View Full Version : VFD With Transformer??

06-04-2008, 12:58 PM
Bought a machine that the motor is wired for 550volt 3 phase. It comes with a transformer that is 220 3 phase.

I am putting it into my garage and need to convert from single phase to 3 phase. Will a vfd wired before the transformer work?


Mike Nash
06-04-2008, 06:09 PM
Probably not, at least not for long. In the old days ( ;) Pre-PWM 1980's) a VVI (Variable Voltage Inverter, six step waveform) could do it, though we usually used a 50 Hz transformer between the drive and motor. The efforts I've seen more recently by Yaskawa and Allen-Bradley involve output filters before the transformer and neither were greatly successful due to filter failures. These were 4160V motors at 500HP. The old VVI's they replaced worked fine. You would be better off replacing the motor with one that can be wired for 230V.