell--vote"> <div class="message-column"> <div class="contentVote js-contentVote " data-xf-init="content-vote" 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<section class="message-user" itemprop="author" itemscope itemtype="https://schema.org/Person" itemid="https://www.electro-tech-online.com/members/flyback.55553/"> <meta itemprop="url" content="https://www.electro-tech-online.com/members/flyback.55553/" /> <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/flyback.55553/" class="avatar avatar--m avatar--default avatar--default--dynamic" data-user-id="55553" data-xf-init="member-tooltip" style="background-color: #d67a5c; color: #662d1a"> <span class="avatar-u55553-m" role="img" aria-label="Flyback">F</span> </a> </div> </div> <div class="message-userDetails"> <h4 class="message-name"><a href="/members/flyback.55553/" class="username " dir="auto" data-user-id="55553" data-xf-init="member-tooltip"><span itemprop="name">Flyback</span></a></h4> <h5 class="userTitle message-userTitle" dir="auto" itemprop="jobTitle">Well-Known Member</h5> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455715" rel="nofollow" itemprop="url"> <time class="u-dt" dir="auto" datetime="2024-09-28T12:39:37-0700" data-time="1727552377" data-date-string="Sep 28, 2024" data-time-string="12:39 PM" title="Sep 28, 2024 at 12:39 PM" itemprop="datePublished">Sep 28, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455715" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1455715/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455715" rel="nofollow"> #3 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1455715" data-lb-caption-desc="Flyback · Sep 28, 2024 at 12:39 PM"> <article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper"><blockquote data-attributes="" data-quote="" data-source="" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> So each phase would be measured, the peak negative voltage giving near 0 V on the analog input of the microcontroller, and the peak positive voltage giving near 5 V on the analog input. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote> <blockquote data-attributes="" data-quote="" data-source="" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Thanks, the phases are each 90-265VAC....(each will be same voltage but anywhere between 90-265VAC). </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>.......Sorry i dont know why it put my words in quotes.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList "> </div> <div class="js-historyTarget message-historyTarget toggleTarget" 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data-user-id="73824" data-xf-init="member-tooltip"><span itemprop="name">Diver300</span></a></h4> <h5 class="userTitle message-userTitle" dir="auto" itemprop="jobTitle">Well-Known Member</h5> <div class="userBanner userBanner userBanner--gray message-userBanner" itemprop="jobTitle"><span class="userBanner-before"></span><strong>Most Helpful Member</strong><span class="userBanner-after"></span></div> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455719" rel="nofollow" itemprop="url"> <time class="u-dt" dir="auto" datetime="2024-09-28T14:40:53-0700" data-time="1727559653" data-date-string="Sep 28, 2024" data-time-string="2:40 PM" title="Sep 28, 2024 at 2:40 PM" itemprop="datePublished">Sep 28, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455719" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1455719/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455719" rel="nofollow"> #4 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1455719" data-lb-caption-desc="Diver300 · Sep 28, 2024 at 2:40 PM"> <article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper">If you are allowing for the one of the phases to be swapped with neutral, the measured voltage could be up to about 650 V peak, the peak voltage between phases on a 3 phase 265 V system. That just means that you need a high-value resistor in the potential divider. 90 Vac signals connected correctly will be a bit small but the voltage will still be about 20% of the range of the ADC.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> <aside class="message-signature"> <div class="bbWrapper"><a href="http://twitter.com/mtrak_uk" target="_blank" class="link link--external" rel="nofollow ugc noopener">http://twitter.com/mtrak_uk</a></div> </aside> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList is-active"> <ul class="reactionSummary"> <li><span class="reaction reaction--small reaction--1" data-reaction-id="1"><i aria-hidden="true"></i><img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="reaction-sprite js-reaction" alt="Like" title="Like" /></span></li> </ul> <span class="u-srOnly">Reactions:</span> <a class="reactionsBar-link" href="/posts/1455719/reactions" data-xf-click="overlay" data-cache="false" rel="nofollow"><bdi>Flyback</bdi></a> </div> <div class="js-historyTarget message-historyTarget toggleTarget" data-href="trigger-href"></div> </footer> </div> </div> <div class="message-cell message-cell--vote"> <div class="message-column"> <div class="contentVote js-contentVote " data-xf-init="content-vote" data-content-id="post-1455719"> <meta itemprop="upvoteCount" content="0" /> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--up " data-vote="up"><span class="u-srOnly">Upvote</span></a> <span class="contentVote-score