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[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Doug,

I would avoid a 110 V VFD/spindle.

@Aiph5u

With 120 V you should be aware that all your wires and fuses will need to be dimensionated for double the current as if you use 240 V.

A VFD with single-phase input made for a 2.2 kW spindle draws about 4.8 kVA max. power. With 240 V this means up to 24 A current, fuse got to be 30 A, VFD wire size at its input got to be 5.3 mm² (~AWG10). If you want to use the same input power (kVA) with 120 V, you got to double all these currents and wire cross-section areas.

Also see what Daniel @PwnCNC writes about their 110 V spindle:

Note: The 2.2kw 110v motor requires 20Amps of power. None of our VFD’s are capable of providing this much power¹. Also note that it’s recommended you install a 30amp 110v circuit to supply the proper power for this type of motor. We purchased a small batch of these motors to test/validate but ultimately decided not to offer in a full spindle kit.

1. Daniel means current, not power

Note that I don’t know how Daniel comes to 30 A for the input of the 110 V VFD, I think that’s not enough (best is to see what’s on VFD nameplate – NOT spindle nameplate). I own a 2.2 kW 230 V VFD and it is rated with 24 A input and needs a 30 A fuse. With the same power (2.2 kW spindle power) but at 110 V voltage you need double the current (ampères) which would mean the VFD sufficient to drive such a spindle would require a rated input current of 48 A (and a corresponding fuse).

I think there is a reason why Omron produces no 100 V class VFDs and Hitachi produces 100 V class VFDs just up to 0.75 kW – because current (and subsequently wire size) would be too high, particularly on single-phase input.

Note that in the U.S., many people have split-phase electricity (two 120 V phases shifted by 180°) which means even if they seem to have only 120 V outlets (which is between one hot and neutral) they usually have 240 V in their homes (between two hots of different phases) so an electrician can easily install a circuit with a 240 V outlet and circuit breaker.