On 13 Sep 2004 18:19:17 GMT, (Charles A. Sherwood) wrote:
All this talk got me to reading my audels electric motor book.
They state that a synchronous motor is almost identical to
an alternator. Since I have a 3 PH alternator, I was wondering
how hard it would be to make it run as a sync motor and once
it is running to use it as a rotary phase converter. This would
be more efficient than driving it with a single phase motor.

My limited research seems to indicate that I need to get it
very close to sync speed with a pony motor and then apply
power to two phases and DC to the field. Then it should
motor just like a motor and hopefully the third leg will be
generating. Yes or NO?

Should work, but there won't be any automatic voltage regulation
of the phantom leg with varying load (slip does that for you in an
ordinary squirrel cage RPC). You'll need to dynamically vary the
field current to regulate the 3rd leg voltage with changing
loads. Alternator regulators normally do this, but configuring one
to only look at the 3rd leg voltage might cause a bit of head
scratching.

Gary