Liquid cooled stator for high efficiency machine

A rotary electric machine includes a stator having a circumferentially spaced series of axially extending teeth defining winding slots therebetween. Stator windings are at least partially disposed in each winding slot and electrically connected to form a plurality of phases. One or more slots contain the same magnitude of current at substantially all times for each phase. Structure defines a plurality of elongated coolant passageways disposed in each winding slot. A subset of the coolant passageways contained in the slots for a single phase is an even number. Fluid flows in one direction for half of the subset of coolant passageways and in the opposite direction for the other half of the subset of coolant passageways. At least two of the coolant passageways in the machine are fluidly connected in parallel. At least one of the coolant passageways is located circumferentially between two windings in the same slot.