110v or 220v?

[Aaron_W]

Ok, 20 amp 220v it is!

Something to think about, 240v up to 20A you can run a duplex outlet which can be nice if you have another small 240v machine.

However if you plan on running a VFD you may need a 30A or better circuit, so if that is something you may do it is worth planning ahead before running wire.

I have a 1hp VFD on my 3/4hp mill, and it required a 30A even though the motor alone would have been fine at half that.

 

[rwdenney]

Something to think about, 240v up to 20A you can run a duplex outlet which can be nice if you have another small 240v machine.

However if you plan on running a VFD you may need a 30A or better circuit, so if that is something you may do it is worth planning ahead before running wire.

I have a 1hp VFD on my 3/4hp mill, and it required a 30A even though the motor alone would have been fine at half that.

This surprises me. As I said earlier, my (nominal) 5HP rotary phase converter only needs a 20A circuit running single-phase 240, per American Rotary, with up to 50 feet of 12-gauge cord for my floor model. That's what I'm using at it starts up with enthusiasm, though I've not yet used it under load. It's rated to run a 2.5HP motor that starts unloaded (and, of course, the RPC should be started before the load motor), at 240V three-phase, also using 12-gauge wire. The full-load amperage of the Bridgeport 2HP motor it's going to run is 5.5 amps for each of three phases, which should draw 8.2 amps from a 240V single-phase input. The RPC draws much more than that due to its own inefficiency, but it's still way under the current limit for 12-gauge wire (20 amps of branch protection but 30 amps of maximum ampacity). I had always thought a VFD was a bit more efficient than an RPC, just based on the size of parts, but apparently not.

Rick "lots of big capacitors, I suppose, sucking up inrush" Denney