Quote:
Originally posted by rbayer
We could easily stall the motors by putting our robot against a wall and we occasionally managed to do it while turning.
My guess is that our treads finally got worn down enough to the point where they would start slipping before we reached stall torque.
Side note #2: does anyone have any data on how much current it takes to trip the 120?
--Rob
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Rob,
I agree that the motor stall is a serious issue, both the drill motors and the chalupa's have over 100 amp stall current ratings. Four motors in stall is 400+ amps.
Worn treads likely helped in turning where significant side loads cause current to skyrocket. At least one team at GLR had an adjustable center bogey wheel that helped in their turning. I asked them about current draw and they replied that the adjustment made a significant improvement but it was still much higher than in forward motion.
The 120 amp breaker specs are not nearly as good as last year. (documentation that is.) The breaker can handle short over currents of up to 300+ amps. As the breaker sustains each of these high current conditions, the trip point degrades a little. The internal temperature of the breaker has a lot to do with this and eventually if the breaker has reached a critical temperature, it will trip off with less than 120 amps. If you are drawing 200 amps or more, I would plan that the breaker can only handle that for about 15 seconds before it trips off. At that point you better change strategies and run straight or stop to let the breaker cool down.