METHOD AND APPARATUS FOR COOLING A ROTOR ASSEMBLY

A method of cooling rotor winding end turns extending from a rotor core includes coupling a collar to a rotatable shaft of the rotor core. The collar has a first wall confronting the rotor core, a second wall spaced from and opposing the first wall, a third wall between the first and second walls defining a set of apertures therethrough, a first cavity cooperatively defined by the first, second and third walls, having a first opening opposing the third wall, a fourth wall circumscribing the third wall, a second cavity cooperatively defined by the second, third and fourth walls, the second cavity defining a second opening opposing the second wall. The first and second cavities are in fluid communication, and the rotor winding end turns are receivable into the second cavity. The method includes directing a coolant into the first cavity, and delivering the coolant to the second cavity.