On Sep 10, 2009, at 7:20 AM, Stephen A. Lawrence wrote:
A generator which powers its own field windings won't self start,
right? You can spin it until you're blue in the face but nothing
will
happen, unless you apply some external power to it to energize the
field
windings and get it going. Once it's going you can take away your
external power source, of course. (Of course if there's "residual
magnetism" stuck in the iron core of the field windings, that may be
enough to get it going -- but a brand new one, right out of the box,
won't self start the first time it's used.)
This may be the same deal. You spin a bearing, and nothing happens.
Well, maybe if you apply external mechanical power /and/ you run a
current through it to get it started, it will start generating
electricity on its own.
But it is not the same deal. If you apply power it works as a motor,
no matter which way it spins, or even if you apply AC.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
