Motor Resisting Variable Downward Force

[omalleyt]

I have a system where a cable is pulled down with a load of 100-200 lb. I need a motor that resists this load with a force that can be programmed to be anywhere from 5-30 pounds. I don't want the motor to stop the downward motion, just to offset the magnitude of the force pulling down on the cable. I will be using an Arduino to control the level of resistance provided by the motor. Is this possible and if so what type of motor/system could I use? Thanks!

 

[sophiecentaur]

Any electric motor can work 'in reverse' to produce a braking effect. The only problem would be that it would have to cope with what really is a sustained stall current - or worse - so you could need a beefier motor than you would use conventionally. Just by shorting the supply leads to an unpowered motor, you can produce braking (you've got a generator, in effect, which takes energy). I recommend googling regenerative braking and see what you get. This is quite a hot topic at the moment so you should be quite lucky there.

 

[jim hardy]

try a google on "torque motor"

it might do what you want I'm not sure