Alternator overcharging

An internally regulated alternator the aux terminals are labelled "1" and "2". Also the internally regulated's aux terminal spades are in line (like this: - - ) vs the the older units have the aux terminals arranged in parallel ( | | )

Anyway you need to either wire up the correct regulator or else swap in an internally regulated alternator.

John T

So disregarding the terminal labels, the most reliable way to determine whether an alternator is a 10DN (externally regulated) or a 10SI (internal regulator) is to look at the arrangement of the aux spade terminals as mentioned in my previous post.

John T

I believe the terminals on those were oriented "I I", instead of the "- -" we are familiar with on the later internally-regulated units.

So, that explains the dual markings on some of the cases.

If the alternator will accept a connector with the terminals "flatwise", like the one in the photo below, I believe it will always be the correct, internally-regulated unit.

I will try to run down one of those oddball alternators, and post some photos just to clear this up. It may take me a few days!

John T

Heres my wiring instructions for the GM 10 SI it sounds like yours is wired dead wrong, hope its not hurt.

Heres how I describe wiring them. Bob M’s great diagrams puts it in pictures, which they say is worth a thousand words, so take a look and see for yourself.

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