Ok first a bunch of questions..
- What car
- What year
- What engine
- What modifications
- Did it ever work correctly
As for the voltage regulator. Depending on car it is located on the firewall by the master cylinder, (black can with two wires) this is the old style electro-mechanical single field wire type
Later models had an electronic VR it's mounting location I'm not familiar with. It has 2 field wires.
The alternator you have is commonly refered to as a "square back" it is a later model.
It seems to be internally wired for a single field wire.
Electro-mechanical voltage regulator
View attachment 1715601104
Electronic voltage regulator
View attachment 1715601105
Round back alternator
View attachment 1715601106
Square back alternator
View attachment 1715601107
