3 Phase power

S

Thread Starter

Scott

I need 3 phase power to run a CNC lathe.
10/15 HP motor (plus servos) with 28kva requirement on the cabinet.
The machine is about 120 feet from the main panel.
Should I go with a rotary phase converter, or an inverter drive. And if an inverter drive is used do you need a motor with that or just the inverter.
And is there any benefit from a used 3 phase generator (ie is it cost effective to make your own power)
Thanks
 
hello scott
What type of power is currently available to run the lathe? Inverters can make 3 phase from single phase, but only for a single drive.Off hand you should be able to find a converter to make the power you need.
 
> I need 3 phase power to run a CNC lathe.
> 10/15 HP motor (plus servos) with 28kva requirement on the cabinet.
> ...

Is the 3 phase needed for the motor, for the servos or both? Feeding inverter sourced PWM 3 phase power into the front-end of the servo amplifiers is problematic since they themselves are essentially an AC/DC converter as well.

It is entirely possible that if you look carefully at the servo amplifiers they really only need 1 phase input. If so it might be more cost effective to split your system. Supply 1 phase AC to the servo Amplifiers, then feed the 1 phase power into a VFD inverter to control the 3 phase motor. Any VFD will be able to take a 1 phase input and give a 3 phase output, but you will need to double the size of the VFD. For instance, if you have a 15HP motor, buy a 30HP VFD.

A rotary phase converter sized for the entire load will work as well, but if you want variable speed on the spindle drive you will need to buy a VFD for the 3 phase motor anyway.

By the way, there is no such thing as a "transformer" that takes 1 phase in and gives 3 phase out. Something must create that 3rd leg, be it electronically (inverter) or magnetically (rotary). Either choice will be less expensive than generating your own 3 phase power.
 
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