On Monday, October 19, 2015 at 7:07:47 PM UTC-4, wrote:
I need to control the speed of a 1/3HP 120V AC motor. This motor/speed control would go onto a wood lathe and replace the pulley system which is now in place. Does anyone know of a solid state speed controller that I could perhaps build to to this? Thanks, Lenny

I think that this motor came out of a sump pump of the type that stands on the top of a sort of 3 foot pedestal. The pedestal would then go down into a hole such as the basement floor. Float switches would turn it on to keep the cellar from filling up with water.

This motor has no brushes and I'm fairly certain that it has a start winding because you can hear the centrifugal switch engage and disengage during start up and slow down. I do not have the exact speed information at hand however I do know that this motor runs at around 3000RPM. There is also very large capacitor on it as well.

So from what I'm reading here is there no real practical way to control the speed of this type of motor other than (as Mr. Cook mentioned) using a stepped pulley arrangement? Lenny