js-voteCount" data-score="0">0</span> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--down " data-vote="down"><span class="u-srOnly">Downvote</span></a> </div> </div> </div> </div> </article> <article class="message message--post js-post js-inlineModContainer " data-author="MrAl" data-content="post-1455727" id="js-post-1455727" itemscope itemtype="https://schema.org/Answer" itemid="https://www.electro-tech-online.com/posts/1455727/"> <meta itemprop="parentItem" itemscope itemid="https://www.electro-tech-online.com/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/" /> <span class="u-anchorTarget" id="post-1455727"></span> <div class="message-inner"> <div class="message-cell message-cell--user"> <section class="message-user" itemprop="author" itemscope itemtype="https://schema.org/Person" itemid="https://www.electro-tech-online.com/members/mral.97462/"> <meta itemprop="url" content="https://www.electro-tech-online.com/members/mral.97462/" /> <div class="message-avatar "> <div class="message-avatar-wrapper"> <a href="/members/mral.97462/" class="avatar avatar--m avatar--default avatar--default--dynamic" data-user-id="97462" data-xf-init="member-tooltip" style="background-color: #cc3399; color: #f0c2e0"> <span class="avatar-u97462-m" role="img" aria-label="MrAl">M</span> </a> </div> </div> <div class="message-userDetails"> <h4 class="message-name"><a href="/members/mral.97462/" class="username " dir="auto" data-user-id="97462" data-xf-init="member-tooltip"><span itemprop="name">MrAl</span></a></h4> <h5 class="userTitle message-userTitle" dir="auto" itemprop="jobTitle">Well-Known Member</h5> <div class="userBanner userBanner userBanner--gray message-userBanner" itemprop="jobTitle"><span class="userBanner-before"></span><strong>Most Helpful Member</strong><span class="userBanner-after"></span></div> </div> <span class="message-userArrow"></span> </section> </div> <div class="message-cell message-cell--main"> <div class="message-main js-quickEditTarget"> <header class="message-attribution message-attribution--split"> <ul class="message-attribution-main listInline "> <li class="u-concealed"> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455727" rel="nofollow" itemprop="url"> <time class="u-dt" dir="auto" datetime="2024-09-29T03:36:11-0700" data-time="1727606171" data-date-string="Sep 29, 2024" data-time-string="3:36 AM" title="Sep 29, 2024 at 3:36 AM" itemprop="datePublished">Sep 29, 2024</time> </a> </li> </ul> <ul class="message-attribution-opposite message-attribution-opposite--list "> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455727" class="message-attribution-gadget" data-xf-init="share-tooltip" data-href="/posts/1455727/share" aria-label="Share" rel="nofollow"> <i class="fa--xf fal fa-share-alt" aria-hidden="true"></i> </a> </li> <li> <a href="/threads/protection-circuit-for-3-phase-bridge-misconnection.166583/post-1455727" rel="nofollow"> #5 </a> </li> </ul> </header> <div class="message-content js-messageContent"> <div class="message-userContent lbContainer js-lbContainer " data-lb-id="post-1455727" data-lb-caption-desc="MrAl · Sep 29, 2024 at 3:36 AM"> <article class="message-body js-selectToQuote"> <div itemprop="text"> <div class="bbWrapper"><blockquote data-attributes="member: 55553" data-quote="Flyback" data-source="post: 1455710" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=1455710" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-1455710">Flyback said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Hi,<br /> The attached circuit is the "standard" way to protect<br /> against accidental misconnection of the 3 phase half wave diode bridge.<br /> (ie a phase and neutral getting accidentally swapped)<br /> But as can be seen, its a huge amount of componentry.<br /> Any lower_component_count ways?<br /> <br /> (LTspice and PNG attached) </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> The way a lot of power electronics is done that involves connections that are not right is the connections are tested BEFORE any connection is actually made.<br /> <br /> In other words, the phases and rotations are checked before the power is connected, in this case to the bridge.<br /> This would involve a heavy duty switch in some cases. the switch is open for the test, and only after the test indicates the phases are correct, then the switch is closed.<br /> <br /> I suppose you can make this automatic by using a contactor and measuring circuits, and a delay. First the measurements are made, then a decision is made to either close the contactor or leave it open and warn the user, then possibly close the contactor. If the only problem that can come up is the exchange of one of the phases and the neutral wire, then you can probably get away with measuring all the voltages and use a delay that is long enough to get the proper measurements. If you need to detect phase rotation then the measurement circuits have to be upgrade.<br /> Note that it would be better to use a three phase contactor BEFORE the bridge not a single relay after the bridge.<br /> <br /> Add some fuses and it should be ok.</div> </div> <div class="js-selectToQuoteEnd"> </div> </article> </div> <aside class="message-signature"> <div class="bbWrapper">One test is worth a thousand expert opinions, but one expert specification is worth a thousand tests.