Liquid internal cooling of electric machine windings in arctic conditions

Direct water cooling has been used only in large size turbo generators. The method might, however, offer interesting possibilities also in high torque applications. The performance of different cooling fluids for internal liquid cooling of windings is assessed. The arctic operating conditions of machine place special requirements for the fluid thus pure water can not be used for cooling. It is found that use of the anti-freezing substances studied decrease the performance of the cooling system. Fast computational model to asses these effects is proposed.