{"id":15494,"date":"2026-01-06T10:46:30","date_gmt":"2026-01-06T02:46:30","guid":{"rendered":"http:\/\/www.erun-tech.com\/?post_type=dt_portfolio&#038;p=15494"},"modified":"2026-01-06T10:59:44","modified_gmt":"2026-01-06T02:59:44","slug":"zhukaiguanjiqikongzhihuiludeweihuhexiuli","status":"publish","type":"dt_portfolio","link":"http:\/\/www.erun-tech.com\/en\/project\/zhukaiguanjiqikongzhihuiludeweihuhexiuli","title":{"rendered":"Main Switch and Its Control Circuit Maintenance and Repair"},"content":{"rendered":"<p>&nbsp;<\/p>\n<style>\n        :root {<br \/>\n            --primary-blue: #004a99;<br \/>\n            --secondary-blue: #0073e6;<br \/>\n            --accent-gold: #b8860b;<br \/>\n            --bg-light: #f8f9fa;<br \/>\n            --border-color: #dee2e6;<br \/>\n            --text-main: #333;<br \/>\n        }<\/p>\n<p>        body {<br \/>\n            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif, \"PingFang SC\", \"Microsoft YaHei\";<br \/>\n            line-height: 1.7;<br \/>\n            color: var(--text-main);<br \/>\n            background-color: #f0f2f5;<br \/>\n            margin: 0;<br \/>\n            display: flex;<br \/>\n        }<\/p>\n<p>        \/* \u4fa7\u8fb9\u5bfc\u822a *\/<br \/>\n        nav {<br \/>\n            width: 260px;<br \/>\n            background: var(--primary-blue);<br \/>\n            color: white;<br \/>\n            height: 100vh;<br \/>\n            position: fixed;<br \/>\n            padding-top: 20px;<br \/>\n            overflow-y: auto;<br \/>\n        }<\/p>\n<p>        nav h4 { text-align: center; 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}<br \/>\n            main { margin-left: 0; padding: 20px; }<br \/>\n        }<br \/>\n    <\/style>\n<p>&nbsp;<\/p>\n<nav>\n<h4>Content Navigation<\/h4>\n<p><a href=\"#section1\">I. Analysis of DW98 protection principle<\/a><br \/>\n<a href=\"#sub1_1\">1.1 Undervoltage delay trip protection<\/a><br \/>\n<a href=\"#sub1_2\">1.2 Overcurrent trip protection<\/a><br \/>\n<a href=\"#section2\">II. Main switch routine maintenance<\/a><br \/>\n<a href=\"#section3\">III. Common failures and repairs<\/a><\/p>\n<\/nav>\n<p>&nbsp;<\/p>\n<div class=\"container\">\n<h1>Main Switch and Its Control Circuit Maintenance and Repair<\/h1>\n<h2 id=\"section1\">I. Principle analysis of marine main switch control circuit protection function<\/h2>\n<p>\u4ee5 <strong>DW98 Automatic Air Circuit Breaker<\/strong> For example. This model adopts a semiconductor detent as a protection device and is capable of realizing four protection functions: undervoltage delay, mega short-circuit instantaneous, short-circuit short-delay and overload long-delay.<\/p>\n<h3 id=\"sub1_1\"><img decoding=\"async\" class=\"alignnone size-full wp-image-15495\" title=\"a76652adc3cca11fd4b1bd18e755a2c9\" src=\"http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9.png\" alt=\"a76652adc3cca11fd4b1bd18e755a2c9\" width=\"1366\" height=\"966\" srcset=\"http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9.png 1366w, http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9-300x212.png 300w, http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9-1024x724.png 1024w, http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9-768x543.png 768w, http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9-18x12.png 18w, http:\/\/www.erun-tech.com\/wp-content\/uploads\/2026\/01\/a76652adc3cca11fd4b1bd18e755a2c9-600x424.png 600w\" sizes=\"(max-width: 1366px) 100vw, 1366px\" \/>1. Undervoltage delay trip protection<\/h3>\n<p><strong>Power supply:<\/strong> The generator voltage is stepped down by transformer B\u2081, rectified by ZL bridge, filtered by Rz\/C\u2088 and regulated by W\u2085 to provide the transistor DC regulated operating power.<\/p>\n<p><strong>Signal formation:<\/strong> The voltage UA\u1d04 is stepped down to 15V via the first VSV of B\u2081, half-wave rectified by D\u2081\u2085 and filtered by C\u2085, and a weak DC voltage control signal is extracted from the R\u2082\u2080 voltage divider. This signal is proportional to the generator voltage.<\/p>\n<div class=\"spec-box\"><strong>Action Logic:<\/strong><\/p>\n<ul>\n<li><strong>Normal state:<\/strong> R\u2082\u2080 Voltage breakdown W\u2084, BG\u2085 saturated conduction, shorted time-delay capacitor C\u2086, no signal in exit circuit.<\/li>\n<li><strong>Undervoltage condition:<\/strong> When the voltage falls below the set value (e.g. 65% U\u2080), W\u2084 cuts off, BG\u2085 cuts off, and the power supply charges C\u2086\/C\u2087 via R\u2082\/R\u2082\u2082.<\/li>\n<li><strong>Delay Selection:<\/strong> 0.5s, 1s, 3s, 5s When the capacitive voltage reaches the peak value of the BT of the single junction transistor, the SCR conducts, and the voltage-loss detector S trips without power.