I had a perhaps dangerous thought.
Many 3-phase motors are wound for 220/440 volt 3-phase, with coils in parallel for 220 and in series for 440 operation. It seems to me that if such a motor can be wired in the Wye configuration, one could feed
220 single phase to the center tap of one of the three 440-volt inputs, and take 440-volt three phase off the three 440-volt "inputs". Actually, delta could work as well, so long as one can access a center-tapped coil.The big disadvantage that comes to mind is that that one coil (half of a
440-volt input, so one of six coils) has to handle the entire power input, but then again large used 3-phase motors are not that expensive for their capacity, and one avoids the need for a big 220 to 440 transformer.Joe Gwinn