Rheostat on capacitor motor?

[williamsmithaud]

I have an old Dayton 1/3 HP 1725 RPM capacitor start 120V motor that I am trying to put into use as a bench grinder/buffer.

I would like to be able to control the speed of the motor through use of a rheostat without significant loss of power.

I had thought about using a ceiling fan speed control, but I don't think those motors are usually capacitor start

Can any of you motor experts out there tell me if this is possible; and if so, what kind of rheostat (or other device) I should use?

BTW, thanks to those who helped me with the starting problem on this motor. It was a loose capacitor connection.

 

[electricman2]

Re: Rheostat on capacitor motor?

Sorry to disappoint you but I don't think the speed of split phase or capacitor start motors can be changed because the centrifugal switch will close at about 75 or 80 percent of full speed and energize the start winding.

 

[Guest]

Re: Rheostat on capacitor motor?

Electric man is correct. Capacitor start and split phase motors have centrifugal starting switches which close at roughly 75% of speed to take the motor off the start winding an onto the run winding. Also most grinder motors are 3450 rpm not 1725. A 1725 rpm motor would not work well for grinding purposes. Why do you want to control speed anyway?Oh well good luck!!! Joe.