Some alternators have a stationary field coil excited by
residual magnetism. The one I disected must have been one
of those.

Doug

The rotor is a revolving field with the "cage" or claw producing north and
south magnetic fields. the "Stator" is short for "Stationary armature" and
unlike a DC generator, the field rotates inside the armature instead of the
other way around.
"Alternator" is actually a homade term for "Alternating current generator"
unless there's a make that has slipped by me, all automotive alternators are
actually 3 phase. with diodes cutting out the alternating waves to make a
directional current.

That is the kind I disected too. :-) Very popular on heavy earth moving
equipment for some reason.


the reason is because carbon brushs are prone to damage to from vibration. not
counting getting stuck in their holders by dirt and muddy water. internally,
your typical brushless alternators are also machined better and are more costly
to produce. like everything else in todays economy, the Chinese are pouring it
on the OEM manufacturers and driving prices way down. that is unless you are
talking atou the Niehoffs and Electrodynes. and they are actually small
companies , that is compared to Delco Remy and Prestolite.
and they also manufacture specialty products . so you wont find any price
reductions with those two brands. in fact that 250A12V niehoff is about a
$3000. unit! Leece-neville and powerline have a 200 amp brush alternator that
can be had for less than $700.00 though

That's called a permanent magnet alternator. My KISS
wind generator uses this technique.

Doug, I've experimented with stuff like that , and you can actually take a
typical 12v heatermotor from a late model chevy etc. mount a prop on it and get
power out of it.
not alot, and not effeciently...but interestingly notable

The rotor had opposing
poles same as any rotor, but with the one end open the poles were attached
in the middle with a plastic ring.
Kinda hard to describe!
Greg

you're almost right Greg, that "plastic ring" on the DELCO SI brushless ia
actually a mylar coated aluminum ring that wont disturb the field current in
the poles, but yet cuts dapers the harmonic vibration of the poles so they
don't stress crack , and fly apart. LOL!, I've seen that happen, though..it's
rare, but when it does happen...theres hardly a good bolt left in the unit.

I believe I already clarified my statement a couple of weeks ago.
The unit I dissected way back was a Delco that did not have
brushes. I incorrectly extrapolated that experience. Pay attention.

Doug
s/v Callista

"BSCHNAUTZ" wrote in message
...
Alternators don't have brushes

LOL!

oh yes they do. tht is unless you run something like a 20,25,30,32,29,35
SI
Delco or a Niehoff, or Electrodyne, and a couple other oddball makes

Why do I care about this? How does it relate to the OP's question or
anything I said? I have a couple of PM tape drive motors that put out
quite a bit of power. Very populat among the homebrew wind generator
crowd.

Doug
s/v Callista


"BSCHNAUTZ" wrote in message
...

That's called a permanent magnet alternator. My KISS
wind generator uses this technique.

Doug, I've experimented with stuff like that , and you can actually take a
typical 12v heatermotor from a late model chevy etc. mount a prop on it
and get
power out of it.
not alot, and not effeciently...but interestingly notable

Why do I care about this? How does it relate to the OP's question or
anything I said?

beats me..

Only you can answer those questions

I incorrectly extrapolated that experience. Pay attention.

hard to do from an AOL newsgroup