I have a 1990 Mori Seiki AL2 lathe, which I have an american rotary phase converter system to create 3 phase power.
Because the machine expects 600volts, I need to run my 240 3phase created power into a transformer in order to step up the voltage.
The machine has a small internal transformer for the controls to step the voltage back down, and I believe the motors run at the supply voltage, but I'm not entirely sure. There seems to be only one small transformer inside the machine, which appears to be an isolation delta transformer as there are 3 coils there, and not one which would indicate an auto transformer.
So... the main question is do I use an Auto or Isolation 15KVA transformer for the machine. Do I need the "protection" of the auto transformer, or is it not really beneficial since I am running on generated power anyways and the controls already have another transformer internally?
My understanding is that isolation transformers are not quite as efficient as auto transformers, which is of concern to me because I am run at the edge of available amps to run the machine before tripping the breaker.
Auto transformers are 1/3 smaller and more affordable, but isolation transformers protect from voltage spikes, etc.... however since I am on residential power anyways is that even a concern to me?
My thought is that the control is already protected by the internal isolation transformer on the control side, so I should be fine with an auto transformer either way.
Thanks for your help!