Stupid is as stupid does
- Jun 10, 2020
- Member Number
- Durham, NC
15hp is 15hp so it's still going to require the same amperage feed whether it's straight single phase or single to a VFD. I believe the rule of thumb on a single phase VFD is to size the feed wire for 125% of the motor size....so the feed to the 15hp VFD should technically be sized for a 70a circuit.
Amps arent the same when comparing different voltages, say 15hp w/460v vs 15hp w/240v. Also, three phase motors have three conductors to send the amps, meaning less amps per conductor, as compared to a 240v single phase motor.