A compact, high power, power conversion apparatus including a rotor and a stator. The rotor includes a cylindrical casing, and a predetermined number of permanent magnets disposed on the casing, and is adapted for rotation about the axis of the casing. The stator includes a core and a plurality of sets of conductive windings, each set including a predetermined number of individual conductive windings and associated with an electrical phase. A respective collecting conductor is associated with each set of conductive windings, with each individual conductive winding of the set being electrically connected to the associated collecting conductor. The respective collecting conductors are disposed in a coolant flow path a coolant flow path directing coolant into contact with the stator windings, electrically isolated from each other and spaced apart from each other and from the windings. Collecting conductors in the form of continuous rings and in the form of a plurality of arcs are disclosed.