[Don Lester]

I have a Dayton #3hx73 VFD, which is a IGBT torque vector PWM control. It is rated at 2hp, 3ph-230v output. It's INPUT is rated at 230v, 3ph. Can I wire this unit to 220v 1ph to power my 1hp 3ph Bridgeport spindle motor ? If yes, which input leg do you omit ? Thanks

[Al_The_Man]

Most current VFD's under 5hp will run on single phase, you should make sure from the manual or manufacturer first that this particular model will, the ones that don't are getting rare.
If you already have the VFD, hook it up and try it on 1ph, it should let you know if it doesn't like it.
Normally the inputs are labeled like R-S-T for the 3ph in. Typically you would use R-S for the 1ph.
Al.

[Don Lester]

Thanks AL, you really are the MAN. My unit seems to work OK on 1ph input, however it does lose some power when you really slow it down, is that normal ? I've read else where that DC is really the best way to go.

[Al_The_Man]

There are VFD's that now operate in Crane and Elevator duty where high torque is still available down to zero speed, I have seen a crane hoist hold a load stationary!.
You pay a bit extra to get this quality.
A DC motor drive will also provide maximum torque at zero speed, but generally these cost way more than a comparable high quality VFD.
Al.