I have a similar problem. On my 20hp phase converter, all three legs were 253-254 volts, which was too high to even turn on the machine. (the dealer wouldn't turn on the machine until the voltage was below 240 V)
I checked into our power company's tolerances, and they would allow a pretty wild variation...can't remember, but I think THEIR tolerances allowed up to 260 volts.
Bear with me...I didn't do so well in my EE course in college:
When I asked why our voltage was so high, I was told it was because we were the first building off transformer by the road. They also explained that someone further away may have a slightly lower reading than us, and that they were constantly "tweaking" the voltage due to load on the entire system.
So I've been told, voltage on the high side isn't a bad deal for typical household appliances. More sensitive stuff like televisions, home theater components, and computers all run the AC power through a transformer and really runs off of DC power that is regulated through the power supply, so the AC voltage variation doesn't really affect these. (other than giving the power supply a workout)
As I'm sure you know, in terms of voltage, the phase converter just puts out what it gets in. In our case (and probably yours) it was cheaper to buy some buck boost transformers that knocked down the 3 phase to 230-ish rather than try to tackle the large single phase line going into the phase converter. We bought our transformers from Acme Electric for about $400 (13kVa).
Good luck
Justin  |