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Unread 30-03-2010, 22:55
Jimmy Cao Jimmy Cao is offline
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Re: 30a breaker for 40a spot on pdb

Popping the 130A main breaker shouldn't be a big worry. Can it be done using standard KoP components in a safe and legal way? Of course. Is it easy? Nope.

I believe the 130A breaker is thermal based. Last year, we managed to trip it during practice, after running for ~1.5-2 hours stopping only to do battery changes. Our robot last year utilized just about every KoP motor, short of 1 globe and the window. At peak current, it was probably getting close to 250A. On average, I would guess it was approximately 100A (due to the nice slippery floor surface).

My point is, during a 2 minute match, it would be near impossible to pop the main breaker without an electrical fault. If I were you, I would just run the motors through 40A breakers. I suspect that even stalling the motors for 2 minutes wouldn't trip the main breaker, although it would begin tripping the 40A ones pretty quick. Sustained 200-250A for 2 minutes through the main breaker might be enough, but I don't see how you can possibly sustain such a high current draw for a full match. I'd be more worried for the batteries at that point...
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