Voltage is ONLY "tool" to handle all currents there in system !!!!! Rotor is very "stupid", cause more AC Voltage/power/CURRENT is coming from it with more RPMs. Ducati rotor gives about 70-80 AC Voltage output with high RPMs and surely battery(from what circuits are connected to)is boiling with high RPMs, if regulator cant lead one part of that rotor current DIRECT TO EARTH !!! Thats why sometimes regualator faults are caused by BAD regulator EARTHING.... Regulator MUST be very well earthed allways caused by this current feed to earth.... Regulator dont send any "excess voltage to eart" but excess current !!!! Voltage is only "tool".... Btw, i have been electrician now about 30 years..... I have learnd something about it alreday....
907IE rotor gives maximun 350 Watt output, newer ST modells much more. Remembering, that 750 Paso gives 300W.
PS. regulator are normally "adjusted so"(with components), that if battery voltage try to go too high(about more, than 14.6 Volts), then it start to lead CURRENT more direct to earth AND not boil battery. Regulator can "read" only voltage and then it handles currents to earth and to battery(read loads)...