Alternator wiring

[NCmau]

I have a question about reconnecting an alternator to my JDM.The alternator is GM. How do I connect terminals 1 and 2? I believe that 2 goes to the positive main alternator wire, but 1 I don"t know. I am trying to put this tractor together.

 

[John T]

On the GM 10SI family of 3 wire internally regualted alternators:

The little NO 2 can wire up to the big rear main output stud/post.

I wire the little No 1 to EITHER the IGN output terminal on the Ign switch (one that feeds voltage to coil when ON) OR ELSE just right at the coils INPUT (NOT to distributor) terminal BUT TO PREVENT RUN ON ADD A 10 OHM SERIES REISTOR IN THAT CIRCUIT (between voltage source (ign switch or coil input) and the No 1 on alternator) or else a 5 amp 50 volt minimum PIV Diode or else a small incandescent idiot light.

The tractor was originally Pos ground but the GM alternator is Neg ground so you have to reverse battery polarity over to neg ground if not already there.

The coil leads also need reversed/swapped to match battery polarity i.e. for Neg ground the coils - wires to distributor and + wires to ign switch

If it has an ammeter its leads need swapped or it will read bass ackwards

I usually upgrade the charge circuit wiring to 10 gauge

You didnt ask about the coil so I didnt address it but post back if you have questions

John T

 

[NCmau]

Thanks a lot, John T. That's exactly what I needed to know.

 

[Anonymous-0]

I've installed side marker lights in many of these installations. The sockets are readily available as repair parts at auto parts stores. It adds the GEN light function in and for machines wired with ammeters.

Gave a feller this advice for his 9N that would not shut off. It had an alternator in it when he bought it. He always had to stall it, choke it or shut off the fuel to kill the engine. The guy who installed the alternator tried using an ignition resistor but it didn't work. Right idea but it was just too low a resistance value & the engine just kept running. I told him to take the resistor out & replace it with a side marker light socket & bulb. I told him it would light when the key was on before the engine started & would go out when the alternater came to life. It would also start blinking when he turned the switch off as the engine rolled to a stop.

He looked at me like I was from Mars but went ahead & tried it. He was most pleased.