An A/C Delco rep came to the parts store I worked at to host a seminar on alternators and charging circuits. Was pretty interesting.
He demonstrated how the alternator could (would) spike a high voltage if the battery was removed from the circuit.
He also explained how the old three wire Delco operated and why Delco liked to use a sensing wire from a remote location in the wiring harness. (Most people make a short loop from one terminal to the other on the back of the alternator)
He also explained that the back of the alternator needed a good ground rather than depending on the 4 bolts that hold the two halves of the alternator together providing that ground.
So GM put a bracket and bolt on the back of the alternator to not only help to stabilize it, but to provide a good ground path for the end of the alternator doing all the work.
Was interesting, and several year back, so some now is a bit foggy. But I learned several things I had never really thought about.
Good luck to you on your endeavors.
