Over charging
Here's my suggestion.
Key off.
Field wires disconnected (wires J2 & R3)
Use the ohm meter. Touch probes together to check for resistance. write that number down. Or if its an analog meter, zero it with the compensator dial.
Place one probe on the alternator housing. (Clean for good contact if needed)
Place a probe on each field terminal. Write down the resistance.
Then place the other probe on a field terminal. Write down the resistance if any.
Move that same probe to the other field termianl. Write down the resistance if any.
Possibility A
If there is continuity, zero or measureable resistance between either field terminal and ground, that is a fault.
If so, Remove the alternator.
Remove the brushes. Measure the resistance between the slips, and then each slip ring and ground using the same procedure as above.
If the slip rings have no continuity to ground, the fault was in the brush and terminal insulations. Replace them.
If the slip rings have continuity to ground, there is an internal problem.
Possibility B
There is no continity, infinite resistance between the field terminals and ground.
Short to ground must be in the R3 wiring or regulator.
Illustration of how current will flow with an isolated field alternator when the brush that should connect to the regulator is grounded.
Here's my suggestion.
Key off.
Field wires disconnected (wires J2 & R3)
Use the ohm meter. Touch probes together to check for resistance. write that number down. Or if its an analog meter, zero it with the compensator dial.
Place one probe on the alternator housing. (Clean for good contact if needed)
Place a probe on each field terminal. Write down the resistance.
Then place the other probe on a field terminal. Write down the resistance if any.
Move that same probe to the other field termianl. Write down the resistance if any.
Possibility A
If there is continuity, zero or measureable resistance between either field terminal and ground, that is a fault.
If so, Remove the alternator.
Remove the brushes. Measure the resistance between the slips, and then each slip ring and ground using the same procedure as above.
If the slip rings have no continuity to ground, the fault was in the brush and terminal insulations. Replace them.
If the slip rings have continuity to ground, there is an internal problem.
Possibility B
There is no continity, infinite resistance between the field terminals and ground.
Short to ground must be in the R3 wiring or regulator.