Thread: Chiaphua HP?
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Unread 11-01-2004, 12:10
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1/2 stall torque X 1/2 free speed only happens at ideal situation

Quote:
Originally Posted by Joe P
The Formula for any motor is Motor Power = 1/2 Free Speed X 1/2 Stall Torque
CIM Free Speed @ 5000
Stal Torque @ 2.2 N*m
The CIM motor would be 5000RPM/2 * 2.2 N*m/2 * 2 *PI/60 = 317 Watts
Please note that this is the MAXIMUM amount of power your motor can output at the most ideal situation. If you gear your motor to move exactly at 50% of the free speed and output exactly 50% of stall torque, then you will output this amount of power at 12v.

Considering this is a CIM motor with a speed controller, as you are pushing on your joystick or whatever you are using to control your robot component, you will start out at 0v, then 2v, 4v, 6v, until 12v at a curve designed by your programmer. You want to watch out how much electricity you are giving the motor.

As soon as the load on your robot component increase, you will using more than 50% of the stall torque, and the amount of power output will change. Chances are, with all the robots out there trying to get control of big balls, pulling up the hanging bar, going up the steps, moving the goals, you may experiencing more force than you think you would.

So, gear your motor conservatively, and put whatever you can to help your device along so your motor stay as healthy as possible. Understand that at different combination of speed and torque, your power output will be different. Check the speed-torque curve. Be prepared to do a lot of testing to get the right configuration.
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