A winding of an electric machine is provided, where the winding includes at least one series of serially connected AC bars. Each AC bar includes a series of serially connected turns formed by litz wire having a plurality of strands, and at least one cooling tube. Individual strands of the plurality of strands are respectively positioned substantially adjacent to the at least one cooling tube at at least one transfer point for providing heat transfer from the respective individual strands to the at least one cooling tube.