Generator rebuild

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TopGhia
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Joined: 21st April 2017 - 6:44pm

Generator rebuild

Post by TopGhia » 30th November 2017 - 8:14pm

My 12v generator gave up this week :(

I've done some diagnosis and 0V when checking for max voltage, also tried repolarising but gen didn't spin. Therefore it needs a rebuild?

I need advice on who can rebuild, sells reconditioned generators or upgrade to an alternator.

Thanks, Jon

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broady_6
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Joined: 13th January 2009 - 8:55pm

Re: Generator rebuild

Post by broady_6 » 1st December 2017 - 11:27pm

Have you checked the basics? Are the brushes ok, they need to be sticking out higher than the holder. If they're flush or lower they're worn out. Are the brush springs good? Or have they broken/relaxed? Is the com clean? Is the dynamo receiving the field signal to trigger it?
The sultan of swing

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broady_6
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Re: Generator rebuild

Post by broady_6 » 1st December 2017 - 11:31pm

If you are confident there are other circuit checks to do. You'll need a multi meter and some dismantling skills. Otherwise, I've had these guys do some rewinds for me and there work is faultless. They aren't cheap, but my theory is, if it works it works. And they're are no fuss guys, if you have a problem with something they've done, they'll put it right.

http://www.robsonandfrancisrewinds.co.u ... index.html
The sultan of swing

TopGhia
Posts: 12
Joined: 21st April 2017 - 6:44pm

Re: Generator rebuild

Post by TopGhia » 7th January 2018 - 10:35am

broady_6 wrote:
1st December 2017 - 11:27pm
Have you checked the basics? Are the brushes ok, they need to be sticking out higher than the holder. If they're flush or lower they're worn out. Are the brush springs good? Or have they broken/relaxed? Is the com clean? Is the dynamo receiving the field signal to trigger it?
Your first thought was right, brushes completely worn out. Simple job to replace them :D

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broady_6
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Re: Generator rebuild

Post by broady_6 » 7th January 2018 - 8:05pm

Glad to hear your up and running again. Get some photos posted! would like to see your car :)
The sultan of swing

TopGhia
Posts: 12
Joined: 21st April 2017 - 6:44pm

Re: Generator rebuild

Post by TopGhia » 28th January 2018 - 4:42pm

Had to replace the brushes again after approx. 1000 miles. Is it likely to be poor quality parts or could it be something else?

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Editor
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Re: Generator rebuild

Post by Editor » 29th January 2018 - 1:37am

How did the commutator surface look? Did you use some fine sandpaper to clean it up? When turning did there seem to be excessive sparking? I've a feeling I've seen some warnings with replacement generators that suggest the guarantee is not valid unless the regulator is also changed. I've no idea of the substance of that though. Try a complaint with the place you bought them from?
There is a way round for them that I only found out about through the USA mail-list. They have a notch on the top which you would think the springs sits in. I'm told it shouldn't! It should be the other way round. I think the reason is that Beetle dynamos rotate the other way, and there's something about the way the brush sits on th commutator as it goes round (a bit like leading and trailing brake shoes, maybe). It's worth a look anyway. Jim Adney jadney@type3.org has a charging pdf he may be able to forward to you.
Dave.

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broady_6
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Re: Generator rebuild

Post by broady_6 » 31st January 2018 - 8:20am

Could also be the bushes/bearings are shot allowing the core to move around causing brush wear.
The sultan of swing

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