Exploring Electrical Metrics for Tribology Measures in Oil Films: System Design, Analysis Principle and Physical Effects

This study investigates lubricating performances of oils through altering the working conditions in accelerated aging tests, observing the degradations on the lubricants’ performances and incorporating in-time detections for verification. To meet the aims, a new measuring system has been developed to observe alterations of the recorded viscosity index, color difference, thermal coefficient and torque transmission in the oil film under electrical discharges. To resolve the quality of lubricating oil in real time, the discharging waveforms and the acoustic indexes were applied to the marginal Hilbert spectrum for characterizing the time-frequency domain features. The Fisher score of the selected features successfully differentiated the new and used lubricants. The physical effects in association with the degradations of oil films are reported in detail.