an electrical nightmare , please help , 1972 dart
I don't understand. This IS a standard "70's" Mopar alternator? And not something like a powermaster? Can you shoot a photo of it showing the back and terminals?
The field is a simple electromagnet, connected to the two field terminals. The light blue wire supplies 12V from the switched "ignition run." With that connected, and key "in run" you should read "battery" at the green field wire when disconnected at the regulator. The VR controls "the amount of grounding" on that green wire and that controls alternator output. IF the alternator is charging with the VR connected, either
the green field wire is grounded
the field is grounded on the "end" opposite the blue 12 supply wire
or this is an aftermarket alternator with a built in regulator, and IT is acting up
EDIT:
With both field terminals disconnected . With the meter set to the 200 range in ohms , it read 54.3 with one probe on the lower field terminal blade ( where the blue wire goes ) and the other probe on a fender bolt ground .
This right here says there is continuity from field to ground. The field may actually be shorted to the rotor itself, and grounding through the bearings. Try removing both brushes, and probe directly on the slip rings. In other words, with brushes removed, and with one probe on either slip ring, other probe on alternator case, should be open/ infinity
Inspect the brushes/ brush holders carefully for shorts.
