Re: VFD for a 15HP CNC lathe

Scott, take a look at

www.dealerselectric.com

Ask for Harold. They have some large VFDs for good prices. A 30HP
model will cost about $1578.

You will be hard pressed to find any VFDs rated for single phase
input over 5HP. If you want to run a larger VFD rated for 3 phase
input on single phase, you will have to derate it anywhere from 30%
to 50% depending on the VFD. 50% is the safe rule.

A rotary converter has the advantage of allowing you to run multiple
machines from it. However, it doesn't provide the speed control,
motor braking, motor overload, etc. that the VFD does. In your case,
a 15HP VFD with a rotary may be a better choice as I don't think it
will cost any more. A 15HP VFD is about $929 so that gives you over
$600 for the parts needed to build a large rotary converter.

If you decide to build a rotary, I have a new cast iron Delco 20HP
face mount motor, pedestal stand, mag starter, overload relay,
control transformer, run caps, NEMA boxes, distribution blocks, 3
phase load center, mounting brackets, etc. for a large rotary I was
going to build. I didn't get the machine it was intended for, so I
don't have much use for the rotary now (already have another smaller
on in the shop). I would make you a good deal on all the parts. If
you're interested, you can contact me offline at:

pete @ vavaroutsos.com

408-531-1484

Best Regard,

~petev

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "fuddham" <fuddham@a...>
wrote:

> I have a CNC lathe that has a 15 HP spindle motor. What size VFD
> would I need if I only fed the VFD single phase power? Would it be
> better to get a 15 hp VFD and use a rotary phase converter to feed
> the VFD? What size VFD and Rotary converter?
>
> Thanks,
>
> Scott Hamilton