I'm getting a ton of conflicting info on what size phase convertor I will need. The machine is a Mazak 250 MSY and is 56 KVA. If anyone is successfully running one on a convertor, what HP size is required? I've got
56 kva at 230vac works out to ~243.478 amps.
HTH
Umm, 240 V x 200 A is 48 KVA. Sounds like you have a problem. Gee, a 56 KVA phase converter is going to draw a HUGE amount of lagging VARS, even before you turn on the Mazak. This can be compensated to some extent with a capacitor bank. This sounds like the kind of machine that REALLY wants to run off 480 and REAL 3-phase. To work right, you'd need something like a 150 Hp motor in the converter. The starting surge of that motor on single phase would likely be in the 1000A range. You can possibly reduce that with a soft-start circuit, but the idling current is still going to be very high. Doing a little net research, it appears to have a 30 Hp/30 min rating on the spindle, so I think the 56 KVA might be a bit high. Maybe that includes the starting surge of the spindle VFD.
Jon
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