How big of Rotary Phase Converter needed to run 3phase 315lx tig welder on one phase?

[DXN1EL]

Call your electricity provider and see if they can bring 3 phase, I have three phase at home!

[TheGary]

I would not use a rotary phase converter with a welder. If you do you would need a 15 hp rotary converter to do a decent job with it. Rotorys do not make very good power. I have a Phaseperfect digital converter and it will run any kind of 3 phase load but they are costly. I have a hydra shift lathe with a 7.5 hp motor and I would have needed a 15hp rotary converter to run it well. A 10hp minimum but there would have been limitations with it. I believe the smallest Phase perfect is 10 hp and it is about $3000. To me any welder under 300 amps there is no need for 3 phase. Even most industrial welders run 440 single phase. A rotary converter will about double your electrical usage for a given load. A phase perfect is 97-99% efficient and continually corrects for unity power.