Get a 480v vfd, run it from a transformer, and program the vfd for around 300 volts at 60hz. This will give you around half the hp at less than half the no load amps. ( All of which get recycled in the vfd anyways, which only has to supply the motor losses and the load)
Keep the motor in highspeed configuration . Look at the nameplate 26amps at 1750rpm vs 21 at 850 when delivering half the hp.
Two speed motors are also much worse power factor in low speed mode unless the windings are optimized for low speed, in which case the highspeed config would not be double the low hp.