Abstract: A self-excited brushless AC generator as a single or polyphase main winding, a generator field winding, an exciter device for drawing current from the main winding for energizing the generator field winding when the main winding is under no load and normal load conditions and an auxiliary exciter system responsive to the generation of a harmonic of the generator fundamental flux to supply current to the exciter device for energizing the field winding when the main winding is under short circuit conditions. The auxiliary exciter system has an auxiliary winding wound with the main winding so as to be responsive to generation of the harmonic flux and an automatic voltage regulator. The regulator has a first input coupled to the auxiliary winding, a second input coupled to an output of the generator and an output coupled to an exciter field winding which is inductively coupled to an armature winding of the exciter device.