Stator Winding Temperature Rise Testing for Medium and Large Polyphase Induction Motors Investigated

Motor stator winding temperature rise limits and test requirements are established by industry standards, customer specifications or the materials used in the insulation system. NEMA, IEC, and CSA standards describe how stator winding temperature rise is measured based on certain criteria, such as the rating or frame size of the motor. This paper details the differences in these standards and how the tested motor temperature rise varies depending on the standard being used. The value of temperature rise measured by embedded detectors placed in the stator slot is investigated and compared to the results from thermal stabilization tests where the temperature is determined from a rise by resistance calculation. Test data for Medium and Large motors is provided.