12-10-2021, 11:34 PM
What Dave states is basically true. Neverthelss thrown solder at some stage was/is more or less the norm for Seven dynamos and certainly worth trying. (I have never run a dynamo which has not suffered! Unlike modernd Sevens are not quickly immobilised if generation fails). Usually enough solder remains for electrical connection. The 2 pole armatures are wired 1 to 2 to 3 etc around to 1. There are therfore two parallel paths between adjacent comm segments, one longer than the other. Prior to digital meters it was a bit of a fiddle to check. But digital meters read very low ohms and the resistance between adjacent bars (without brushes) should be very comparable. Poor connections show and can often be restored by resoldering those bars (taking care not to get flux in the winding), or all.