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CNC on Phase Converter3/12
I'm looking into putting a Biesse on a phase converter at a shop with only single phase. I know the control needs to stay off the manufactured leg. Anyone have any experience in this?
We run a phase convertor on our thermwood. Just a heads up make sure the converter is digital as opposed to a rotary converter. It was a $5000.00 lesson we learned the hard way.
What was the lesson?
Most machines (not all) only need the 3 phase power to run the spindle and vacuum pumps. the controller usually can be run off of single phase. The VFD (inverter) will take single phase power and output 3 Phase power to the spindle but at a reduced power level. A larger capacity VFD / inverter can compensate for the power loss.
Rotary converters are okayish for motors, but really, you should not use them on electronics.
I wouldn't mess around with this. Just get a phase perfect and never worry about it.
If you mean they output less three phase amps, that's just how AC works, it will output single phase amps / √3
The reason for larger inverter is not power loss.
It's because if you operate a 3 phase VFD on single phase, you need to derate the available output (due to DC bus ripple, heat, etc)
This increases the size of a needed VFD if you use single phase input.
Rule of thumb is that if you want to use a 3 phase VFD on single phase input, to use one with double the HP rating you need.
Sorry for the late response but with the rotary converter the volt fluctuate up and down run 408 volts and when we checked the 3 legs they would vary from 320 volts to 440 volts. With the digital all 3 legs are the same voltage 412 volts. We went through 2 Siemans power units at $2200 apiece plus tech to install them.