Influence of surface roughness on ball bearing electrical capacitance under elastohydrodynamic lubrication

Hamid Ghorbani

Summary

The electrical capacitance of bearings is a critical parameter for evaluating harmful bearing currents, which can lead to premature failure of both the bearing and the entire drive system. While empirical formulas for assessing the influence of rolling speed, load, temperature and material properties on capacitance are well established, the effect of surface roughness under elastohydrodynamic lubrication (EHL) has received less attention. In this study, the impact of surface roughness on bearing capacitance is investigated using a numerical EHL model, the results are validated against experimental capacitance measurements. The model is further employed to derive an equivalent bearing capacitance representation across varying load, speed, temperature, and roughness conditions using an interpolation-based approach.