OK, as stated previously, they must have sourced different components. My KMB-1 (originally a B, not Bx) definitely only has a 3 phase spindle motor but not 3 phase auxiliary fan in it. The motor has an integral fan on the top, but that is mechanical, being driven off the second spindle. Of course, cooling in that fashion isn't adequate for a VFD driven motor, hence the addition of the boxer fan. But as I previously stated, that is a single phase unit that is very generic.

So, clearly there are no blanket statements here without some caveats. That being said, the one thing that can definitely be said is that the control system is single phase and although the spindle may be three phase, it is small enough that most modern VFDs can drive it with a single phase input. If the VFD can't, buying a suitable one that can will not set you back a whole lot of money. So, converting a Hurco to run single phase is fairly trivial in the end, even if you are talking about keeping the original control.