On the electric behaviour of conductive grease inside the contact zone

Conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings. Understanding the conductive grease performance, especially the electric and tribological behaviour is crucial for its application. This paper combines bulk grease characterization and contact film study considering both electrical and tribological loading conditions. The results show that the electric performance for the selected conductive grease sample is electric field dependent, including both frequency and voltage amplitude. Its film impedance inside the contact area is closely related to the external electric field, running condition, and lubrication regime. The following film impedance calculation tells that not only bulk grease electric parameters, but the contact parameter, lubricant film contour and lubrication condition should be considered when performing the overall bearing electrical modelling.