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Ruby dynamo problem......???
#1
My Ruby was placed on the naughty step yesterday, just going off to meet with the local A7 club members but just half a mile from home the ignition warning light came on, so immediately about turned and swopped cars.
As the old Sam Cook song goes "Don't know much about .......electrics" but I assumed it must be a dynamo or cut out problem.
Sorted through numerous old articles and forum links and carried out a few tests but could not find any continuity from the dynamo using bulbs and circuit testers and so removed the cover to investigate further and found what looks to my untrained eye a broken wire.
I realise that to some this may be blindingly obvious but for all the Sam Cook's of this world, me in particular, can someone more knowledgeable please confirm that this is the case.
If it's dead I'll need to replace it.
Cheers Denis S


Attached Files
.pdf   Dynamo pic.pdf (Size: 405.41 KB / Downloads: 84)
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#2
Hi Denis
I can’t quite see a loose end from the picture.
But it looks like the third brush lead which connects the brush to one end of a field coil.
Hope this is of some help
Regards
Tim
Ps from the fault described this would fit

After another look if it’s the brown wire which is homeless then it’s either a main brush to earth .
Or the other main brunch to Dynamo output
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#3
Yes it is the brown wire going up at about 90 degrees from just behind the coiled wire and then comes to an abrupt halt and there is a small gap and the wire then appears to carry on up into the dynamo.
Denis S
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#4
Hi Denis

A sudden change from working to not working has all the hallmarks of a wire parting company. Heat, vibration and enough time are the usual cause.
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#5
If it does look like a simple break then it gives you some impetus to take the thing apart and know you are going to get a quick win! Why not put your no.1 cylinder to TDC (you may have a pointer on the cam pulley already - even easier) then you can take off the dynamo and distributor - and know how it will be put back again to keep approx the right timing position.
It looks from under the cover that the dynamo has had some reasonably recent work?
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#6
Jon, no recent work, the dynamo was the original on the car, it was simply tested, cleaned and grooves recut, new brushes etc fitted but nothing much else but this was a long time ago before the restoration stalled so it has only 700 miles of service since the completion. The wire is definitely broken and there is a gap of about. 1/8” I can move the wire.
I do have a spare reconditioned dynamo which I only had reworked by Vince Leek in May this year, must have had a premonition.
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#7
The wire from the top brush (D) passes very close to the armature on it's way to the terminal block and care needs to be taken to make sure there is clearance.
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#8
Dave, does that wire pass out to the D terminal on top of the dynamo?
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#9
Yes Denis.
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#10
Cheers Dave
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