Problems hooking VFD to a 2HP (3phase) motor

[Dan Friedrichs]

I'm trying to hook a VFD to a 2HP, 3-phase motor to add variable speed to a drill press.

I sourced a used 2HP, 1725 rpm, 200V, 7A, 60Hz motor. I took it apart, cleaned it well, replaced the bearings, etc. Measured 2 ohms of resistance phase-to-phase, and no phases shorted to the chassis, so it seems good?

I think this is the "ideal" motor for a drill press 3-phase conversion, since it's low speed and 2HP should be sufficient.

Just for extra overkill, I bought a VFD that supports SVC for extra low-speed torque.


I have the VFD hooked to the motor and operating in V-Hz mode. Motor spins and speed is adjustable, but I'm surprised at the current draw. Each phase is measuring 4.5A with no load on the motor. That seems very high to me? Also, it's making noises - I know the VFD will obviously produce some harmonics, but there is some lower-frequency "grumble", as well.

Additionally, when I try to run the auto-tune procedure for the SVC mode, it trips an over-current error.

Any ideas on where to go with this project?

[Rollie Meyers]

Does the VFD have provisions to adjust the output voltage? 200V motors are intended for 208 volts, not 240V, while that does not answer your questions, it is relevant.

[Dan Friedrichs]

Yes, I've set it to 200V.

[Carroll Courtney]

If it's new vfd the maker or brand should have a support desk that will help out.They will walk you through the setup and little troubleshooting

[Matt Day]

If it's from factory mation they are extremely helpful.

[Mike Henderson]

Regarding the current, remember that when a motor is unloaded, it looks like a big inductor so the current and voltage are way out of phase.

Mike