The E3LM dynamo on my 1950 VB is not charging. I have video evidence that it was charging before it was shipped from the U.K. to me here in N.Z..
The bike is positive earth; the resistance between the dynamo body and a frame bolt is 0.2 Ohms, which is the same as I get when I short the leads of my multimeter together, so i think the earthing is o.k..
I have followed troubleshooting guidance given on the "matchless clueless" website and have made the following measurements:
- Field terminal to earth resistance = 3 Ohms; Dynamo terminal to earth resistance = 4.3 Ohms
- With the F and D terminals shorted together and the engine idling, I measure around 0.2 V between the terminals and earth, which doesn't seem to change much if I increase the engine speed a bit.
- I have tried flashing the field coil, but no change in voltage readings.
- I have removed the brushes and lightly cleaned the commutator (it wasn't particularly dirty). To my inexperienced eye, the brushes and commutator appear o.k.
A Lucas manual
I downloaded seems to suggest the trouble is with the field winding, but the resistance I have measured is the same as that on my Panther's E3LM dynamo, and it works perfectly.
I'm not sure what the next troubleshooting step should be.
Any guidance would be much appreciated.