Wiring an Alternator

DelMN · Sep 30, 2023

I've seen it may times on here, but now I can't find one. I would like a wiring diagram for a single wire Delco alternator for my Farmall M. Thanks!

used red MN · Sep 30, 2023

In the link is the YT run down for the conversion. I think most Ms have the heavy contact push button switch to operate the starter. So the lead the diagram shows connected to the starter goes on the starter switch terminal that is on the battery cable side. On a one wire you can just ignore the wiring to the 1 and 2 terminals out of the side of the alternator. If you are going from positive ground to negative, which needs done for an alternator install you have to swap the wires side to side on the ammeter. This is covered under number 4 in the Testing section.
YT Farmall M 6 to 12 conversion and install of alt.

This post was edited by used red MN on 09/30/2023 at 06:50 am.

BarnyardEngineering · Sep 30, 2023

The above article details a 3-wire alternator setup. The wiring is similar, but simpler.

Bob M's wiring diagrams are still floating around out there but they're not all in one place anymore.

This is the single-wire alternator version:

Traditional Farmer · Oct 1, 2023

The Battery wire off the alternator needs to be run to the battery or to the end of the battery cable on the starter solenoid directly,usually calls for at least 12 ga. wire.

used red MN · Oct 1, 2023

..The Battery wire off the alternator needs to be run to the battery or to the end of the battery cable on the starter solenoid directly.. I guess you can do that if you DO NOT want the ammeter to show what it is charging. I would not recommend that. If you decide to use a volt meter wiring it that way would be acceptable. Most recommend a 10 gauge wire off the alternator.

Traditional Farmer · Oct 1, 2023

I'm saying what the instructions with the alternators say to do,no wonder people have so much problem with one wire alternators.Anyway I don't have to be constantly assured the alternator is charging if I did I'd get one of those $10 3 light testers that Harbor Freight sells and hook it up, already comes with clips and a magnetic back.

used red MN · Oct 2, 2023

(quoted from post at 22:37:00 10/01/23) I'm saying what the instructions with the alternators say to do,no wonder people have so much problem with one wire alternators.Anyway I don't have to be constantly assured the alternator is charging if I did I'd get one of those $10 3 light testers that Harbor Freight sells and hook it up, already comes with clips and a magnetic back.

If that works for you great. Millions of vehicles and machines have been built with the alternator charge going through the ammeter and ran fine for years. In your defense millions more have been built wired as you suggest with only and idiot light. And lately millions more wired as you suggest utilizing a volt meter. If he was going to go around using this tractor daily jump starting other units with dead batteries and using heavy jumper cables you would probably be right. The wiring shown in the diagram may not be his best choice and his ammeter would not last long. Used like a normal old tractor wiring it as shown will be fine. And when he cranks it up and the ammeter swings up showing a healthy charge he will enjoy that warm fuzzy feeling. To each his own.

Wiring an Alternator

DelMN

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used red MN

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BarnyardEngineering

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Traditional Farmer

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used red MN

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Traditional Farmer

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used red MN

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