Dynamo

[Jack in the Box]

I've never had to reverse the field connections, however any dynamo which doesn't cooperate is stripped examined repaired and rebuilt correctly. I've lost track of which dynamo you have, are you certain all the connections are correct? With no undesirable shorts or earths, the early C35 dynamo brushgear has insulating bushes which after 80 years usually disintegrate see photo. With new field coils and rewound armature there isn't much else apart from incorrect wiring or shorts to cause your problem.

Dave,
In your diagram, would you happen to know the value of the resistance between the D and F terminals please?
Thanks
Alan