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Transformer

Scattered Parts

Mike
Premium Member
So I am almost ready to start up the Emco Maximat 13. Just one small problem. It runs on 440 volt 3 phase. The motor cannot be rewired to a lower voltage.

I have a 15 hp rotary phase converter in my shop that powers the shaper and mill. It is 240 volt.

I am not interested in a VFD for the lathe. Since I already have 3 phase power I was thinking that a step up transformer would be appropriate. According to my calculations I would need 3.7 kVA from the transformer just to run the motor. Including a safety factor of 2 for motor starting leaves me with a minimum requirement of 7.4 kVA. Most 240 to 440 step up transformers i have seen online are around 9 to 15kVA at the small end.

The question I have is twofold. First where does one find such a transformer and secondly would a 240 to 480 volt transformer work in this situation if one in 440 volts is difficult to source?
 
I have seen some 3PH transformers on kijiji, but you can check motor places that do maintenance - sometimes they acquire used ones, or know where a client might be getting rid of one...

any 3PH 2X transformer will work just fine.

Have you considered changing the motor? it might be a lot cheaper than a transformer. Some of the guys here have 'extra' 3PH motors...
 
I considered changing the motor, but since it is a two speed motor, there is a considerable amount of electronics tht would also need to be changed. Also I would lose the brake on the motor.

The electricsl system on the Emco is somewhat complicated and there is quite a bit that would need to be changed. The costs of this would exceed a transformer.

The simplicity of a transformer appeals to me. Turn on RPC, flip switch on the transformer and start the lathe. Seems logical to me but if there is a better way, I would like to know.
 
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