{"id":3102,"date":"2024-08-26T20:44:40","date_gmt":"2024-08-26T20:44:40","guid":{"rendered":"https:\/\/workhouse.sweetdishy.com\/?p=3102"},"modified":"2024-08-26T20:44:41","modified_gmt":"2024-08-26T20:44:41","slug":"metal-oxide-varistors","status":"publish","type":"post","link":"https:\/\/workhouse.sweetdishy.com\/index.php\/2024\/08\/26\/metal-oxide-varistors\/","title":{"rendered":"Metal Oxide Varistors"},"content":{"rendered":"\n<p id=\"P0600\">Metal oxide varistors (MOVs) are components that have a nonlinear V\/I characteristic. In the case of varistors used for voltage protection, the voltage varies but little over a very wide range of current. The types used for power electronics are made by pressing and sintering wafers of zinc oxide ceramic with the characteristics determined by the process, the diameter, and the thickness. These devices are available in sizes from those suitable for surface mounting on PC boards to those for large station-type lightning arresters. The range spans sizes from a few millimeters to 90&nbsp;mm in diameter.<\/p>\n\n\n\n<p id=\"P0610\">The V\/I curve for a typical 60-mm dia., 480\u00a0V rated MOV is shown in\u00a0Figure 15.7. Note that the current is only 1\u00a0A at 1000\u00a0V peak and virtually zero at the 680\u00a0V peak in a 480\u00a0V circuit. However, it will limit the peak voltage to about 1200\u00a0V at 1000\u00a0A. This means it will protect a 1200\u00a0V SCR or other semiconductor from peak transient currents as high as 1000\u00a0A. MOVs are generally applied at their nominal rms voltage rating and are expected to clamp transients to a peak voltage of 2.5 times their rms rating.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/learning.oreilly.com\/api\/v2\/epubs\/urn:orm:book:9781856175289\/files\/images\/F000159gr7.jpg\" alt=\"image\"\/><\/figure>\n\n\n\n<p><strong>Figure 15.7<\/strong>&nbsp;480&nbsp;V, 60-mm MOV characteristic<\/p>\n\n\n\n<p id=\"P0620\">MOVs have little power dissipation capability, and they can be easily destroyed by repetitive transients such as produced by SCR commutation. MOV catalogs show the<a><\/a>&nbsp;lifetime characteristics as a function of the current magnitude and duration. When used for suppressing breaker chop, for example, the maximum lifetime exposure should be calculated so that a suitably sized MOV can be specified.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Metal oxide varistors (MOVs) are components that have a nonlinear V\/I characteristic. In the case of varistors used for voltage protection, the voltage varies but little over a very wide range of current. The types used for power electronics are made by pressing and sintering wafers of zinc oxide ceramic with the characteristics determined by [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3103,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[420],"tags":[],"class_list":["post-3102","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-power-electronics"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/08\/F000159gr7.jpg","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/3102","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=3102"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/3102\/revisions"}],"predecessor-version":[{"id":3104,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/3102\/revisions\/3104"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/3103"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=3102"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=3102"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=3102"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}