Author Topic: Confused Dynamo rebuild  (Read 1710 times)

Offline Marqs1979

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Confused Dynamo rebuild
« on: 20.11. 2013 11:55 »
Was a bit confused when I was going to rebuild my dynamo. On the new shaft it was a keyseat (I'm not sure what it's called in English?) For a woodroof key?
But on the old there is no such a seat. Hope you understand what I mean: (Sorry.
Is it preferable? Or should I run without  Woodroof like the original?

I work in a workshopso it's no problem for me to make a seat in sprocket.

Anyone feel free to correct my poor technical English: (

http://forumbilder.se/CG4MC/img-6898.JPG

Offline a10gf

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Re: Confused Dynamo rebuild
« Reply #1 on: 20.11. 2013 12:20 »
Hello, it's good if the key is there (no risk of slipping), but if you feel that you can secure the sprocket without a key it'll work fine. And as there is no timing\alignment involved, there will be no damage (only loosing the charging) in case it should slip.

But basically, better with a key than without, then you won't have to later have to do the work for a key in case it was needed :O)

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Offline muskrat

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Re: Confused Dynamo rebuild
« Reply #2 on: 20.11. 2013 18:24 »
G'day Marqs1979.
I agree with a10gf for another reason. Those taper fit sprockets can be a real bugga to remove, being so tight on the taper to resist spinning (same with the drive sprocket). With a key fitted, grease or neverseize could be used to facilitate easy removal.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
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Online Triton Thrasher

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Re: Confused Dynamo rebuild
« Reply #3 on: 20.11. 2013 19:13 »
Usually called a keyway, if that's any help.

And Woodruff.

Online trevinoz

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Re: Confused Dynamo rebuild
« Reply #4 on: 20.11. 2013 19:49 »
I wouldn't bother cutting a keyway into the sprocket.
They never slip if tightened properly and the sprocket can mostly be easily removed with the correct methods.
If you look at the dynamo fitted to the Matchless/AJS singles, they use the taper and key and the majority of them come loose and destroy the end of the shaft.

Trev.

P.S.  A lot of the original armatures had a keyway but a key wasn't fitted as the sprockets, to my knowledge, never had keyways.

Offline Marqs1979

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Re: Confused Dynamo rebuild
« Reply #5 on: 20.11. 2013 20:44 »
I have already managed to make a keyway in the sprocket. It will certainly be good I hope  *conf*.

This old machine is very useful :)

http://forumbilder.se/CG4ML/20131120-205814.jpg
http://forumbilder.se/CG4ML/20131120-205828.jpg

Offline A10Boy

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Re: Confused Dynamo rebuild
« Reply #6 on: 20.11. 2013 20:57 »
I agree, there's very little load on this taper and it won't slip if tightened.

Regards

Andy

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Online RichardL

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Re: Confused Dynamo rebuild
« Reply #7 on: 20.11. 2013 22:38 »
I agree, there's very little load on this taper and it won't slip if tightened.

Too late, apparently.

Going to what Muskrat said about "neversieze", that does seem a good idea. It would seem to me that adding the friction of the woodruff key to the "stick-on-there-ness" of the taper would make the job that Trev calls easy even harder for those of us with less than perfect tools (sprocket pullers, that is).

Richard L.
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Online bsa-bill

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Re: Confused Dynamo rebuild
« Reply #8 on: 21.11. 2013 10:16 »
I'm not an engineer (although I have repaired the string on a carrier bag - NE joke)
but it occurs to me that a key and a taper is a combination not so good, if the key is a thou too big (width or depth) it negates the taper, if it's a thou too narrow it negates itself,
having said that I'm sure there are members here who could get it spot on
All the best - Bill
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Offline muskrat

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Re: Confused Dynamo rebuild
« Reply #9 on: 21.11. 2013 12:28 »
But don't throw away the key for the mainshaft/clutch center. *bash*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
Australia
Muskys Plunger A7

Offline A10Boy

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Re: Confused Dynamo rebuild
« Reply #10 on: 21.11. 2013 14:09 »
Maybe too late for Marqs1979, but there's very little load on this taper and it doesnt need a key.
Regards

Andy

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Offline wilko

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Re: Confused Dynamo rebuild
« Reply #11 on: 21.11. 2013 22:05 »
Only matchless and Ajs singles used the key. I've used the A10 type armature on a Matchy without a key and it stayed put for 10 years

Offline Marqs1979

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Re: Confused Dynamo rebuild
« Reply #12 on: 22.11. 2013 14:09 »
When I mounted dynamo I tried it with a power drill. I got it not to generate any electricity. but when I pressed the brushes with my fingers it started to charge. guess it will be better when the brushes have worn to a bit? Now load it without I press them but it charges more if I press.

Is this normal? I think the springs that push the brushes feels good.

Online Triton Thrasher

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Re: Confused Dynamo rebuild
« Reply #13 on: 22.11. 2013 18:26 »
When I mounted dynamo I tried it with a power drill. I got it not to generate any electricity. but when I pressed the brushes with my fingers it started to charge. guess it will be better when the brushes have worn to a bit? Now load it without I press them but it charges more if I press.


Make sure the brushes slide freely. You can get a buildup of greasy stuff inside the rectangular holders.

Offline warmshed

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Re: Confused Dynamo rebuild
« Reply #14 on: 24.11. 2013 23:22 »
Clean the commutator with glass fibre pen then retry. (something like this http://www.ebay.co.uk/itm/HAMA-GLASS-FIBRE-ELECTRICAL-CONTACT-CLEANING-PEN-BATTERY-CONTACT-CLEANER-/200936060889?pt=UK_Camera_Cleaning_Equipment_Kits&hash=item2ec8b8f7d9) The commutators can get glazed. Make sure you have good quality brushes too.