Re: [CAD_CAM_EDM_DRO] VFD's

Tim Goldstein wrote:

>Check the specs. Many of the VFDs require you to derate them by 50% when run
>on single phase so that for a 3 hp application you would need a 6 hp or more
>VFD. I have never seen a 6 hp so you would go to a 7.5 hp.
>
>

Running a 1.5 Hp motor on a 7.5 Hp drive may cause problems. The VFDs
are tuned for the motor
inductance, and a 7.5 Hp motor has a vastly lower inductance than a 1.5
Hp. This can cause problems
with the PWM schemes they use to approximate the sine wave. Also, the
current limits may not go
low enough to protect a 1.5 Hp motor.

Jon