# Question from the young and inexperienced

**URL:** <https://community.electricforum.com/t/question-from-the-young-and-inexperienced/584>\
**Category:** Conversion Kits\
**Created:** [March 20, 2008, 7:44pm UTC](https://community.electricforum.com/t/question-from-the-young-and-inexperienced/584 "2008-03-20T19:44:41Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Sir\_Joab](https://avatars.discourse-cdn.com/v4/letter/s/7bcc69/32.png) [@Sir\_Joab](https://community.electricforum.com/u/Sir_Joab)\
**Post date:** [March 20, 2008, 7:44pm UTC](https://community.electricforum.com/t/question-from-the-young-and-inexperienced/584/1 "2008-03-20T19:44:41Z")

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Hey guys,  
I’ve grown up working on cars, and I’m studying electrical engineering, but I’m a total newbie when it comes to putting the two together in an electric car.

Here’s my first question: What is a Contactor, what is it used for? Is it basically a giant relay?

Thanks.

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**Author:** ![Twilly](https://avatars.discourse-cdn.com/v4/letter/t/45deac/32.png) [@Twilly](https://community.electricforum.com/u/Twilly)\
**Post date:** [March 20, 2008, 9:26pm UTC](https://community.electricforum.com/t/question-from-the-young-and-inexperienced/584/2 "2008-03-20T21:26:17Z")

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You are correct, just a big relay

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**Author:** ![Sir\_Joab](https://avatars.discourse-cdn.com/v4/letter/s/7bcc69/32.png) [@Sir\_Joab](https://community.electricforum.com/u/Sir_Joab)\
**Post date:** [March 20, 2008, 9:34pm UTC](https://community.electricforum.com/t/question-from-the-young-and-inexperienced/584/3 "2008-03-20T21:34:18Z")

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Is it used for reversing the polarity of the power to the motor, or is it just a “main-switch”?

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**Author:** ![Twilly](https://avatars.discourse-cdn.com/v4/letter/t/45deac/32.png) [@Twilly](https://community.electricforum.com/u/Twilly)\
**Post date:** [March 22, 2008, 11:53am UTC](https://community.electricforum.com/t/question-from-the-young-and-inexperienced/584/4 "2008-03-22T11:53:17Z")

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It can be both…