i want to slow down a 12 V DC actuator with a variable resistor to increase torque.Does anyone know of any resistor for this purpose ?how do i wire it to operate back and forth smoothly?
I am thinking of using progressive Automation linear actuator with the following specs:Linear Actuator (Stroke Size 9", Force 400 Lbs, Speed 0.59"/sec) .Does anyone know of any other brands which can be slowed very easily to increase using a variable resistor to increase torque.

 

A resistor will decrase speed as well as torque. You would have to use PWM with higher voltage than it is originally rated, but that could result in frying the motor.

The only way to reliably increase torque and reduce speed is gearing.

 

what type gear would you recommend to reduce speed much considerably?

 

So if i should reduce the voltage by 50%,the torque is also going to be reduced by 50% right?

 

So if i should reduce the voltage by 50%,the torque is also going to be reduced by 50% right?

It's not linear. The torque will be decreased by well over 50%, and a 50% decrease in voltage with the motor under load will probably fry it.

 

Torque is a function of current, not voltage.

 

What exactly are you trying to do?
How much weight are you trying to move?
You mention increasing the power on a 400 lb actuator, what are you trying to accomplish?

 

Have you considered reducing the speed and increasing the force via a lever?

pilko