I use the newer smaller GM alternator if space limitations require it but the old internal regulator three wire is more durable. On my home made tester which is a 1/2hp electric motor, a belt, a pivot pin to run through the alternator mount, a tension handle, and a battery is wired exactly as you describe: jumper #2 to BAT terminal, and a 10g wire from that same terminal to the battery. I don't wire in #1 but just touch with jumper to excite and then use a cheap amp meter that just slides over the wire to the battery for a reading or hook volt meter to battery for a more precise read. Sometimes when I'm going through the pile I just excite and touch the rear bearing with a hack saw blade, if it sticks then spending a little time on testing and cleaning is on the menu. These are tough old units so three in a row dead is unusual. Many times these old 3 wire units will self excite if rpm is blipped to 3 grand or so and the #1 connection is not necessary. My half dozen or so various cars, trucks and machines are just two wired but if I forget to tell another user to rev it to excite the battery will drain. Too lazy to wire in a light.