<br /> Mathematics is the shortcut to understanding nature.<br /> If i miss something you posted or something you think is important, feel free to PM me.</div> </aside> </div> <footer class="message-footer"> <div class="message-microdata" itemprop="interactionStatistic" itemtype="https://schema.org/InteractionCounter" itemscope> <meta itemprop="userInteractionCount" content="0" /> <meta itemprop="interactionType" content="https://schema.org/LikeAction" /> </div> <div class="reactionsBar js-reactionsList is-active"> <ul class="reactionSummary"> <li><span class="reaction reaction--small reaction--1" data-reaction-id="1"><i aria-hidden="true"></i><img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="reaction-sprite js-reaction" alt="Like" title="Like" /></span></li> </ul> <span class="u-srOnly">Reactions:</span> <a class="reactionsBar-link" href="/posts/1455727/reactions" data-xf-click="overlay" data-cache="false" rel="nofollow"><bdi>Flyback</bdi></a> </div> <div class="js-historyTarget message-historyTarget toggleTarget" data-href="trigger-href"></div> </footer> </div> </div> <div class="message-cell message-cell--vote"> <div class="message-column"> <div class="contentVote js-contentVote " data-xf-init="content-vote" data-content-id="post-1455727"> <meta itemprop="upvoteCount" content="0" /> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--up " data-vote="up"><span class="u-srOnly">Upvote</span></a> <span class="contentVote-score js-voteCount" data-score="0">0</span> <a href="javascript:" class="contentVote-vote is-disabled contentVote-vote--down " data-vote="down"><span class="u-srOnly">Downvote</span></a> </div> </div> </div> </div> </article> </div> </div> <div class="block-outer block-outer--after"> <div class="block-outer-opposite"> <a href="/login/" class="button--link button--wrap button" data-xf-click="overlay"><span class="button-text"> You must log in or register to reply here. </span></a> </div> </div> </div> <div class="inContentAd"><div id='div-gpt-eto_thread1'> <script> googletag.cmd.push(function() { googletag.display('div-gpt-eto_thread1'); 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First the measurements are made, then a decision is made to either close the contactor or leave it open and warn the user, then possibly close the contactor. If the only problem that can come up is the exchange of one of the phases and the neutral wire, then you can probably get away with measuring all the voltages and use a delay that is long enough to get the proper measurements. If you need to detect phase rotation then the measurement circuits have to be upgrade.\nNote that it would be better to use a three phase contactor BEFORE the bridge not a single relay after the bridge.\n\nAdd some fuses and it should be ok.", "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/mral.97462/", "name": "MrAl", "url": "https://www.electro-tech-online.com/members/mral.97462/" } }, { "@type": "Answer", "datePublished": "2024-09-28T21:40:53+00:00", "url": "https://www.electro-tech-online.com/posts/1455719/", "text": "If you are allowing for the one of the phases to be swapped with neutral, the measured voltage could be up to about 650 V peak, the peak voltage between phases on a 3 phase 265 V system. That just means that you need a high-value resistor in the potential divider. 90 Vac signals connected correctly will be a bit small but the voltage will still be about 20% of the range of the ADC.", "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/diver300.73824/", "name": "Diver300", "url": "https://www.electro-tech-online.com/members/diver300.73824/" } }, { "@type": "Answer", "datePublished": "2024-09-28T19:39:37+00:00", "url": "https://www.electro-tech-online.com/posts/1455715/", "text": "So each phase would be measured, the peak negative voltage giving near 0 V on the analog input of the microcontroller, and the peak positive voltage giving near 5 V on the analog input.\n\n\n\n\n\n\n\n\nThanks, the phases are each 90-265VAC....(each will be same voltage but anywhere between 90-265VAC).\n\n.......Sorry i dont know why it put my words in quotes.", "upvoteCount": 0, "author": { "@type": "Person", "@id": "https://www.electro-tech-online.com/members/flyback.55553/", "name": "Flyback", "url": "https://www.electro-tech-online.com/members/flyback.55553/" } } ] }, "publisher": { "@type": "Organization", "name": "Electronics Forum (Circuits, Projects and Microcontrollers)", "description": "An electronics forum to talk all about circuits and projects.", "url": "https://www.electro-tech-online.com" } } </script>  <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-MMC9PJ9" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>   <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-KLX5R59" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>  <script> $(function(){ var notice = $('.xb-welcome-notice'); if(notice.length){ var cookie = XF.Cookie.get('hide_welcome_notice'); if(!cookie){ XF.Cookie.set('hide_welcome_notice', Date.now()); notice.show(); } else if ((Date.now() - cookie) > 8.64e+7){ XF.Cookie.set('hide_welcome_notice', Date.now()); notice.show(); } else { notice.hide(); } } }); </script> </div> </body> </html>

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Protection circuit for 3 phase bridge misconnection? | Electronics Forum (Circuits, Projects and Microcontrollers)