alternator

[Anonymous-0]

My (new to me) Massey 97 came with a 3 wire alternator. I know the correct system would have a generator. Until I come across one of those I need to use the alternator. I can find numerous wiring diagrams. Most talk about running the sense wire to the idiot light. Don't have one and don't really want to add one. Can that wire be connected to the ammeter? Without it will the ammeter show anything?

 

[john in la]

Using a delco 10SI alternator

The 10gauge wire coming from the Battery post on the back of the alternator goes to the amp gauge. Other side of the gauge gets hooked to the starter relay or some where the battery + hooks.

The #2 or "S" spade terminal gets hooked to the battery post on back of the alternator with a 12ga wire.

The #1 or "F" spade terminal gets hook to the key switch or somewhere that has power only with the key on. This is the wire where the idiot light is hooked inline. If your tractor runs on gas and you do not use a idiot light you will need to put a one way diode in this wire to prevent power from back feeding the coil once you turn the key off. If your tractor is a diesel you can get it to work without the idiot light or a diode but beware.... If you ever get a break or loose connection in the 10ga battery wire the alternator will try to charge the battery threw this wire and will fry the diodes in your alternator.

 

[Bob]

<img src = "http://www.ndtel.com/~blweltin/Bob/AlternatorHarness3.jpg">

 

[mEl]

Very well done Bob, hope everyone has a printer. I don't know how common knowledge it is but there is a AC type regulator available for the 10SI series that has exceptional low RPM characteristics. It eliminates having to rev the engine to start charging. It requires removing the diode trio and adding two wires to excite the fields directly from the rectifier bridge. Available at knowledgable rebuilders very reasonable. If its running, its charging.

 

[John T]

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. The alternator output wires to the Load (NOT battery/starter) 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) output terminal or the coils high input (NOT to distributor) terminal, and in series with it place a 10 ohm 5 watt current limiting protection resistor . 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

 

[Anonymous-0]

That's awesome guys--thanks.