[ARC5] Ideas on Japanese circuit ?

[Hubert Miller]

To be more clear, why does it seem that the keying relay and microphone current are taken from 
a dynamotor field, and not the 6 volts main power? It looks like this one separate field of the rec
dynamotor only runs the pilot lamp and the keying relay and mic ! The schematic does not show
how the filaments get their power, but it would have to be from the 6 volt battery main, not the
dynamotor; that would make even less sense and be very inefficient. I do not have either 
dynamotor anyway, so i can workaround this "separate DC circuit".
-Hue Miller