[Hirudin]

Can a derated 5hp VFD run a 5hp motor? In other words, if the OP bought a "5hp" 3-phase VFD and hooked it up to single-phase power, could they assume they would get roughly 2.8hp out of the 5hp motor? If the OP is only looking for a little more power, that 2.8hp might be about perfect.

Plus, I imagine they could run a 5hp motor at 2.8hp for longer periods without worry of overheating it.

[tmarks11]

Can a derated 5hp VFD run a 5hp motor? In other words, if the OP bought a "5hp" 3-phase VFD and hooked it up to single-phase power, could they assume they would get roughly 2.8hp out of the 5hp motor? If the OP is only looking for a little more power, that 2.8hp might be about perfect.

That is another way to go, hadn't thought of it that way.

You could, but you need to make sure you set the FLA (Full Load Amps) setting to be 1/1.73 of the normal max limit of the VFD.

But take that thought one step further: just run your 5 HP motor on a 3 HP VFD with single phase input and save a little money, as it would essentially be the same thing. Over current limiter in the VFD should keep you within the capability of the VFD. Just make sure that you verify FLA (Full Load Amps) is set in the VFD appropriately for the VFD capability (it should be by default), and then set the ramp up speed longer to limit the start-up surge of the motor.

Of course, if you really think you need 5 hp....

I guess if later on you feel you need more power, you can swap your 3 HP VFD over to your lathe, and pay the extra bucks to get a 10hp 3 phase VFD....