The Stovebolt Site Forums The Shop Area The Electrical Bay Self-exciting alternator?

Anyone ever use a self exciting alternator on an AD truck. I understand that no voltage regulator is needed and the CS series alternator will begin charging as soon as the pulley begins to turn? The one I purchased is a 60 amp Delco alternator from Certified Auto Electric in Bedford, Ohio.

Tim

Tim,

I have used a 50 amp 12v 1-wire alternator (that is now 18 years old) that my friend is still using on his 54 truck. It gets "excited" ("turn on point" or "cut in") at around 800 rpm. Once it starts charging, it continues to charge at all RPM until the engine is turned off.

A one-wire alternator has an internal voltage regulator.

To simplify wiring and to fake an original appearance, some people have taken the "guts" out of the voltage regulator and make the one connection inside the empty voltage regulator.

I have a 6v negative ground Powermaster one-wire alternator that I might try on my Suburban. They also make a 6v positive ground 1-wire alternator (perhaps of interest here to GMC owners).

Tim,
The above posting is correct in that the one wire alternators have regulators built into them. Most common was the Delco 10SI used in the 70s and 80s as they were and still are very reliable. All of the 10 SI alternator were basically the same, different amperage ranges but basically built the same. They all took the same internal voltage regulator. To make one a self exciting alternator with NO wires going to the regulator you change the regulator. It excites off of the rpms. With this being said there are different self exciting regulators available and it all depends on which one the builder is using. When the self exciting regulators first came out they werent worth a dime on low rpm applications such as tractors etc. Because of the cut in at around 800 rpm or so. Since then aftermarket has come out with different versions, low rpm cut in regulators etc. They will kick in at a couple hundred rpms. The only way, that I am aware of, to get one to kick in about as soon as the pulley starts turning is to use an aftermarket regulator that is a small box that mounts on the outside thru bolt of the alternator. Its a special regulator that will actually allow the alternator to charge just about by spinning it by hand. Its more costly but works great on low rpm applications. As far as I know this type of alternator has to be custom built but so do most self exciting ones. Just an FYI and my experience in building them years ago.
Ken

Cut-in RPM consideration:

- Idle speed is usually 450-500 on otherwise stock truck.

- When you start your truck, your choke/throttle setting usually results in a start-up idle speed between 750-1000 RPM

- Start-up idle speed normally "excites" one-wire alternator.

The new 12SI ones are completely self exciting, start charging as soon as the belt starts turning, and all internally regulated. One wire but they have the other two in case you want to wire it like your old 3 wire. If you get a black powder coated one, they even look halfway decent.