Generator - test on tractor?

Had the generator rebuilt and it measures fine at the shop, but I'm getting no voltage ouput when mounted.

I installed a new voltage regulator and a new battery, too. I've checked continuity in the wiring harness and verfied all of the connections. I've also polarized by arcing the Batt & ARM connections on the regulator with all wiring in place and the key "on" and the tractor NOT running.

I can start & run the tractor, but I see a "slight" discharge on the ammeter and no increase in voltage on the battery when the tractor is running. I think it's just running off the battery. (By the way, the ammeter shows negative when the starter is running, so I believe the ammeter is working.)

I have a slight suspicion the generator may have been rebuilt as a B-circuit genny based on a comment made at the shop. But... I don't know how to check for that.

So...Since I can start the tractor, is there a simple way to test just the generator for output and to see if it's an A-circuit or B-circuit?

I'm thinking something along the lines of "disconnect all generator wires, start tractor (spin the generator), jump field to ground, measure voltage across ARM and GND studs."

Thanks in advance!!!

Russ

Turns out my 8n generator was a b-circuit. I don't know if it was rebuilt wrong or replaced at some time in the past. Physically, it looks like the right generator, but I can't find any part number on it.

So, after buying a new b-circuit voltage regulator (for an NAA) and polarizing correctly for b-circuit, everything comes right up.

Short story, always take the generator and voltage regulator to the shop as a pair. He could have saved me a lot of time had I done that the 1st time.

Russ

Everything you need to know.....

"A quick test to see if the generator is at fault is to jumper the field terminal directly to ground. If your charging rate jumps, your generator is probably good (note, one minor complication to this simple test is if your cutout relay points don't close, the charge rate still won't jump even with a good generator, remove the cover of the regulator to make sure). It is amazing how many generators are replaced when they really are still viable."

Remove the field wire from the Generator "first" then JUMPER ground to the GEN field post (full fielding)

If GEN outputs you have type A GEN. If the GEN doesn't output move the JUMPER wire from ground
to Armature (voltage) and if that results in MAx Output you have a class B Generator.

Hope This Helps,