Stock alternators are Delco 27SI isolated negative. There are 4 required wires, battery positive, battery negative, excite voltage and voltage sense.
If the excite and sense are wired to the battery positive, the alternator will charge, at reduced output.
Excite and sense are in a two pole plastic plug in the side of the alternator. Battery connections are in the back.
Aside from specialty regulators, this alternator will not function without both excite and sense wires connected and functional.
Excite circuit powers the generator lights with key on engine off. Key switch gives power to the light which then flows to the regulator. If current output of the diode trio is less than the current through the light, the light illuminates. Once the alternator is producing current, there is no flow through the light.
Voltage sense provides for full charge voltage at the battery. The alternator positive will be at a higher voltage than the battery when output current is high. This is because a #6 wire, 4 feet long, has a small resistance to a current of 100 amperes. The current flowing through the sense wire is just a few milliamperes, there is no measurable voltage drop.