In article ,
Old Nick wrote:
On 25 Aug 2004 13:18:31 -0700, jim rozen
vaguely proposed a theory
......and in reply I say!:

remove ns from my header address to reply via email

I did some reading. I remember now what my reservation was. While you
can throw plenty into the RPC, they are not good at allowing the
driven motor to produce full power.

This is a problem with a "static" phase converter, but for a
reasonably sized rotary converter -- especially one which has been
tuned and balanced by tweaking capacitance on the windings -- you should
be able to get full power out of the driven motor.

I am wondering what happens to
welders etc. Welding is one area where I see real bargains for very
powerful MIGs etc. I have seen a MIG that gets 350A from 240 volt, but
it was a new model, brand new with a VERy "new" price!

No experience with this, but I can't see any serious reason to
expect problems running it from a RPC. Here, I am not sure what will
happen from a VFD -- given that you have a switching regulator
synthesizing the output of the VFD, and possibly another one converting
the input to the welder into DC, so they might interfere with each
other. (I would also expect similar problems running a typical computer
from a VFD, too.)

But welders (and computers) don't need the variable frequency,
so I see little reason for using a VFD for this.

Enjoy,
DoN.
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