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Unread 20-02-2011, 22:57
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Spud Gun Division
AKA: Leav Oz-Ari
FRC #3316 (D-Bug)
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Re: Possibly Ruined All Four Jaguars

Quote:
Originally Posted by somenerd View Post
Through a series of unfortunate events, our jaguars controlling our CIM motors were wired incorrectly. V+ and V- was inserted into M+ and M- and vice versa. So the robot went crazy when we simply flipped the switch to turn it on. One jaguar caught fire internally. (Which we initially attributed to metal shavings).
When correctly wired, the jaguars still allow current to pass through them when their is no signal present, effectively landing us in the same situation were we had them wired incorrectly.
In addition, two more jaguars had their magic white smoke leave them.
In hindsight, with current running in the opposite direction unimpeded, plus the white smoke (and fire), I think all of 4 jag's connected to the CIMs are ruined, even though they still power up.
  1. Is this assessment correct?
  2. How would I test the jaguars with a multimeter? I'm thinking about testing resistance across V+ and M+
  3. Also, I'm thinking about opening the jaguars up to inspect the damage. Good idea?
One of our mentors is a power EE, but is out of town on personal business. When he gets back, I'm going to ask for his opinion on our situation.
I made the same mistake my rookie year, except it was Victors.

Expensive mistake, but no team I have ever been on has ever repeated it. every electrical board gets inspected twice (at least) before being turned on.

I think the jags are done for, unless you do as reuven suggested in which case you could probably fix them (especially if you have an EE mentor). I wouldn't consider them "competition worthy" if I were you, but they are definitely worth the effort.
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"We choose to build robots this season and do the other things; Not because they are easy, but because they are hard."
-Paraphrasing JFK

Participated in FIRST as a student: 2005-2006 (But still learning every season!)
Mentor: 2008 - ? (Team 2630 2008-2011, and Team 3316 since 2013)
Engineer: 2011 - ? (B.Sc. and M.Sc. in Mech. Eng. from the Technion IIT)
FIRST Volunteer - 2007 - ? (MC, FTA, FIRST Aid etc.)