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Original alternator for a 1968 442

If it has brushes (not a commutator) then it’s a generator, not an alternator.

I’ve never taken either type apart, generator vs alternator, but I think an alternator has brushes too. It’s just that a generator has alternating segments that the brushes connect with on the commutator, while an alternator uses sort of like a slip ring arrangement to get power to the rotating part; i.e. carbon brushes make electrical contact with a non-segmented ring on an alternator.

Alternators have brushes too. The difference is they ride on two slip rings whereas in a generator they ride on a commutator.

On the early GM alternators the regulators were separate from the alternators.

Any help identifying a good quality regulator would also be appreciated.
The one from the local parts store looked like cheap crap from a foreign country.

Many ubran areas have automotive electric rebuild specialty shops where all the work is done on site. The one near us that I’ve used for years is .
The quality is much better than what many local parts stores provide.

Find one in your area. Or even call the one above to see if you can ship your alternator to them to repair.


Thank you for this advice. If I can find a shop like this one, I’ll be sure to connect with them.

If anyone cares more about this topic, this alternator certainly seems to have brushes. They are small, black (graphite, I believe) units about 1cm x 1/2 cm x 1/4 cm in dimension. They make contact with what I believe are called the slip rings, copper cylinders that are an integral part of the shaft that spins via the pulley assembly.

The slip rings were a bit corroded, so I cleaned them up, first with steel wool (until I discovered all of the little will pieces sticking to the magnets) and then with fine sandpaper. I blew out the unit with compressed air before re-assembly.

I did purchase an original shop manual on CD. Now that will not teach me everything, but certainly a lot (one cannot become a master only by reading, in my experience). Hands-on work is essential but I don’t have a mentor easily available (my father lives on the other side of the country now, but he taught me a lot in my younger days).

Thanks again for all of the advice, and I apologize for misspeaking originally and saying that I cleaned the brushes in the regulator. Having 2 young kids makes for less time than desired to do much other than chasing them around and keeping them out of trouble and harms way.

Best wishes for a great 2016.


Tester: Both of my 1963 Galaxies had generators. Was yours a 1963-1/2? Perhaps that is when they switched?

Main difference between a generator (on older cars) and alternator: they are both AC generators and the difference is how they convert that to DC. In the generator, the power is generated in the rotor (the rotating part) and converted to DC via brushes and a commutator, which is a slotted set of contacts which the brushes connect to as the rotor rotates.

In the alternator, the AC is generated in the stator and rectified by high power diodes. The rotor provides the excitation current, and power is supplied to it by brushes and a pair of slip rings. The slip rings are a continuous contact, no slots, and carry a lower current.