I've re-built the engine and put it back in the chassis. I'd like to run it to check every thing's OK while I wait for the body to be painted, but been told it doesn't do 3-brush dynamos any good to run them disconnected.

Any advice welcome.

'35 AAK

If the output and field terminals are connected together but to nothing else a high voltage may eventually overheat the field windings. (Performed briefly it is a test for a working dynamo) But with either or both terminals connected to nothing else, not a problem.

(On early DEL dynamos where an internal connection may exist the output terminal can be firmly earthed. It seems contrary to electrical practice, but the dynamo cannot then develop any volts to keep itself going.)

Location: Auckland, NZ