Can anyone help please. I had a dynamo problem on my chummy. It didn't appear to be charging. Sent it off and it was overhauled by ARMOTO. Refitted to car but still no charge. Did usual checks with help from Adam at ARMATO. Joined (bridged) F and D terminals and put volt meter from bridge to earth started engine - no voltage!!
Removed dynamo and clamped in vice. Did the same test, spun it up with a hand drill and got normal output from dynamo. Put it back into car and tried again. No output again. Thought that the dynamo was not being properly earthed so rigged up a cable from the dynamo securing bolts to a good earth but with no effect.
Removed dynamo and ran test once again and sure enough it works perfectly. I have checked that the armature is rotating when dynamo is fitted to the car.
Can anyone shed some light on what may be happening.
Best regards
Martin Nash