A Study on the Estimation of Bearing Life of Electric Motor Using ISO 281 and Accelerated Life Test

This paper introduces the results of the study on the development of accelerated life test methods for the motor used in machine tools. In recent years, as well as efficiency for motors, there is a growing need for research on life expectancy of motors. It is considered impossible to calculate the acceleration coefficient by increasing the rotational load or temperature load as the acceleration stress in the motor system because the temperature of the copper exceeds the wire thermal class rating. In general, the failure of bearings in a motor accounts for most of the total failure factor. This paper describes the development of the procedure for the lifetime estimation of the 12 kW three-phase squirrel-cage induction motor. The test to predict bearing life was conducted and the result was compared with the bearing life expectancy by ISO 281. Finally, a lifetime correction coefficient was calculated.