Thanks for the fast reply, Tony. My 2HP, 3ph lathe came with a new (at the time) RotoPhase converter and 5 HP motor. The lathe also has an antiquated mechanical, infinitely variable drive. Everything has been in storage for the past 30 years and not used. However, my understanding is that the old phase converters were quite noisy. Since I need to convert the lathe to single phase it would be nice to simplify the variable RPM drive. I was considering a VFD because it may be quieter and more efficient than the RotoPhase but also because it would simplify RPM changes. Your thoughts . . .