Horse Power

[Sh1ine]

Does anyone know how much HP is created by a CIM?

Currently we have 2 running in a custom transmission with a 7.1:1 reduction.

[2611.Shooter]

340 watts = 0.45594751 hp
(confirm watts?)

[BHS_STopping]

Certainly no more than 480 watts, since the CIMs can theoretically consume 40 Amps (before the breakers trip) over 12 volts, which equates to 480 watts (Power = Current * Voltage). However, due to losses from heat (which is quite substantial, just try to put your hand on a CIM after a match) this number is probably much lower.

[theprgramerdude]

What Shooter said, although I believe the max power is 343 watts at 66 amps. After gearbox losses, It's likely to be closer to 280-310 watts per motor, or .375-.415 HP per motor.

[Sh1ine]

Thanks. One more, how do I find out how much torque is applied after the gear box?

[theprgramerdude]

You'll have to be more specific, as the torque output by the motor will be dependent upon the current being applied to the motor, which is then dependent upon the voltage and spinning speed, which itself is based upon what resistance it encounters and the torques being applied.

[WizenedEE]

Originally Posted by Sh1ine

Thanks. One more, how do I find out how much torque is applied after the gear box?

http://usfirst.org/uploadedFiles/Rob...rves_Rev_A.pdf

Torque is on the bottom, and you'll probably want to look at current. Since you can't apply more than 40 amps, you'll get about 120 oz-in of torque.

[AustinSchuh]

Originally Posted by WizenedEE

Since you can't apply more than 40 amps, you'll get about 120 oz-in of torque.

You are assuming that the breakers will limit the current to 40 amps, or blow instantaneously at 40 amps. That is not true. You can draw much more than 40 amps for short periods of time. It is not a good idea to require more than 40 amps of current for extended periods of time, because eventually the breakers will heat up and blow, and the CIM will start to get rather hot.

[Al Skierkiewicz]

Guys,
40 amp breakers (actually all breakers on the robot) can withstand short periods (seconds) of 600% over rated trip current. CIM motors stall at 133 amps which is well below the 240 amps that would instantly trip the auto resetting circuit breaker. The breaker resets almost instantly.

[D.Allred]

Originally Posted by Sh1ine

Thanks. One more, how do I find out how much torque is applied after the gear box?

I assume you are designing a drive train and need to determine load on the system at that gear ratio. Load depends on several factors. For FRC drive trains, most people use JVN's Advanced Drivetrain Calculator. You can find the spreadsheet and presentation file at the link below.

http://thinktank.wpi.edu/article/5