Generator wiring without battery?

Crazy Horse

Well-known Member
I have a Farmall A here that I have the 6V 3rd brush (positive ground) original generator installed on it and belted up even thought the rest of the tractor wiring isn't finished. I don't want to mess with getting that inside generator belt on later so here's my question ........

Will spinning a generator without being wired into a completed charging system be harmful?

How does a person wire the generator to prevent damage (if spinning it without wiring can be harmful)?
 
Just remove the belt from the pulleys and tie it up till you get a battery and finish the wiring thats what i do as you can tie the belt so it wont get tangeled. They dont recomend running the gen without a batt.
 
(quoted from post at 12:41:26 05/03/13) I agree. Jim
agree with gene & curt & maybe even Jim........just don't know Jim's position on the matter.....or who Jim is? :) :?
 
Jim is Janicholson, one of your brighter electrical guys on the board. On electrical matters, I usually read the question, look for answers by him, John T and a couple others, read them, and then move on.

And you'll notice I NEVER post answers to electrical questions- I know when I'm over my head.
 
I didn't read it right........He was saying I agree (with curt), not as my brain perceived, 'I agree with Jim'..
so, I guess that means I agree with both curt, Jim .........and even gene! :)
 
Are you going to be running it hour after hour or just to move the tractor? Even with the field wire off there is some magnetism in the poles that the armature will try to produce a currant from.
 
Ahhhhhhh but I love it when you weigh in on legal questions Mike, I dont practice law all that much nowadays like you still do, so get as rusty on law as I do electricity grrrrrrrrr

Co Counsel John T
 
Like the other sparkies I dont see spinning that 3 brush genny with no load/connections is going to overheat or otherwise trash it. The Field strength absent any field current (no place to flow with FLD post sittin there in open air) is pretty weak (thus low genny output) since the field poles residual magnetism is all you have to work with (as our friend Teddy talks about). With the ARM to GROUND possible output current path also not in use, I dont see the armature as overheating either.

John T
 
The 3 brush generator does not have a field post.A 3 brush generator will run away to 18 volts without a battery load.
 
(quoted from post at 18:50:07 05/03/13) The 3 brush generator does not have a field post.A 3 brush generator will run away to 18 volts without a battery load.
here are 3 brush generators without a Field post AND there are 3 brush generators with a Field post. His apparently has one as his A-Farmall should. If his did not, then running it with no connection would overpower the fields & perhaps other items & burn it up shortly, but that isn't the generator that he asked about.
 
Typical Class A Generators, 2 or 3 brush, have an external FLD post. It takes a connection from there to a ground source, via a Voltage Regulator or Low/High light switch manual control, to complete the Field circuit. The beginning of the field circuit (first winding) begins at the third brush,,,,,,,,to and through the first coil,,,,,,,to and through the second coil,,,,,,,,to the FLD post,,,,,,,to ground via the VR or switch

Some Class B Generators Ground the field internally and field current is regulated by varying the voltage on its input.

In all my years as a used tractor dealer and many many makes n models of Generators I had to repair grrrrrrrrrr 2 or 3 brush gennys had external Field posts.

Of course, never say never, since there are different types and brands of gennys out there some 3 brush may use an internal ground and NOT have any FLD post, but of the tons I owned and worked on over the years (all different brands)they sure did.

Hope this helps, post back any questions

John T
 
(quoted from post at 20:41:56 05/03/13) Typical Class A Generators, 2 or 3 brush, have an external FLD post. It takes a connection from there to a ground source, via a Voltage Regulator or Low/High light switch manual control, to complete the Field circuit. The beginning of the field circuit (first winding) begins at the third brush,,,,,,,,to and through the first coil,,,,,,,to and through the second coil,,,,,,,,to the FLD post,,,,,,,to ground via the VR or switch

Some Class B Generators Ground the field internally and field current is regulated by varying the voltage on its input.

In all my years as a used tractor dealer and many many makes n models of Generators I had to repair grrrrrrrrrr 2 or 3 brush gennys had external Field posts.

Of course, never say never, since there are different types and brands of gennys out there some 3 brush may use an internal ground and NOT have any FLD post, but of the tons I owned and worked on over the years (all different brands)they sure did.

Hope this helps, post back any questions

John T
ord, "N" series tractors from 1939 up until 1947 used four different generators having NO Field terminal (only an armature terminal ) & of course ground. Field coils connected to 3rd brush and to ground inside the housing. Used simple cut out, without VR.
 
I believe thats correct JMOR, of the ones I recall I think it may have been Fords (maybe a few other oddballs) with no external FLD post and suspect they had the internal grounded Field windings I spoke of above. Of the literal hundred of tractors I bought and sold and repaired gennys FEW WERE DARN FORDS I WAS NOT A FORD MAN LOL It was much more typical to have 3 or 4 brush gennys WITH the FLD post fer sure.

As always, fun chattin with ya, take care now

John T
 

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