Experimental study of oil cooling systems for electric motors

The present study focuses on the use of lubricating oil as a coolant for electrical motors. Oil is introduced at each side of a 40 kW test machine to directly cool the stator coil end-windings. An experimental setup has been implemented to test different oil injection patterns. The influence of the oil flow rate, rotation speed and oil temperature has been investigated (40 L/h <Qv < 360 L/h, 50 °C < Toil < 75 °C, 0 < ω < 4600 rpm). The results show a strong dependence of the flow rate on global cooling performance, whereas the effect of rotation speed is smaller but can affect local temperature.