Abstract: A power semiconductor bridge assembly for an alternator-fed DC power source, including positive and negative parallel spaced DC bus bars and a plurality of disk device phase modules disposed therebetween for interconnecting the bus bars with the alternator phase windings. The modules are mounted within the bus bars so as to facilitate their installation and removal. Each phase module includes a pair of disk-type power semiconductor devices separated by an inner heat sink which is connected to a motor phase winding, and sandwiched between first and second outer heat sinks. The semiconductor devices and various heat sinks are aligned along a mutual longitudinal axis which substantially coincides with a longitudinal axis of the bus bar cavity. The outer heat sinks are staggered or offset along a transverse axis of the cavity such that the first outer heat sink engages the positive DC bus bar, and the second outer heat sink engages the negative DC bus bar.