Sopwith wiring diagram - help appreciated

We are hoping to reinstate the lighting/charging circuit on the Sopwith/ABC and looking for an appropirate circuit diagram. It has a 3 brush dynamo; what looks like a charge selector (off,charge,low high) not sure if this contains any cut-out. All help appreciated
thanks
Ian

Not sure if it helps but maybe you can find some info in the ABC Instructions manual: http://www.nationalmotorcyclemuseum.co.uk/product/abc-motorcycle-1920-1924-instruction-manual-published-by-the-sopworth-aviation-and-engineering-co-ltd-edale2842/
I've never seen one but I've been told it's different than the catalogue pictured in the gallery.

Any clues as to who made the dynamo?

Giovanni,
Thanks for the link. The 3 pole dynamo is Lucas; however it may be a replacement
regards
Ian