Dynamo Woes

Max Autobrake · Post by **Max Autobrake** » Sun Oct 09, 2011 10:34 pm

I was enjoying an e-mail recently full of 'Lucas Prince of Darkness' jokes. I must have laughed too loudly as it seems my bloody dynamo has packed up!

I had adjusted the cut-out on the regulator and all was working well (for over 500mls) and within the feeble parameters offered by the charging system. Anyway, the voltmeter gave a sudden twitch last week-end and now no longer shows a charge, only a discharge.

My multi-meter shows nothing higher than 1.7v coming out of the dynamo, so I assume it's at fault. I haven't dismantled it yet apart from removing the end-cap, the brushes appear to be good.

Is there anything else I should look at before removing the dynamo? Is it worth pulling the thing apart or best left for a specialist to re-condition (I am mechanically competant but know little about electrics)?

Finally, any recommendations as to where to send it for overhaul?

Many thanks for any advice..........

Max

SPRIDDLER · Post by **SPRIDDLER** » Sun Oct 09, 2011 11:43 pm

Try this:

http://www.matchlessclueless.com/how-to ... -dynamo/5/

Provided that you record details and internal connections as you go (preferably by photograph) and you can identify the fault, a dynamo overhaul doesn't require any electrical knowledge at all.
Removing the field coils (only necessary if faulty) can be a bit of a struggle.Edited by - SPRIDDLER on 09 Oct 2011 10:45:44 PM

wilko · Post by **wilko** » Mon Oct 10, 2011 1:00 am

If you overadjusted the voltage output then you have probably thrown the solder out of the commutator. Take it out and you will see evidence.

en7jos · Post by **en7jos** » Mon Oct 10, 2011 3:30 am

Hi Max,

You're testing the dynamo output with the F and D terminals connected together, with the multimeter connected between them and earth, right? If it's only 1.7v then you're dynamo is almost certainly at fault.

There are some suggestions for dynamo specialists in the 'Recomendations' section of the forum, in particular this thread:

Dynamos and magnetos

My mag and dynamo are currently with Tony. His knowledge speaking to him on the phone sounded extensive and the quoted price reasonable. I'll report more when they're safely back on the bike!

Max Autobrake · Post by **Max Autobrake** » Sat Oct 22, 2011 6:53 pm

Many thanks for the input chaps.