Abstract: This invention relates to a stator winding cooler for a generator having a stator, a fluid-filled rotor mounted for rotation relative thereto and a fluid supply delivering fluid to within the rotor. The stator winding cooler comprises a fluid sprayer disposed within the rotor for accepting fluid within the rotor and delivering the fluid to windings on the stator to cool the windings, the fluid sprayer having a variable orifice therein to render rates of fluid flow through the fluid sprayer insensitive to variations in rotor speed. The stator winding cooler is so designed to function in conjunction with the generator which operates at variable speed. The rate of fluid flow through the fluid sprayer is desired to be held constant to avoid over-spraying end windings at high generator speeds. In the preferred embodiment of the invention, oil, which is used as the cooling fluid, is also passed through a fixed metering orifice within the fluid sprayer which provides a maximum flow rate therethrough.