Analysis of Electrochemical Corrosion in Traction Motor’s Bearings Considering Overvoltage and Stray Current in High-Speed Trains

The electrochemical corrosion of traction motor bearings is a critical issue in high-speed rail systems. The over-voltage caused by over-phase and on-board vacuum circuit breaker (VCB) opening and closing of the high-speed train will be spread to the traction motor through the coupling of the car body, bogie frame, etc.,. It makes the shaft end of the traction motor to the motor shell voltage rise significantly for a long time, which will cause serious electrochemical corrosion of motor bearings. In this paper, the mechanism of the electrochemical corrosion of traction motor bearings is studied. It is of great engineering significance to reduce the risk of bearing corrosion and improve the operating environment of traction motors. The principle is analyzed, and the overvoltage corrosion model of the traction motor bearing during train phase separation is established. The simulation data and the measured data are verified to show the model's reliability. It found that the change of train protective grounding mode has a great effect on the operating overvoltage propagating to the motor shaft. The findings provide insights into the damage mechanisms and influencing factors, contributing to the development of effective suppression techniques to extend the reliability and lifespan of bearings in high-speed train applications.