Further Dynamo Problems

[nevhunter]

It's geared up a lot from Magneto speed. Nev

[ian williams]

when i rebuilt my E3L dynamo i found i had to get the revs up before it would "cut in" and produce a good voltage , something like 1100rpm from the engine .

at first it did take a short spell before the brushes made proper contact , you can rub the ends of brushes on some white gloss card to clean them and see how hard they are .
i had to run dynamo for about 30secs with around 1100rpm and then brushes must have bedded in and it started working and has ran fine ever since , it still requires engine speed to go up just above 1000rpm before it all cuts in.
perhaps its just the speed your testing it at that isnt fast enough and youll find it works fine if you spin it faster , i didnt get on with a cordless drill as it wasnt fast enough but found an old "skip find" 230 volt black and decker drill from the 1960/70s worked a treat because it was much faster .

i take it that you scraped out a bit the fibreglass insulation [or whatever it is] between the segments of the comutator with a broken hacksaw blade so to clear any old carbon residue from previous brushes and to give it a small gap so it doesnt short between segments .

hopefully youll have the dynamo sorted without any bother .

cheers , ian