Re: [CAD_CAM_EDM_DRO] Three Phase Power

jeffalanp wrote:

>Hi All,
> Has anyone ever used a single phase to three phase rotary phase
>converter to power a variable frequency drive VFD(which itself runs a
>three phase motor)? Is it a good/bad idea?
>
>

Far better is to use a slightly larger VFD, and run it directly from the
single phase!
Most manufacturers will now admit that you can run a 5 Hp motor at full
power
indefinitely from a 10 Hp VFD. For home shop use, you generally can
even run
a 5 Hp motor from a 7.5 Hp VFD without much trouble. The VFDs are rated
for some pretty harsh conditions, such as only 208 V 3-phase, and convection
cooling only in a 45 C ambient temperature inside a cabinet. In 30 C
room air,
and with 240 V single phase power, the rectifiers are under less stress,
and everything
else is about the same.

What you propose is workable, but a huge waste of space and energy, not
to mention
making a lot of noise in your shop. It is simply unnecessary. I am
using a 1 Hp
Magnetek VFD to run a 1 Hp Bridgeport mill on single phase, and it has
no problem
at all, although the manufacturer would have a cow. I also use the same
VFD to
run a high speed spindle on 80 V @ 400 Hz. This draws more current from the
VFD, and I put a fan on it when I do this.

Jon