gernerator question

Trying to get the 6 volt generator working on my A. When I get the wiring unhooked and apply power to the generator as described in the troubleshooting section of instructions that frequently come up here it turns and passes the test so I'm sure the generator is OK. But if I have the tractor running and everything connected all I can get is about 0.2 volts when I try to measure at the gen post on the generator.I'm expecting 7 volts at this point - what am I not understanding?

The first issue is does it "motor" slower with the field grounded or not. Just motoring is .5 of the test.
The second is does it charge when the field terminal on the gen is grounded? if so the issue is VR or light switch control if no VR. Jim

It needs to pass BOTH Genny Motor Tests. 1) If you ground the field and apply battery voltage across ARM and case ground and she spins good and smooth, the armature and brushes and bushings are likely okay 2) Then if when you remove the Field from ground she spins up, then likely the Fields are good and intact. If it passes BOTH tests it ought to charge.

With her running, if you dead ground the Field and she then charges (that says genny itself is okay) but NOT otherwise, the problems a bad VR or not well grounded VR or (on cutout relay and light switch control systems) the LHDB light switch isnt well grounded or bad or the wires bad from FLD on Genny up to the switch. If its a no light tractor with a cutout that has the F terminal, that needs wired to FLD post on genny, thats where Field gets its ground.
If the FLD isnt grounded (VR or LHDB switch or F on relay) NO CHARGE

A good 6 volt battery ought to read 6.3 volts just sitting there and if hooked to a good working charging system at fast RPM it should raise to at least 6.5 up to 7+

The open unloaded voltage from ARM to case frame isnt as important as to what voltage the battery raises (per above), thats the REAL test, but if its as low as .2 unloaded shes notttttttt working.

Heres more

John T
John Ts Troubleshooting

With the old 6 or 12 generators everything has to have a good ground to the frame.

Those that have the voltage adjustment Hi or Lo on the light switch, the light switch and box cover all have to have a good ground to the frame including the generator and VR or cutout relay box. All this has to get back to the battery of course so all these connections have to be good and clean. Some people I have seen use a ground wire and hook the switch, VR and generator all together then run it to the ground wire on the battery. Just my 2 cents.