Convert 1 Phase 1 HP Motor to Variable Speed ?

Mike Turner

Member
Messages
361
Location
Laurinburg NC
Is there anyway to convert a 1 phase 1 HP motor to variable speed without 3phase without step pulleys ? I want to do away with the Reeves drive on my Jet 1442VS lathe also.
 
You can do it with a PWM - which varies the frequency of the 60hz power from the city. You'll likely find that they cost more than a new DC motor and controller, usually, though.

This question comes up quite often and sadly the short answer, like Don said, is no. Induction motors rely on the frequency of the AC power coming in to set their speed. Dimmer switches and router speed controllers don't vary the frequency, just the voltage. With induction motors, a drop in voltage means it will pull more amps which leads to more heat or blown circuits or worse - a smoking motor. Routers and other "universal' motors actually rely on the voltage to set their speed - most of them actually run just fine on DC current, too - which can't be said for induction motors.
 
You can get single phase input/single phase output drives, but they have to be used with permanent split capacitor motors (or shaded pole single phase motors.). I 'm not sure what a shaded pole motor is, but when i had a day job had a few applications that permanent split capacitor motors with a drive. Regardless, it can't be done with your existing motor and changing it out would be best done with a 3 phase motor and a cheaper VFD. It would probably cost more than the lathe.
 
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