51 Deere B-is this an alternator or generator?

[ndgregor]

This tractor is equipped with an external voltage regulator and I'm trying to determine if this is a 12 V generator or alternator. Only a field and armature post on it. Does anyone have any idea or ways to determine?

 

[Looking4new]

Looks like a generator to me. How many cells on the battery? How many caps to remove? 3 caps=6 volts, 6 caps= 12 volts

 

[Shaneard]

That is a generator. Are you trying to get it to charge? Are you wanting to keep it original? If not switch it over to an alternator with built in regulator. Here's a link to one I just put on a Farmall Cub and it works great. 1 wire to the amp gauge for charging and that's it.
https://www.dbelectrical.com/products/chevy-mini-alternator-denso-street-rod-race-1-wire-12180.html

 

[Johnny g]

That is a generator. Are you trying to get it to charge? Are you wanting to keep it original? If not switch it over to an alternator with built in regulator. Here's a link to one I just put on a Farmall Cub and it works great. 1 wire to the amp gauge for charging and that's it.
https://www.dbelectrical.com/products/chevy-mini-alternator-denso-street-rod-race-1-wire-12180.html

What he said. ↑↑↑

 

[ndgregor]

I have not decided yet what to do. Trying to figure out what is going on/how it is wired. It is using a 12V battery now, so clearly it is not an original set up. I suppose it would be worth testing the generator to see if it works first.

If I use that alternator you mentioned, what wires get run and to where? I assume one has to go back to the battery? Is it only one wire to the ammeter?

 

[Shaneard]

If you switch to the 1 wire alternator you run that one wire to your amp gauge and the other wire coming off the amp gauge goes to the battery. It really is only one wire but the gauge makes it 2 wires since it has two terminals so you can measure your amperage. It really is simple.

The alternator I posted a link to doesn't need a switch to turn it off or on and it won't drain your battery over time. Your on off switch goes to your distributor or magneto depending on which one you have.

 

[ndgregor]

Thanks for the information, that does sound like a pretty easy route. I would need to figure out some way to mount it would be the only issue.

If this is a 12V generator, should the tractor still be wired as positive ground? I have not confirmed it is a 12V generator, but there is a 12V battery installed as a negative ground. I plan on bench testing the generator tonight to see what kind of shape it is in, but I am not sure how to determine whether it is 12V or 6V without running the tractor.

 

[milkman]

That is a generator. Are you trying to get it to charge? Are you wanting to keep it original? If not switch it over to an alternator with built in regulator. Here's a link to one I just put on a Farmall Cub and it works great. 1 wire to the amp gauge for charging and that's it.
https://www.dbelectrical.com/products/chevy-mini-alternator-denso-street-rod-race-1-wire-12180.html

That alternator you posted looks like the same size as the small Kubotas use. I think this would work instead of the little dynamo on the BX. I see the one wire, but what plugs to the two wire plug on the back of the alternator?

 

[Shaneard]

That alternator you posted looks like the same size as the small Kubotas use. I think this would work instead of the little dynamo on the BX. I see the one wire, but what plugs to the two wire plug on the back of the alternator?

On this particular alternator nothing goes on the plug on the back. All you do is hook the one wire on the post labeled "B".

 

[Tx Jim]

'51 JD B came from factory with a 6 volt electrical positive ground electrical system. If changed to alternator it will need to be changed to negative ground as there are very few positive ground alternators.