The brushless excitation and conventional DC excitation systems are comparable but one significant change is _______
(a) pilot exciter is brushless permanent magnet motor
(b) three phase rectifier feeds directly to main exciter
(c) a three phase rectifier is fed by main exciter
(d) no direct rectification is provided to the pilot exciter
This question was addressed to me by my college director while I was bunking the class.
Asked question is from Excitation Systems for Synchronous Machines topic in section Synchronous Machines of Electrical Machines