Dynamic Investigation of Traction Motor Bearings Considering Rotor Eccentricity in a Locomotive

Rotor eccentricity is a common fault in traction motors that directly affects the stability of the locomotive system. A locomotive-track coupled spatial dynamics model with traction power transmissions was established by considering the effect of rotor eccentricity in this study. The time-varying gear mesh forces, nonlinear wheel-rail contact forces, internal interactions between the components of the motor bearing, and dynamic forces induced by the rotor eccentricity, namely centrifugal force of the rotor, rotor-motor rub-impact force, and unbalanced magnetic pull (UMP), were comprehensively considered in the proposed model. The results indicated that rotor eccentricity affects the vibrations of the traction motor significantly. Additionally, the working condition of motor bearings was deteriorated by the rotor eccentricity, which was reflected by the increase in contact forces between the roller and races. The load region of the non-driving end bearing varies with the angular position of the rotor under the effect of rotor eccentricity. The proposed dynamics model will contribute in understanding and controlling the nonlinear dynamic behavior of locomotive traction motors.