Thread: alternators

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have a question about 3 wire and 1 wire alternators.
can you tell them apart by just looking at them not hooked up to the car of course.

can you take a 3 wire and convert it to a 1 wire


thanks for your time

You are going to get a lot of opinions on this subject on both sides of the fence. I have even seen articles that say "Why one wire alternators can't work." We only have one wire alternators on our 3 hot rods, and the one on my 27 has been on there for years. For something that "can't work" it sure has kept our batteries charged and does so even with an electric fan and headlights running.

Don

I've read articles that say a 3 wire is better. A one wire is an easier hookup. Alos you have lots of car guys using both and having no problems. I personally had a 3 wire on my pro street car for 9 yrs with never a problem.
It's basically whatever you decide you want or already have.
The 3 wire has 2 tabs sticking up on the top left of the alternator as I remember.

Originally Posted by 36chevymaster

have a question about 3 wire and 1 wire alternators.
can you tell them apart by just looking at them not hooked up to the car of course.

can you take a 3 wire and convert it to a 1 wire


thanks for your time

Here's a link to a paper that explains how to use either alternator for your vehicle, whether it's hooked up for one wire or three wire operation. Main difference seems to be a warning light?
http://www.oldengine.org/unfaq/10si.htm

Used to have one wire alternators made by local rebuilder and sell them in our auto parts store for many applications including custom hot rods. We even put one in a 1967 Jeep P/U that we put a 427 Chevy into in 1980. No issues with alternator warning lights, at least back then. These were GM alternators. Common rebuilt part # then was the 7127's. In these type of GM alternators they have an integral regulator that is on the side and rear of the alternator. A slot where the regulator sets inside with two male spades. The two male spades in this regulator that would normally be where the plug on the wireing harness would plug into it. On the one wire set up the regulator will be visible from the same location, recessed inside, but will have no male spades. Only location to attach wire will be on back of alternator. I memory serves me correctly when engine RPM's dropped below 500 RPM or close to it, alt. would not charge. Usually hooked the one wire directly to battery.