Did i f up my generator ?

[hobbybob517]

Hi guys need a little advise here,

Have à charging issue, so i checked voltage on the generator,
Measured 0.7 volts jumped df to ground and had voltmeter on D+ and ground.

Revved engine up to about 3000 rpm.

So here's the thing, i tried to polarize my gen, i might have done it wrong
I connected à battery plus to D+ and the neg to Df the generator spun ok
I just spun iT for 3 seconds now my generator meassures 1.2volts at 3000 rpm.
Soooo.......what's up?
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[VW_Buggsy]

http://www.vw-resource.com/generator.html

Sounds like you did the test properly and the polarization properly. The polarization thing is just to set up an initial current flow as I understand it and as long as you're getting any positive voltage you shouldn't need to do it again (I believe).

Did you check the brushes on the generator? That's the little black blocks you can see inside a metal sleeve through those windows on the generator that rest on the armature. They do wear out and sometimes the little springs that hold them to the armature weaken or break. They need enough meat on them to stick out up past that sleeve and the springs that hold them in need to be pushing them onto that armature well.

While doing your voltage test you can try to squeeze the brushes more tightly onto the armature and see if the voltage increases... of course you could rip a finger off trying to do this too so it's at your own risk.

If it's not that, you're beyond my skill level. Good luck!

[hobbybob517]

Thanx for the reply ,
I did check my brushes and they are fine.
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[hobbybob517]

Is there anything else i can check/test?
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[VW_Buggsy]

Well, from that tech article:

"If you don't get the high voltage (up to 35 volts for the 12-volt generator or 20 volts for the 6-volt generator), the generator is probably faulty."

So, it sounds like it's probably faulty. Stuff breaks, 'specially really old stuff.

Maybe a wiser head than mine can help bring it back from the dead.

If the armature where the brushes contact are dirty that can cause problems. You can take some sandpaper/emery paper and rotate the generator by hand while pressing the sandpaper on it to clean up the contact face and sometimes that helps.

I haven't had too many issues with generators and when I have I've just swapped them out (I have a bunch I've acquired from people swapping to alternators).

Good luck with it.

[hobbybob517]

Yeah i guess it's broken
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[runamoc]

[VW_Buggsy]

I've always put DF to ground to do this and that is what is described in the tech article I linked to above in both the voltage test and polarization procedure:

For voltage test:

[hobbybob517]

[Luft kühl]

http://www.speedyjim.net/htm/gen.htm

[hobbybob517]

Yup, that's what i did. Guess its broken.
I can get it rebuilt localy , i'll drop it off next week

Thanx guys
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[hobbybob517]

I got my new generator installed today, and it works!

Thanx again for the help.
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