dynamo

[broom34]

Hi
    Anyone out there that can help me please, I'm having trouble with the dynamo on my A10,it's not charging therefor I'd like to test the dynamo and locate the problem ,now I'm not electrically minded so could someone please explain to me in plane English how to test a dynamo.


Richard

[a10 gf]

(Do a serch in the forum, lots of dyn posts)

Is it known to produce no output?

I guess the drive chain and pinions are checked & ok.
If the dyn has not yet been tested in any way:

To check voltage output while mounted on engine connect a lamp between the shorted two dynamo output cables and the frame and start the bike. Use a 12v lamp due to the unregulated output. The lamp should light up brightly right over idling speed and give more or less light according to engine speed.

& see f.ex. lamp test.

Got voltage output? then the fault is elsewhere (regulator, cabling, ammeter, connections, go trough the system using the schematics. Evaluate to dismantle the dyn anyway for a check\clean.

No voltage? not that many parts in there. Fault in connection\cabling\brush holder, internal wiring, brushes worn or stuck, field coil, armature windings or commutator (I've seen well used armatures with wires torn loose from commutator, needed resoldering). You may need the dyn schematics and a basic multimeter to pinpoint the culprit in there if a visual does not show the error.

Lucas e3l service sheet. More dynamo stuff here.

e

[BSA_54A10]

Most problems with the dynamo are usually in the regulator not the dyno which are notoriously reliable.

Pull the cover off the regulator , get some 1500 wet & dry, soak it in WD 40 . fold a thin strip double ,then do a couple of passes through the 3 sets of points applying light pressure to the points with your finger.

Then flood the points with some more WD 40 to clean off the crud and give the bike a run. 9 times out of 10 this will fix most troublesome Dynos.

Before you do the above take the end cover off your dyno and pull out the 2 carbon brushes. If they are 1/4" or less it is time to change them.
While they are out soak come cotton buds in WD 40 and clean the communator .
If you have compressed air on hand a good blow out would also be a good idea.

[trevinoz]

Trevor,  there are only two sets of points and you are correct in saying most problems are regulator based.
The left hand set tends to get a film of corrosion between them if not used for some time. They appear to be tungsten. The cut out set don't suffer as much and are silver or an alloy of same.
Saying problems are regulator based extends to the ham fisted owners who fiddle with the settings and end up with no regulation and boiled batteries and cooked generator.
Trev.

[broom34]

Hi
    I would like to thank you all for your time and suggestions plus the various sites to visit, I've had some very interesting results,as you say there's lots of jargon about the dynamo,when you start looking, once again thank you all


Richard