Author Topic: A10 dynamo rebuilders  (Read 1213 times)

Offline nagrod

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A10 dynamo rebuilders
« on: 30.08. 2012 20:28 »
I've had the A10 SR running nicely all summer, chasing some of the bugs out, even got a nice set of indicators mounted and working. Before I installed the indicators I started having a charging problem, I ride with the headlamp on and the ammeter would go from showing a charge for a while to full discharge. Now it is on full discharge all the time. I just finished running the dynamo test, bridging F and D and reading voltage between the bridge and ground. The results were disappointing, getting about .7 volts DC at tickover to 1.9 volts DC at about 2000 RPM. From what I have read on this forum that is pointing to a bad armature. The brushes and commutator look good and the bridge wire had good contact in the dynamo female connections. I am not through playing with it but I tried contacting Bell Engineering who rebuilt it back in 97 (Very few miles on it but lots of years) and their web site and phone are out of service. I live in the Northeast US, can anyone recommend a company that services these things? It's on a 1960 A10 Super Rocket.


Rick D
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Offline morris

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Re: A10 dynamo rebuilders
« Reply #1 on: 30.08. 2012 22:46 »
Seems exactly what happened to my dynamo. When testing F+D together I only had 0.2v. On mine the field coil was knackered. When taking it apart, I found the windings short-circuiting all over the place. In this case no magnetic field is generated, so there won't be any power generated.
Worth testing if you got some resistance on your field coil. The book says you should at least measure 2.8 ohms for a 60 watts dynamo.
Field coils and armatures for a Lucas E3 can be bought off the shelf, are not so expensive, and are easy to replace, although you need some special tools to replace the field coil. (I made up my own pole expander, and to tighten the screws I used my pillar drill, and a sawed off screwdriver on which I welded on a nut, put the screwdriver in the drill chuck, pushed down, and tightened them with a spanner on the nut.
Dynamo and alternator rebuilders can be found anywhere, and should be able to help you out if they're serious.

Good luck,

'58 BSA A 10 SA
'52 BSA A 10 Plunger
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Online RichardL

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Re: A10 dynamo rebuilders
« Reply #2 on: 30.08. 2012 23:03 »

The name is Patrick and I'm new here. I've been lurking for a while and enjoying the conversations and tech talk, so, I thought I'd finally join up. This dynamo topic interested me, so, seemed as good a place as any to jump in. Once I get the hang of it, I'll post some pictures of my bike in various states of assembly. Looking forward to many spirited A10 chats.



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Offline muskrat

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Re: A10 dynamo rebuilders
« Reply #3 on: 31.08. 2012 09:48 »
 Is Richard trying to disguise himself or has the gremlins got his avatar/stats mixed up with Patrick. If so welcome Patrick.
A full rebuild kit for the E3L is only about $150 AU, and even I can do it.
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Offline iansoady

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Re: A10 dynamo rebuilders
« Reply #4 on: 31.08. 2012 11:03 »
I had a very similar problem with my E3L dynamo. I also found that if I connected a battery across the field whilst spinning it I got a good voltage at the D terminal.

To cut a long story short, I took it to Paul Cooper in Halesowen, West Midlands (+44121 559 2405) who rebuilt it with new brushes and bearings, cleaned up the commutator and prettied it up then tested it out (now working perfectly) - all for the princely sum of £30.

Excellent quick service and very nice chap (as well as having some gorgeous bikes).

Although you may be on the wrong side of the world for him....

TBH although dynamos are simple machines there are a lot of people purporting to fix them who don't have a clue.
1962 Golden Flash (arrived)
1955 Velo Viper/Venom (departed)
2004 Triumph Tiger 955i (staying)