[Ken Leung]

[quote=Joe P]I was considering using the CIM as a winch motor for the pull-up bar.

If our 130 lb. robot was directly under the bar and was pulling up from the center of mass, say 12 inches off the ground it would take a maximum torque of 130 lb*12 in = 1560 in-lb.
QUOTE]

This is only true if you have a 12" lever arm at the shaft of the CIM motor. 12" off the ground isn't the right number, because no matter of far you are off the ground, the amount of torque you need to lift the robot remains the same if the speed of going upward remains the same.

It takes 130 lbs to lift up a robot. The stall torque is 20 in-lbs. If you have a winch, and the diameter of the winch is 5 inch, your motor can excert 4 lbs upward force at stall torque. 50% of that is 2 lbs upward force. 130 lbs / 2 lbs is 65:1 a reduction ratio. You should note that this is moving at 50% free speed, so you should check and see if this is too fast or not.