Re: [CAD_CAM_EDM_DRO] Re: CNC on home built phase converter

paul@... wrote:

> >
> > Scott,
> >
> > I know of two shops that are running multiple large CNC's from home
> > made converters.
> >
> > I run a 5hp mill and a 5hp lathe from converters I put together.
> >
> > A few things you may want to be careful with.....Make sure the
> > controller isn't fed by the "wild" leg. There may be some issues if
> > the spindle motor is driven by a VFD, I've heard mixed reviews on
> > running VFD's from generated 3 phase.

If the machine only has one 3-phase motor, you can run the VFD on
single phase, and run the motor from the VFD. This avoids the
need for the converter completely. You can either make the choice
to not load the VFD (and motor) to full capacity, or get a VFD with
30 - 50% greater capacity than the motor to compensate for the
single phase input. I've been doing this for over 2 years now with
excellent results.

If the machine has coolant, lube or other pumps and motors, then you
may need the rotary converter to power them. But, you could live
with a much smaller rotary converter for those loads, or use a separate
VFD set to 60 Hz for them. The VFDs are much more efficient,
as well as quieter and smaller than the rotary converters.

Jon