Dynamo not charging at high revs

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Sidney'61
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Dynamo not charging at high revs

Post by Sidney'61 »

Hi,
Recently I've found that the ignition light in the traveller seems to be coming on whenever at higher revs so when accelerating or cruising over about 35mph and doesnt go off again until I slow right down. The brushes in the dynamo were changed a couple of months ago and worked fine but it was only very recently converted to negative earth, what's the likely problem?
Thanks, Andy
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______

bmcecosse
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Re: Dynamo not charging at high revs

Post by bmcecosse »

Loose fan belt?
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MarkyB
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Re: Dynamo not charging at high revs

Post by MarkyB »

Knackered/wrong fan belt?
The belt should ride in the V of the pulley, not at the base, have a look at it's surface to work out if there is a problem.

"Once you break something you will see how it was put together"
Sidney'61
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Re: Dynamo not charging at high revs

Post by Sidney'61 »

Well I tried to tighten the fan belt and it seems to have made it worse, the light now comes on even earlier. Should I just try changing the belt completely then?
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______

mike.perry
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Re: Dynamo not charging at high revs

Post by mike.perry »

With the engine switched off (Got to say that or some daft bugger will try it with the engine running), grab hold of the fan blades and try turning them.
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Sidney'61
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Re: Dynamo not charging at high revs

Post by Sidney'61 »

The fan turns easily and turns the dynamo with it...
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______

bmcecosse
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Re: Dynamo not charging at high revs

Post by bmcecosse »

Problem is more likely then to be sticking brushes. But a better diagnoses would come with use of an ammeter and a volt meter !
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mike.perry
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Re: Dynamo not charging at high revs

Post by mike.perry »

It should be stiff enough to try to turn the crankshaft
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Sidney'61
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Re: Dynamo not charging at high revs

Post by Sidney'61 »

Changing the fan belt made no difference, looks like the new brushes didnt last long then! I'll look into it. Though would it definitely be nothing to do with converting to negative earth last week?
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______

bmcecosse
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Re: Dynamo not charging at high revs

Post by bmcecosse »

Well - as long as you repolarised it correctly ?
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