Rolling Element Bearing Analysis

All rotating machinery uses bearings to support the load and maintain the clearances between stationary and rotating machinery elements. More than 90% of these machines have rolling element bearings. Unfortunately, rolling element bearings are prone to a myriad of premature failures. A mere 10% of rolling element bearings reach their L10 life, the expected life of 90% of similar bearings under similar operating conditions. Early failures are attributed to lubrication, load and design/application errors, and even pre-existing problems that were not detected during manufac ture. A comprehensive condition-based mainte nance program incorporating preventative maintenance and predictive maintenance should be in place to detect the onset of wear and deterio ration of rolling element bearings. A mature program provides not only indications of wear in the bearings, but also an evaluation of the severity and recommendations for when corrective actions should be taken. The purpose of this paper is to briefly discuss how the high-frequency natural bearing resonance indicator, discrete frequency indicators (acceleration), acceleration timewaveform characteristics, acceleration timewaveform crest factor, and the velocity amplitude of bearing fault frequencies associated with rolling element bearings can be integrated to determine bearing health and the risk of catastrophic failure.