Re: Farmall B anternator/ammeter

Posted by John T on August 01, 2007 at 16:51:17 from (66.244.83.147):

In Reply to: Farmall B anternator/ammeter posted by Dave H (MI) on August 01, 2007 at 14:47:29:

Dave, heres a few points:

A good and charged battery ought to actually read 12.6 volts sitting so depending on your meters accuracy and since it still dont budge off 13 (maybe its 12.6 but your meter isnt that accurate) sitting or running sounds like shes NOT charging.

The Load side of that ammeter, where the alternators big rear output stud is wired, should ALSO have the wire that feeds the ignition or lights, sooooooooo swap that wire from the ammeters other Supply side that feeds the switch over to the load side where the alternator is wired. The ammeters other Supply terminal ought to wire to the battery/starter as you already indicated. If loads like ignition are wired to the ammeters Supply terminal (as you indicate yours is) tht explains why she dont deflect over to - discharge not running if you turn on the ignition !!!!!!! WIRE THE SWITCHES TO THE SAME AMMETER TERMINAL WHERE THE ALTERNAORS OUTPUT IS WIRED

If thats a GM 10 SI 3 wire non self exciting alternator, its lil side No 1 terminal needs excitation voltage for it to begin charging (maybe thats why shes not charging???). The other lil No 2 terminal wires to the big rear output as you indicated. You didnt mention if your alternators lil No 1 side terminal is wired to anything????? IS IT???????

I will give you a written description of how to wire and excite the GM 10 SI so she will excite n charge, that may fix the problem !!!!!!!!

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 (WIRES UP TO THE lOAD SIDE OF THE AMMETER) . 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 you’re just now changing polarities.

Good luck Ol John T in Indiana

Replies:

• Re: Farmall B anternator/ammeter Dave H (MI) 17:30:17 08/01/07 (0)

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