way past ee101.
if you keep the stator grounded ac then the frame voltage out of the rectifier is not zero or ground. the + rectifier terminal is 7.6v and the - terminal is -7.6v. if you run with ground at -7.6v you are floating ground.
the frame is ground if you reassign ground to the rectifier. that is done by ungrounding the ac stator and running 2 phase. by changing the ground point and grounding the rectifier the frame now becomes 0 and the rectifier + terminal is 14.3vdc. perfect for running a tiny gel battery or led's and a capacitor. this is a valuable skill. its the path for antique to modern 6v to 12v conversions. you are actually showing a pic of exactly how I run. its a great repair but its solid and does not float. this pic is a 3 phase repair.
honestly I don't care if you don't see what I say. the important thing is we wont get banned for posting. similar pic got me banned from the honda twins website.