Re: Motor calculations? Help!

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Roy J. Tellason"
<rtellason@b...> wrote:

> On Saturday 19 March 2005 08:39 am, Lance Hopper wrote:
> > Hello,
> > I've been talking to the guy myself trying to help him out.

He's

> > already bought 200V 40A Rutex drives as I understand. Now he's
> > trying to figure out the PS.
> >
> > The original drives were fed 120 3ph from the secondaries of a
> > 2.5kva 3ph transformer as he describes via his electrical

schematics.

> > He was trying to see if the stock 3ph transformer (has delta and Y
> > wiring configurations, he has the schematics, maybe he should

post)

> > could take ~220 1ph (all he has available) and output ~120 1ph

that

> > could be rectified and used for the Rutex drives. I doubted that

it

> > would work and be dangerous/stupid to try, but what do I know.
>
> If you wire up a 3ph transformer and each secondary is rectified

and all

> rectifier outputs are fed to a common filter I don't see where the

problem

> is. Not that I'm saying there isn't one, just that I don't see

it. If

> there is can you point it out for me?

You're missing that he only has 120/240v single phase power to feed
the three phase transformer. He should be ok feeding one or two
sections of the transformer with the 120/240v (quasi two phase).

I'd not try to feed the third section if it's a common core type of
transformer. If it's the less common type of thransformer that is
really three seperate single phase transformers mounted in one
enclosure then you could parallel all three without issues.

Pete C.