{"id":1339,"date":"2018-03-21T18:34:25","date_gmt":"2018-03-21T22:34:25","guid":{"rendered":"\/?p=1339"},"modified":"2018-11-12T13:51:36","modified_gmt":"2018-11-12T18:51:36","slug":"trigger-polarity-why-is-it-so-important","status":"publish","type":"post","link":"https:\/\/ricksmotorsportelectrics.com\/blog\/trigger-polarity-why-is-it-so-important\/","title":{"rendered":"Trigger Polarity – Why is it so important?"},"content":{"rendered":"

It’s not uncommon for us to receive a question on a no-spark or mis-timed spark problem, and often the solution is to switch the position of the trigger wires<\/strong>.\u00a0 This begs the question, why is the position of these wires so important?\u00a0 We’ll get into that here and hopefully provide some valuable insight on these components themselves.<\/p>\n

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Rick’s trigger coil 21-528<\/a><\/figcaption><\/figure>\n
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Rick’s Trigger Coil 21-529<\/a><\/figcaption><\/figure>\n

First, what is a \u201ctrigger\u201d?\u00a0 For one thing, it can go by many different names such as a \u201cpickup coil\u201d, \u201ccrank position sensor\u201d, \u201csignal generator\u201d, etc.\u00a0 It is a part, usually consisting of a metal base plate with two screw-holes and a raised plastic or potted portion with a magnet in it that is bolted to the cover next to the flywheel.\u00a0 Wound around this magnetic core inside the trigger is a coil of very thin wire.\u00a0 Here is a cross-section of a typical trigger such as Rick’s part# 21-502:<\/p>\n

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The magnetic face is designed to work with a section of the outside circumference of the flywheel known as the \u201creluctor\u201d.\u00a0 This is simply a raised portion of metal that will pass very close to the magnet.\u00a0 When it does, it will create a fluctuation in the field of the magnet inside the trigger.\u00a0 This fluctuation will in turn induce a small electromagnetic potential difference between the two ends of the coil (this is referred to as the \u201cHall Effect\u201d).\u00a0 Since the flywheel is bolted to the crankshaft and the changing field only occurs when the reluctor is passing the magnet, the signal from this will always be at a particular degree of crankshaft rotation.\u00a0 This is how the CDI times the ignition.<\/p>\n

Inside the CDI box is a capacitor across which a static charge will build up due to applied voltage from either the stator’s source coil (AC-CDI, \u201cstator ignition) or the battery (DC-CDI, \u201cbattery ignition).\u00a0 For more detailed info on CDI boxes. check out THIS blog post<\/a>.\u00a0 <\/em>This static charge will remain across the capacitor until it is discharged to the primary side of the ignition coil (hence C<\/u>apacitor D<\/u>ischarge I<\/u>gnition).\u00a0 This timing is controlled by a semiconductor component called a thyristor, or SCR (S<\/u>ilicon C<\/u>ontrolled R<\/u>ectifier).\u00a0 This component is in an \u201coff\u201d state naturally; it must be \u201cturned on\u201d by applying correct voltage to its gate terminal.<\/p>\n

The trigger is connected to the gate, and the signal being generated is responsible for opening and closing the gate.\u00a0 As a semiconductor device, the SCR requires not only the correct voltage<\/em> applied to the gate but the correct polarity<\/em> as well.\u00a0 If it’s backward, the gate will actually increase in strength when it should be decreasing.\u00a0 Doing this causes significant timing failures, if not stopping the output altogether (this will vary depending on the vehicle).<\/p>\n

 <\/p>\n

Hopefully this answers your questions on why the position of the wires matters so much on the trigger coils!<\/p>\n","protected":false},"excerpt":{"rendered":"

It’s not uncommon for us to receive a question on a no-spark or mis-timed spark problem, and often the solution is to switch the position of the trigger wires.\u00a0 This begs the question, why is the position of these wires so important?\u00a0 We’ll get into that here and hopefully provide some valuable insight on these…<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[133,5,62,99,154,116,136,131],"class_list":["post-1339","post","type-post","status-publish","format-standard","hentry","category-new-from-ricks","tag-atvs","tag-how-to","tag-howto","tag-motorcycles","tag-off-road","tag-snow-mobiles","tag-tech-tip","tag-tech-tips"],"_links":{"self":[{"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/posts\/1339","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/comments?post=1339"}],"version-history":[{"count":4,"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/posts\/1339\/revisions"}],"predecessor-version":[{"id":1361,"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/posts\/1339\/revisions\/1361"}],"wp:attachment":[{"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/media?parent=1339"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/categories?post=1339"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ricksmotorsportelectrics.com\/blog\/wp-json\/wp\/v2\/tags?post=1339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}