Generator whine

Electrical issues
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Generator whine


Post by kell » Fri Oct 24, 2003 3:29 am

Description: I have got a rather loud whine coming from the generator

I've got a rather loud whine coming from the generator. With a thin rubber tube as a stethoscope I heard the sound loudest from the dustband on the end of the generator. When I took the generator off and ran the bike without it it didn't whine, so it's definitely generator-related. But the funny thing is when I took the generator to the bench to check it out it turns freely by hand with no rubbing or binding. Interested in hearing from fellas that have had generator whine and what caused it.
Being a congenital worry-wart I am wondering if it might have anything to do with the gears in the right side cover... if I have to open it up and work on it I'd want to do it now instead of next year.
In the interest of full disclosure: I replaced the armature earlier in the season. The new armature's diameter is just a hair's breadth bigger than the old one, and I had to polish the inside of the generator case and the iron slugs of the field where they bolt in to get clearance for the armature.

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Re: Generator whine


Post by WirePan » Fri Oct 24, 2003 5:19 am

Hey Kell!
My guess (educated or not) is it's either the bearing on the commutator end or the brushes themselves on the communtator.
Question, when you replaced the armature, did you replace the brushes? Even if you didn't replace the brushes, they need to be seated to the new comm. We use a comm stone to roughens the comm enough for the brushes to seat to the comm. In leu of a comm stone you can lightly sand the comm, the brushes will wear in the shape of the comm. and re-polish the comm.

Hope this helps!

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Re: Generator whine


Post by Sidecar » Fri Oct 24, 2003 8:18 pm

My generator whined from the day it was new. It was just on the bench after the relay stuck. Checked out perfect along with the gears on the right side.
I keep expecting it to explode or something........

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Re: Generator whine


Post by kell » Sun Oct 26, 2003 3:17 am

It makes sense that the sound would come from the commutator, 'specially since the stethoscope indicated the sound coming from right under the dustband...
So I had the genny out today and sanded the comm.
Had it out to try mounting those magnets (the ones Snake33 was kind enough to go get for me). What a beech! The magnets are very fragile... and so strong that it's impossible to put the generator back together without the armature smacking into one of the magnets and shattering it.


Re: Generator whine


Post by stiggyc » Sat Nov 08, 2003 1:27 pm

If the whine is in the gear side, it can come from the drive gear beaing a little tight to the idler gear in the case. Do to toleraces, some do and some don't.

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