Circuit Breakers

[Teammax]

I follow what you are both saying and I agree that the CIMs are 40amps. But is there a clear cut rule written down that matches motors to the appropriate ckt bkr? Is every team just going by past experience?

How would you go by wire size? Do we know what size wire is required for each motor?

[Tristan Lall]

Originally Posted by Teammax

I follow what you are both saying and I agree that the CIMs are 40amps. But is there a clear cut rule written down that matches motors to the appropriate ckt bkr? Is every team just going by past experience?

How would you go by wire size? Do we know what size wire is required for each motor?

Years ago, the rules required certain breakers for different motors. Nowadays, FIRST considers the function of the circuit breaker to be protection of the wiring. Teams supply excessive current to the motors at their own risk. Therefore, for general robot wiring, circuit breakers correspond to wire gauges only.

To protect the motor, which is optional, you've got to figure out how much current the motor can draw, and for how long, before failure. The motor's specification sheet is a good starting point for this, because it will tell you what the maximum (stall) current of a motor is. The actual time to failure is not specified—so make an educated guess. Then, you consult the circuit breaker's specification sheet, and determine if it will trip before the motor fails.

[Teammax]

If this is the official stand then it makes sense. We are planning on using a 20amp breaker with 18gauge wire for the RS545 motor but I did not want to fail inspection because of this. I do think both are adequate.

Thanks for your help