Utterly confused charging system

[barros57]

ok, so here's the deal. I really hope someone on here can help me out here.
The tractor is later model 50-52 ford 8n (or so I think).

Anyways, the the charging system is not charging. I thought the generator might be bad, but I took it off and connected a battery to it and it spun just like an electric motor so It seems fine to me.
The tractor bogs down and dies when I touched the voltage regulator (It has rubber feet which isolate it from the frame which are worn). The voltage regulator number is VRR-4008-A. I tried polarizing it, but there are no markings on this voltage regulator to tell which terminals are which.

1) The battery negative was grounded but I thought these tractors were 6v pos ground? is this wrong?
2) I just bought a voltage regulator on ebay that I am hoping will work it is an A-circuit 6volt for a ford 8n. is this the same as my frame isolated VRR-4008-A voltage regulator?
3) 2 brush / 3 brush generator?

Here are some pics

 

[EssexBoy]

This may help you.
8N w/Front Mount Distributor (12 Volt Conversion)

 

[EssexBoy]

8N w/Side Mount Distributor (6 Volt)

 

[Soundguy]

a late 8n is a 2 brush genny, a circuit.

polarize genny by jumping bat to arm.

note.

when you motor tested the genny.. if it spun by just hooking up bat to arm, and grounding frame, there MAY be a problem. generally, the field also needs to be grounded to spin. without the field being grounded it can spin for 2 reasons.. 1, enough residual magnetism in the field pieces to get her moving, 2, the field coil is shorted to the case somewhere.


your vreg part number VRR-4008-A is equal to a ford 8N-10505A

either vreg will need a reference to chassis ground.. so make sure it is intact.

post back if you need more help

soudnguy

 

[barros57]

Thanks! That really helps! I took the generator all apart last night and cleaned all the terminals up and repainted it. I checked for continuity to see if any of the coils were shorted or grounded to the case, but everything seems to be in good working order.
The new voltage reg. should come today so hopefully everything will be working by sat. Thanks again!

 

[Soundguy]

post back if you hit a snag.

ps.. since you have disassembled your genny.. you will need to repolarize it.

mount it so it is grounded.. hookup ground wire if it has a space on it. some have a ground post bear the field post.. some don't.

jumper a wire from bat hot to armature. just a quick 2 second spark.. then hookup vreg and check ammeter for charge at mid and hi throttle.