Abstract: An alternator adapted for use with a motor vehicle includes rotor assembly and a stator assembly, which may be like the rotor and state assemblies of brush-type alternators, and also a contact assembly that includes two relatively low-friction, electrically conductive, ball bearing assemblies that are adapted to conduct the DC exciting current for the alternator and that are electrically isolated from each other. Each ball bearing assemblies include inner and outer races that are electrically connected to each other by a plurality of bearing balls and by electrically conductive grease which is packed about the balls. The inner race of each ball bearing is rotatably secured to the rotary shaft of the rotor assembly and is connected to electrical leads which, in turn, are connected with the rotor assembly. The outer race of each ball bearing is fixed relative to the rotary shaft and is connected with a storage battery.