Monitoring Oil Levels Of Journal Bearings Based On The Analysis Of Vibration Signals

This paper presents a study of monitoring the oil starvation of a journal bearing based on vibration analysis. A diagnostic model is established by includ-ing asperity ploughs and collisions. These excitations are more significant as the oil level is reduced due to less oil film effect. However, it has been found by modulation signal bispectrum analysis that the instable oil whirls can affect the measured responses in the middle frequency range (3.5kHz to 5.5kHz), leading to a good detection of the instability but an inconsistent diagnosis. However, the structural resonances in the high frequency range (5.5kHz to 11kHz) can better reflect the excitations and result in a more agreeable separation of different levels under wide operating conditions.