I have a wiring dilema. I thought my vette had an externally regulated alternator... Boy was I wrong needless to say during my new engine break-in I heard somethin hissing and began to smell something smoking, it was my new $150 optima battery. Guess what (everybody knows this and now I do too) my vette has an internally regulated alternator. Or in my case no regulator. Oh by the way this is how I came to the conclusion of buying a externally regulated alternator: I thought the horn relay looked like a regulator... It does a terriable job at regulating.

So this brings me to my question, the only shiny alternators at summit are the one wire type. How do I wire it? Someone please answer before I wire it up to the fiber optics or some even stupider.

PS anyone want a slightly used externally regulated alternator?

 

Your better off with a 3 wire internal reg alternator. BUT, if your determined;
http://www.madelectrical.com/
these guys have the skinny on alternators

 

I have just gone through something similar to this with my car. I have done some research on this and this is what I have come up with, when they speak of internally and externally regulated they are speaking of were the voltage is being measured at. If it is being measured at the alternator it is an internal regulated alternator if it is being measured at the horn relay or some were else it is externally regulated. From what I understand if it has one wire hook up it is internally regulated if it has a three-wire hookup it is an external regulated alternator. The voltage regulator is mounted internal of the alternator on both if it is a GM product. I am no expert on this by no means; this is what I’ve come up with after all I’ve read. Someone with more knowledge will chime in and guide us in the right direction.

Neal

 

Older alternators from the 60s were indeed externally regulated with a separate, firewall-mounted regulator box - like a vehicle with a generator.

 

Neal,

That is what I thought too, however, much to my dismay, alternators with 4 wires are internally regulated.

With key on the on position engine not running:

1)power big red one
2) 12 volt
3)4 volt or so, I think the gauge
4) ground, this one is easy attached right to the case.

Don't confuse the external / internal by the number of wires unless you want to fry an egg on your battery.

 

An internal regulated one is just that...it has the regulator built inside. You can tell it because the plug for the two wires into it are in a flat rectangular connector that goes into the side of case.

The external regulated ones have the regulator mounted over on the fender or radiator support usually. It's about twice the size of the horn relay. The two wires in the connector are in a square looking connector that plugs into the back of the case.

They both use a main heavy feed wire and two smaller wires in that connector.

The one-wire ones use an internal regulator also. The alternator itself is identical to the regular internal one, just the regulator has been changed. All they do is insert the regulator from a truck (big truck) inside and that's it. It senses/regulates voltage without the extra control wiring. You can buy the regulator at any alternator shop and change it in your regular alternator in about 10 minutes. Or you can take your alternator to them and let them do it. Used to be able to buy the regulators for $20 or so. You just put it in and you don't use the other two little wires. They also sell a little jumper harness to use to make idiot light work right without the other wiring. The idiot light is actually a controlled resistance that is used to make a regular alternator function.

You want to take the main heavy wire from it (bigger the better) around and hook it directly to the starter where the main battery cable hooks. You can run it other ways, but that's the easiest.

Other oddity of one wires is that you have to 'rev" the motor slightly when you start it to "turn on" the alternator. It takes a certain RPM to get it started...but from then on...it stays on. Just the design of it. But they work fine.

You can also usally pick up chrome cases at any alternator rebuild shop. They will put you one together for a minimal fee with any regulator set up you want.


JIM

 

OK, let me clairify: I mean it is better to run an alternator, 3 wire with an internal regulator. This type uses a voltage sensing wire, a 12V switched wire and an output wire (Big Red one)

 

How would my gauge work? These one wire systems are just that one wire. Isn't the gauge hooked up to one of those wires?

 

Ok I just ordered a Power Master 3 wire internally regulated alternator. Thank you for everyones help. I hope to get it in time for a big cruise in middletown thursday. It has been laid up for 2 years undergoing a rebuild.

 

Be sure and read the MAD article, it explains how to hook the thing up. Email me if you still have questions

 

In a C3 with ammeter the gauge senses off the big wire, the others are not needed to make it work.