Non-charging dynamo

[MarkOgden]

Chaps

Following instructions and thanks all, I (ahem!) flashed my non-charging dynamo on the VB600. Seems it is a Lucas E3L from the stamp on the drive end. Sadly this was unsuccessful despite repeated flashes. I have dismantled the non-drive end somewhat, cleaned up the commutator some more, pulled the brushes, and checked the wiring as much as possible. All looks reasonably OK. Some thoughts perhaps...

I noted quite a bit of copper swarf/dust around the brush holders - see pics. Not sure if that is normal. It may suggests that the brush holder or something is picking up on the commutator. I cannot see anything obvious.

I'll check if the brushes slide in the holders and actually touch the commutator. The wear pattern suggests they do though.

Anything else I should look out for, or anything obviously amiss in the photos perhaps? It charged fine before it was laid up!

Many thanks again

Mark.

[will_curry]

That doesn't look right at all. Those brush holders are much closer to the
com than the holders on the dynamo I've just looked at. It looks as though something
has been scouring the com as well.

All being well I'll take some photos either this evening or tomorrow.

[JohnnyBeckett]

hi the brush holders have made a right mess of the commutator like Will says and worn it right down to the undercuts it needs turning down and re undercut or buy a new armature and see why the brush holders are rubbing and fix them you can get all the parts you need or a new recon dynamo non exchange cheap like i did at the kempton park autojumble most recons are exchange but i was kempton and see this seller and got one outright and he made a good job of reconditioning them i hope to buy another two off hin at the next kempton

[alan.moore]

Mark
As has been said the brush holders do appear to be grinding away at the commuter, which should have a smooth surface like the section which has not been damaged.

I think you have the wrong brush back plate fitted, Yours appears to have been modified to 'fit'. If you compare it with the image of a E3L plate below:

On yours you can see where the fibre back plate has been cut/sawn away 'square' above the aluminum bearing support casting to clear it (normally its a 'manufactured curve at that location) and the brush holders appear to have been filed with a radius to clear the commuter. On the one in the image above you can see the shape of the back plate and the inner end of the brush holders are square. The inner ends of the brush holders should sit a lot further away from the commuter than yours do when fitted, about 1/16" .

Its possible that they were originally 'just' missing the commuter and that something has moved and/or the commuter end bearing now has excessive play.

Cheers
Alan

[MarkOgden]

I do agree that the brush holders do not look good and the copper residue is instructive. Alan's note seems to confirm things - many thanks for that, and no I am not guilty!

However, it did charge when laid up - now it doesn't. I cleaned the commutator up well with petrol, gave it a polish with wet and dry, checked the brushes to see if they slide, bridged the D and F terminals and connected a 12V lamp between them and earth (+ve). Nothing. Multi meter read nothing either.

So - where to go from here? I wonder if it is worth obtaining the correct backplate or have I damaged the commutator too much? May be worth a try? - thoughts welcome.
Failing that - I guess I'll pull it off the bike, take a better look, and if I cannot see anything obvious, then exchange it for a good one.

Couple of Qs

How to pull the dynamo off please? Is it simply off with the strap and tug? I forget now....
Any recommendations as to who can exchange or fix the dynamo, which incidentally is a E3LM-LO

[will_curry]

I agree with Alan.

To remove the dynamo slacken off the clamping strap and remove the nut from the spindle which
comes out of the drive end of the dynamo and secures it to the magneto part.

It's not easy to see just what state the com and armature are in but there are some simple tests
which may be useful. Firstly, none of the copper segments of the com should make electrical
contact with the body of the armature. Secondly, each segment of the com should be electrically
connected to all the other segments.

As to where to go for a replacement armature . . .

[alan.moore]

Mark,
You really need to take it to bits so you can have a good look at the commutator. I think it will probably need machining in a lathe to get it back to a serviceable condition. You could try 'restoring' it with a strip of fine glass paper wrapped around it (don't use emery or wet and dry as the particles can get imbedded in the copper). If it is not smooth and concentric with the spindle it will wear the brushes away in short order. You will also need to undercut the insulation between the copper segments.

I would suggest having a read through the Lucas dynamo paper in the websites documents area: http://www.arielownersmcc.com/members ... LM_E3N.pdf

Regarding getting a recon done done have no experience of any of the services offered by the firms found on a google search....I am sure someone on here will have some knowledge of who could do it.

Cheers
Alan

[MarkOgden]

Alan/Will

Many thanks again. My proposed plan of action is as follows

Replace backplate with the proper version - your picture from Fecked would seem to suffice - at 8 quid or so, it is worth a shot.
Clean up commutator further, polish with glass paper as you state, and undercut the insulation - not sure how to do that - advice welcome.
I'll do all the tests Will mentioned.

If it still does not charge, then I think it will have to go away for repair/recon.

Many thanks

Mark

[JohnnyBeckett]

hi if you are going to do the undercut by hand use a hacksaw blade

[fpassmore]

Hacksaw blade is quick to use and a Dremel with diamond blade works well too. Again no emery or sand paper disc as these embed in the com.
Frank