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Unread 23-12-2006, 16:13
dawilliams dawilliams is offline
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Join Date: Dec 2006
Location: Hampton, VA
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Re: motor stall current vs Victor ratings

Thank you all for your replies. This is certainly a credit to the FIRST gracious professionalism creed.

Still one curiousity comparing my BBIQ experience with FIRST robots. Most teams at BBIQ used 24v systems for drive, motors from 1-3 hp PER SIDE (or 2-6 hp total in the differential drive), and batteries with 5-6 AH ratings. The playing surface was sandtextured paint on steel, which ended up fairly slick by the third day of competition. If two bots pushed against each other, one would move or the wheels would spin. This lack of traction compared to rubber on carpet as with FIRST would protect BBIQ bots from burning up Victors or motors. But I still saw several burned motors or Victors (pink/grey smoke) each year.

The FIRST motors are approx 1/2 hp for the largest ones. The battery has higher AH rating letting it keep up with whatever the motor draws. The playing surface with rubber tires is less forgiving (no slipping to protect the Victors and motors). To my thinking, this means robots pushing against each other won't be able to move each other. Thus more likely to stall the motor. Even geared down, if you push against the side of the opponent, you won't be able to move it, and that is still a stalled motor.

The 4 largest motors draw 133, 96 or 63 amps at stall. That exceeds the 40 amp rating of the Victor 884. The Victor 884 doesn't list a higher current for any short time (as the Victor 885 does).

So do you suggest a single Victor 884 for one of these large motors, or two in parallel for each motor, each with an independent 40A circuit breaker?

Thanks again!