Rotary Phase Converter (Create 3-phase power from a single phase source)

[Frank S]

My rotary phase converter is kind of small actually too small in some ways,being only a 3 Hp it is started by the use of 3 large capacitors with no small spin up motor. I really need to build a larger one with a spin up motor but it came with my lathe when I bought it and has been running it for a few years even though my lathe is 4 hp, as long as I don't try to make a .200" cut @ .015" feed it does just fine any heavier cut and it will bog down.Also I have found that if I switch on my 3 Hp mill and just allow the motor to run without any work being done then the lathe do a little better when starting it or reversing it.
I an thinking that when I build a larger converter I will use a 1/2 or 3/4 Hp spin up motor direct coupled to a 7.5 or 10 Hp motor with a large flywheel to help with the higher current load my 450 Amp mig welder will require