Building a Rotary Phase Convertor

[dubliner]

I'm toying with the idea of building an RPC to feed a 15hp 3p blower. Can somone familiar with RPC's answer a few ?'s for me. Firstly, does the Generator motor have to have the same RPM as the demand motor or does that matter, Does it have to be 230v capable as the pump is 230V. The information I find is contradictory so I'd like to talk to someone who does know. My plan is to buils a Cap starter to start the generator and then feed the demand motor. I read that 15 hp is sufficient, then I read that I need 30 hp for the RPC, so which is it? All input greatlly appreciated - PS Love the new forum SB

[kra]

I built one several years ago and still use it regularly to run several pieces of equipment
Mine was 5 hp idle motor 220v 3 phase to run several 5 hp 220v 3 phase motors. Ideally I should have used 7.5 hp idle motor but it works fine with no noticeable loss of power
You will need to balance the 3rd leg coming off idle motor to your other power source for best performance

the rpm shouldn't matter since you are just using it like a generator for the 3rd leg of power

Randy