3-wire delco alternator

NOTE HOWEVER Ive seen n used em ALLLLL ways (diode or resistor or both or idiot light) n never seen one go bad, but a current limiting protective resistor sure couldnt hurt nuttin n she still works fine that way so "Thats my story n Ima stickin to it" lol Ive NEVER had a problem of trickle discharge on those GM 10 SI's which in theory a diode could prevent. Also, the idiot light systems (light versus diode or resistor) sure have some current limiting protection in the bulbs resistance (which my guess is wayyyyy more then the mere 10 ohms I use) and they still work fine !!!!! !!!!!

Although its not required to be so high power rated, I use a 10 ohm 5 watt or so resistor (in lieu of diode) just cuz it may have bigger easier to wire leads and similar, although its not required to be so high current rated, I use (ONLY if needed to prevent backfeed) something like a 5 amp 50 PIV Diode.

Bob n Bob M have those excellent pics n diagrams below, but all I have is my description of how I wire them. Again, either way works fine so its your tractor n you pay your money n make your choices as they say.

Heres how I wire a GM 10SI Alternator and remember, it requires NEGATIVE GROUND !!!!! !

The big rear main alternator output terminal goes to the wire that used to be connected to the BAT terminal on the Voltage Regulator or Cutout Relay. HOWEVER if that wire wasnt already upgraded, when I convert from a Genny to an Alternator, I replace that wire with a 10 Gauge and it runs from the alternators main output up to the LOAD (NOT to battery/starter) side of the ammeter. I also replace/use 10 Gauge from the ammeters other SUPPLY terminal to the battery/starter.

The little side number 2F Voltage Sense Terminal gets connected (use a short 14 jumper wire) right up to to and with the big main output terminal mentioned above.

For the little 1R side Excitation Terminal, run a 16 or so gauge wire from the ignition switches IGN (which is HOT ONLY when ignition is turned on) terminal and in series with it place a 10 ohm 5 watt current limiting protection resistor (dont really need that much wattage power rating, but they are heavy duty built and easy to wire). Then in the rare event the tractor continues to run cuz of alternator backfeed when the ignition is switched OFF, I add in series a 5 amp 50 PIV minimum Diode. The diode must be wired with negative cathode end to the alternator and positive anode end to the switch. Again, the ratings are not that exact but about any diode over a few amps and 50 volts or so works.

Dont forget to change the battery to negative ground and the coil needs to be wired so the negative goes to ground via the distributor points and the positive gets power from the ignition switch and you have to reverse ammeter leads also if your just now changing polarities.

Good luck Ol John T in Indiana

I often refer people to the MAD electrical site, as the other poster did, and the information there is GREAT.

However, on a tractor, with it's short wiring runs, and (typically) lack of electronics and high-draw accessories, most of us just connect the #2 "sense" lead to the large output stud of the alternator, as you are proposing.

So, keeping it simple works just fine on a tractor, and simple car applications, too, although there's certainly nothing wrong with the remote sensing suggested on the MAD site.

Have you checked out BobM's Farmall wiring diagrams?

• BobM's place

http://albums.photo.epson.com/j/ViewPhoto?u=4001561&a=30065733&p=60243702

Link

Also.. a 194 lamp inline will work just fine too.. just like god and GM intende dthe idiot lamp to work.. trailer marker lights are great.. they hav ethe little wires already there to hook up.. usually like a buck or so at the truck stops.. etc..

A fellow here named /Bob/ makes the neato little harness you've seen pics of.

Soundguy

• Hobby farm