On Thu, 10 Jun 1999 rtriplett@bjservices.com wrote:
> Are there brushes in an altenator? I'm not trying to be a smart a** here, I
> really don't know, but thought since it's an AC generator they were brushless.
> I've only worked on generators which DO for sure have brushes, but always just
> exchange altenators. The symptoms described above make it sound like a bad
> diode, causing just half-wave rectification, therefore less current available.
Yes, there's brushes in an alternator! However not quite in the same
arrangement as a generator- in a generator (and an electric motor) the
brushes ride on a shared commutator; this is so that the polarity will
switch on the armature and cause the motor to turn, OR so that the
polarity will switch and cause the generator to ...uh... generate.
In an alternator the brushes ride on seperate commutators. The principle
is the same- a magnetized armature being flung around in the magnetic
field of a magnetized stator winding, causing the movement of electrons
(Electricity!!). This electricity has to be let out of the alternator
somehow- so there's 2 brushes in your alternator. In GM alternators the
brushes ride side-by-each down at the endbell of the unit, in Mopar
alternators one rides on the shaft of the armature and one rides on a
circular platter on the rear face of it... and I've never had the joy of
dismantling (or mantling) a Lucas alternator.
-Malcolm
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