(05-26-2017, 03:27 PM)Rupert Lucius Wrote: Impossible to control the speed of the AC single phase motor (lowering the voltage - will soon ruin the motor).
Go with a 220V 3 phase motor, between the 120 V wall outlet you will add a frequency controller that steps the Voltage up to the 220V required also controls the frequency to the motor, that manages motors RPMs.
Three (3) phase motor should be inverter duty rated. Not at all necessary - insurance to prevent problems.
Rupert
Mr. Ruppert is correct!
It is difficult to change the speed of single-phase motors. The reason is, that those motors often use a capacitor to start/run the motors. Electrical properties of a capacitor depends on current frequency. The usage of Variable Frequency Driver’s will result in lowering the current in the start winding, which will cause that the motor will not start and will run irregularly.
As far as I know the VDF invertors are used mainly in fans and pumps.
Jan