H Charging Issue

[ThePunisher]

Well, I've been lurking for a while here, but just joined today in hopes that someone can shed some light on a mystery. I have a 1940 H that the previous owner converted to 12v with a gm 3 wire alternator. In place of the amp gauge was just the light that goes out once the alternator excites. I installed an amp gauge and moved the light to the side, and everything was great for the last 3 weeks. The light was on when I started the tractor, then would go out once I got past half throttle and the amp gauge would show positive amperage. Yay! However, out of the blue today, I reved the motor up but the light will not go out no matter what I do. What should I be looking for here? I've checked all the wire connections and nothing seems to be loose or off...any ideas?

[Eugene]

Alternators do go bad. Remove and have tested at your local auto parts store.

If bad replace with a single wire Delco clone.

[ThePunisher]

Fair enough - I'll see what the tests show. Thanks for the quick tip

[Eugene]

I use to repair my own alternators. Until the repair parts cost more than a rebuilt alternator with a 1 year warranty.

I have only one tractor left with the 3 wire Delco alternator. As the 3 wire alternators failed, replaced with the 1 wire. Have to remove or tape up two wires. Installation is dirt simple.

No in town NAPA store. The Delco single wire clones were purchased from a Federate affiliated auto parts store. The alternators start charging upon engine start up, even at low RPMs.

[ThePunisher]

Well, turns out it was simple - the bracket that adjusts the tightness was broke off at the motor side - when I took the alternator off to have it tested, I discovered the bolt on the bracket had sheared off. Even though the pulley was still turning, it was slipping at higher speeds and would not turn fast enough to excite the alternator. Alternator tested good, and I fabbed a new bracket and all is well now.

[ThePunisher]

That being said, what would I need to do to convert to a one wire? I assume I would still keep the number 10 wire off the alternator to the amp gauge, but what about the others? How does that work?

[havoc1482]

If your current setup works fine, why change it?

[Matt Kirsch]

If the day comes where the 3-wire alternator stops working and you convert to a 1-wire, all you have to do is remove or tape off the other two wires.