Abstract: A brushless exciter rotor mounting of a sleeveless design directed to a rotor core which is mounted on the shaft of an AC generator so that the rotor core can be rotated by the generator to provide direct current to the generator. The shaft has a stepped construction providing a larger diameter of the shaft at the inner end portion and a lesser diameter portion of the shaft extending outwardly therefrom. The rotor core has a slightly larger inner diameter than the lesser diameter portion of the shaft for a predetermined length to provide a radial clearance therebetween. At the inner end of the shaft the rotor core pilots to the larger diameter end portion of the shaft and at the outer end portion of the shaft a standoff casting pilots to the shaft. The shaft is keyed to the rotor core to prevent rotation of the shaft within the rotor core.