[Lynn Eades]

David, the P is connected to the Field terminal and the B to the armature (big wire) via the cut out.
I don't know my way around the three brush geny with the cut out, and how the cut out is wired up, but yes the field needs feeding to make it charge. good earths are also important.
Power comes from the battery to make the ignition warning light go and power comes from the generator to put the light out when its charging. (opposing voltage neutralises the electron flow= light out