Alternator getting hot?

Plow Away

New User
Just wired up my farmall A and I'm finding without the engine running the alternator is too hot to touch. Why is this happening?
My next question, the copper bolt that comes out of the starter on my A is lose and is allowing for poor connection which doesn't help the starting situation. Is that bolt broke? Can I buy new? or do I have to replace the starter? This is a 12v converted farmall, thanks for any help.
 
(-) ground, and you have a (-) ground alternator, correct?

One-wire or three-wire?

If "one-wire" it should NOT heat up when "off", period. If it does, you have bad rectifier(s)/diode(s) or a bad voltage regulator.

If it's a three-wire unit, the above problems apply PLUS the #1 terminal must have NO voltage to it after shutdown of the engine.

The copper stud on the starter, whether for the original mechanical starter switch or converted for use with a solenoid can be re-soldered or replaced as needed. You can do it yourself if you have access to an old-fashioned "soldering copper".

Otherwise, is there still an old-fashioned auto-electric shop in your area?
 
As Bob said, there's a good chance you have a shorted diode in the alternator. Take the battery lead loose and read resistance to ground using the "diode check" range of your multimeter. If you get continuity in both directions you have a bad diode. (On most multimeters, the diode check range actually displays volts, not ohms, by the way. A good diode will read about half a volt when forward biased and will be open reverse biased.)

The stud should be secured to the starter case by a nut. If the stud wants to turn when you tighten the nut, you can break the stud loose from the field winding which will require a trip to a shop for repair. If the stud is long enough, you can double-nut it to keep it from turning while you secure the mounting nut. That is, you have a total of three nuts on the stud: The mounting stud, and two more nuts that are tightened against each other. Now you can put a wrench on the double nuts and another on the mounting nut to tighten the mounting nut. Then remove the double nuts and hook everything back up.
 
I have one main wire coming off the alternator and going to the negative side of the ammeter. I also have two small plug -in wires that connect to the side of the alternator which run back to the starter switch.
So my copper post on that starter is very lose to the point of where I can twirl in in 360 degrees. So I need to take the starter off to have it soldered in copper?

Thanks for the help !
 
Plowaway........yep, turning stud, take yer starter motor in for a re-solder job. (yelowpages) Since it is massive, it takes a lotta heat to do the solder job. Let experienced folk do it. $20 (cheap)

Ennytime you have alternator problems/questions, take it into autoparts store for a "free" checkout. .....Dell
 
Here's how the wires from the connector need to be hooked up.

The #1 terminal must NOT have power after shutdown, or the alternator field will remain energized, making the alternator warm, and draining the battery .

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/424IH/Alternator%20Stuff/AlternatorHarness31.jpg">

You can substitute a 10 Ohm 10 Watt resistor or an "idiot light" for the diode, if you so desire.
 
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