<\/li>\n<\/ul>\n<\/div>\n<h3 id=\"sub1_2\">2. Overcurrent trip protection<\/h3>\n<p>The three-phase current is detected by the current transformers LH\u2081~LH\u2083, rectified by bridge rectifier and filtered, and then converted into a weak DC signal by three parallel voltage dividers:<\/p>\n<ul>\n<li><strong>Extra large short circuit transient:<\/strong> R\u2082\u2082, R\u2082\u2083, R\u2083 signal detection. Utilizing the current-failure protection, the setting value is usually in the range of (5~10) I<sub>K<\/sub>\u3002<\/li>\n<li><strong>Short circuit short delay:<\/strong> R\u2084, R\u2082\u2087, R\u2085 signal detection. With time limit characteristic, delay time 0.2~0.6s, set value (3~5) I<sub>K<\/sub>\u3002<\/li>\n<li><strong>Overload long delay:<\/strong> R\u2082\u2088, R\u2086 signal detection. Utilizing the inverse time characteristic of C\u2083 charging (short delay time for large overload), the set value (1.0~2.5) I<sub>K<\/sub>\u3002<\/li>\n<\/ul>\n<h2 id=\"section2\">II. Main switch routine maintenance<\/h2>\n<p>The operating status of the main switch is divided into:<strong>working position<\/strong>(Main contact on),<strong>Test position<\/strong>(main circuit disconnected, secondary circuit connected) and<strong>Disconnect Position<\/strong>(complete security isolation).<\/p>\n<h3>1. Regular maintenance norms<\/h3>\n<table>\n<thead>\n<tr>\n<th>cyclicality<\/th>\n<th>Content of the project<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>every six months<\/td>\n<td>Lubricate moving parts; tighten screws; measure contact thickness (down to 1\/3 for replacement); clean interrupter; check closing coil.<\/td>\n<\/tr>\n<tr>\n<td>biennial<\/td>\n<td>Calibrate the set value of the disconnect current and the delay time.<\/td>\n<\/tr>\n<tr>\n<td>late in life<\/td>\n<td>If 3\/4 of the mechanical life has been used, the calibration should be done annually.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>2. Maintenance checklist<\/h3>\n<ul class=\"check-list\">\n<li><strong>Appearance check:<\/strong> Verify that there are no cracks, corrosion or signs of overheating in the enclosure; and that the handles and buttons are flexible.<\/li>\n<li><strong>Clean and lubricate:<\/strong> Use precision electrical cleaners to remove contact oxidation; apply special grease to drive components.<\/li>\n<li><strong>Insulation testing:<\/strong> Measured with a megohmmeter (500V\/1000V), the insulation resistance should be <strong>&gt; 1 M\u03a9<\/strong>\u3002<\/li>\n<li><strong>Functional testing:<\/strong> Verify the smoothness of manual opening and closing and the sensitivity of analog protection disconnection.<\/li>\n<\/ul>\n<h2 id=\"section3\">III. Common Failures and Repair<\/h2>\n<div class=\"fault-item\">\n<p class=\"fault-title\">1. Unable to close<\/p>\n<p><strong>Mechanical:<\/strong> Check for failed energy storage spring or seized mechanism.<br \/>\n<strong>Electrical:<\/strong> Test the closing coil resistance (tens to hundreds of ohms) and the control supply voltage.<\/p>\n<\/div>\n<div class=\"fault-item\">\n<p class=\"fault-title\">2. Abnormal tripping<\/p>\n<p><strong>Misbehavior:<\/strong> Improperly tuned relays or external interference.<br \/>\n<strong>Real Failure:<\/strong> Troubleshoot load side ground or short circuit.<\/p>\n<\/div>\n<div class=\"fault-item\">\n<p class=\"fault-title\">3. Contact ablation<\/p>\n<p>Minor abrasion can be polished with sandpaper; in severe cases, the contacts must be replaced to prevent heat from causing a fire.<\/p>\n<\/div>\n<div class=\"fault-item\">\n<p class=\"fault-title\">4. Control circuit troubleshooting<\/p>\n<p>Use a multimeter to check the terminal rows and plugs section by section using the on-off block. A short circuit to ground can be<strong>segmentation fault<\/strong>Positioning.<\/p>\n<\/div>\n<\/div>\n<footer>Marine Electronics Technician (ETO) Professional Technical Reference Manual - 2026 Edition<\/p>\n<\/footer>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>","protected":false},"excerpt":{"rendered":"<p>&nbsp; &nbsp; Table of Contents I. Analysis of DW98 Protection Principles 1.1 Undervoltage Delayed Trip Protection 1.2 Overcurrent Trip Protection...<\/p>","protected":false},"author":1,"featured_media":15497,"comment_status":"open","ping_status":"closed","template":"","dt_portfolio_category":[891],"dt_portfolio_tags":[],"class_list":["post-15494","dt_portfolio","type-dt_portfolio","status-publish","has-post-thumbnail","hentry","dt_portfolio_category-dianzidianqiyuanshicaopinggukecheng","dt_portfolio_category-891","description-off"],"_links":{"self":[{"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/dt_portfolio\/15494","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/dt_portfolio"}],"about":[{"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/types\/dt_portfolio"}],"author":[{"embeddable":true,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/comments?post=15494"}],"version-history":[{"count":2,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/dt_portfolio\/15494\/revisions"}],"predecessor-version":[{"id":15498,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/dt_portfolio\/15494\/revisions\/15498"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/media\/15497"}],"wp:attachment":[{"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/media?parent=15494"}],"wp:term":[{"taxonomy":"dt_portfolio_category","embeddable":true,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/dt_portfolio_category?post=15494"},{"taxonomy":"dt_portfolio_tags","embeddable":true,"href":"http:\/\/www.erun-tech.com\/en\/wp-json\/wp\/v2\/dt_portfolio_tags?post=15494"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}