The Dynalite units are based upon original dynamo models therefore to choose the correct Dynalite the original unit needs to be identified. Identifying your existing dynamo is simple, Lucas dynamos are stamped with the model type. (Rust and paint may need to be removed to identify type).. The main point of this article is to provide a simple and easy to follow wiring diagram should you need to repair or rewire your classic motorbike. I am basing this article on the Lucas E3NL dynamo and MCR2 voltage regulator units fitted to my 1951 Matchless G3LS, but the same holds true for the majority of makes and models from the same era.
The wiring diagram above shows the instant when the red coils are on the axis of the magnetic field of the field coils and the green coils (being shorted by the brushes) are perpendicular to the field (which is on the commutation axis).. The Lucas E3H dynamo used in these pictures has two bakelite terminals for connecting the dynamo to the wiring loom. Wire links on the inside of the insulating plate are used to connect these terminals to the workings of the dynamo. The dynamo can then be reassembled, the two field coil wires fitted with ring terminals and connections finalised.