I have a Jet 1642-2 which is a 2 hp 220 v input lathe. It has a 3 phase motor on it with a VFD. You can turn the speed way down to almost nothing, though you want enough speed to effective turn your item. I normally don't turn under about 300 rpm's minimum while knocking the edges off 'big' stuff or just checking balance on something. Thing is, you want to try turning at too low an rpm as I don't think it's good for the motor.