1950 John Deere A flashing charging system

[jrmyers]

This tractor is evidently positive ground, I` pulled the generator and relay to clean up and inspect. It`s been years since I have flashed the fields in a generator and wasn`t sure that most likely it had to be done . Any way is it needed and what`s the process , battery was disconnected when I pulled the two, John Deere tech manual doesn`t address this, if they did I couldn`t find it. So maybe you know something that I don`t, THANKS JR.

 

[560Dennis]

In YT article few things to remember at bottom

Third-Brush Generators

forums.yesterdaystractors.com

 

[Mike(NEOhio)]

Does it have a cutout relay or VR? My 51 A has a four- brush gen and VR but I'm not sure it's original. Yes, originally positive ground and you DON'T flash the fields. Polarize from battery negative to Armature terminal on the gen.

 

[jrmyers]

My generator is a delco remy 1101777-9J20 2brush, 2 pole with external regulator , 12 volt ,regulator has one wire underneath to armature, field lead ,generator to reg. , bat. lead on reg. I assume negative and a L marked connection to light switch and battery with a positive ground. That`s weird, like driving down the road on the left side .First one I`ve seen in years. Do you disconnect lead at generator or not before you do this? JR.

 

[Mike(NEOhio)]

My generator is a delco remy 1101777-9J20 2brush, 2 pole with external regulator , 12 volt ,regulator has one wire underneath to armature, field lead ,generator to reg. , bat. lead on reg. I assume negative and a L marked connection to light switch and battery with a positive ground. That`s weird, like driving down the road on the left side .First one I`ve seen in years. Do you disconnect lead at generator or not before you do this? JR.

Pretty sure mine is like that buy I'm away from home right now. I can check when I'm back home (if I remember) and post back. You don't need to disconnect anything when polarizing. I'm having hard time following your sentence on the connections but you seem to be confused. Try this:

https://electricalrebuilders.org/wp-content/uploads/2025/10/John_Deere_A-Wiring-Diagrams.pdf