Alternator and electrical basics with a multimeter
This is a simplified circuit of the pre 70 alternator / regulator
At the top, labeled "ignition" is coming from the ignition switch dark blue "run" wire which also feeds the ignition system. Through the VR WHICH must be grounded, out on the field FLD terminal, and to the only terminal on the alternator through the green wire. The second field terminal shown to ground normally does not actually appear external to the alternator. IF YOU buy a more modern replacement, THAT SECOND FIELD may need to be grounded externally. PHOTOS are the only way
The RED "batt" wire is oversimplified. It does NOT go direct to battery, but rather through the ammeter circuit as I mentioned earlier
This is a simplified circuit of the pre 70 alternator / regulator
At the top, labeled "ignition" is coming from the ignition switch dark blue "run" wire which also feeds the ignition system. Through the VR WHICH must be grounded, out on the field FLD terminal, and to the only terminal on the alternator through the green wire. The second field terminal shown to ground normally does not actually appear external to the alternator. IF YOU buy a more modern replacement, THAT SECOND FIELD may need to be grounded externally. PHOTOS are the only way
The RED "batt" wire is oversimplified. It does NOT go direct to battery, but rather through the ammeter circuit as I mentioned earlier