Bearing Voltage Generation and Analysis of Factors Influencing Bearing Electro-Erosion

Bearing currents can cause electro-erosion damage, reducing motor reliability, yet the underlying damage mechanisms remain insufficiently understood. Conventional motor test platforms struggle to accurately detect bearing currents and cannot perform accelerated electro-erosion testing. To address these limitations, this study designs a novel bearing voltage generation and an integrated electro-erosion test platform, enabling controlled damage experiments and laying a foundation for lifetime evaluation under electro-erosion stress. The paper first explains the generation mechanisms of bearing voltage and typical damaging currents, such as electric discharge machining (EDM) currents and high-frequency circulating currents. It then introduces the circuit topology and working principles of the device, detailing how electrical and mechanical stresses are applied. Experimental validation of the circuit and hardware platform is conducted. Further, electro-erosion tests using oil-lubricated bearings are carried out, focusing on the effects of speed, oil temperature, and lubrication flow rate on EDM and circulating currents. Results show that EDM currents are highly sensitive to operating conditions, particularly oil film stability influenced by speed and temperature. In contrast, high-frequency circulating currents are mainly determined by electrical parameters such as voltage spike amplitude and switching frequency, and are less affected by changes in bearing operating conditions. This work provides new insight into current-induced bearing damage and supports accelerated reliability testing.