The Influence of Various Grease Compositions and Silver Nanoparticle Additives on Electrically Induced Rolling-element Bearing Damage

Abstract

Abstract Electrified mechanical contacts and electrical connectors are an integral part of electric vehicles, and their reliable performance is essential. This has become increasingly important for electric vehicles where leakage current could potentially load the motor bearings and many other contacts in the drive system. Such leakage current has been shown to rapidly accelerate surface degradation via small scale arcing across lubricating films. Recent work suggests that metallic nanoparticle additives in lubricants may be useful to improve the performance of these contacts. Presented in this report are results from a study on Ag nanoparticle enhanced polyurea greases under electro-tribological loads. Greases with mineral and synthetic base oils with and without additives were also tested for comparison purposes. The results indicate a reduction in pitting from arcing in the presence of nanoparticles, although oils with other additives also appear to exhibit an enhanced performance.