MFPT Bearing Envelope Analysis.pdfVIP

A QUICK INTRODUCTION TO BEARING ENVELOPE ANALYSIS Eric Bechhoefer Green Power Monitoring Systems Cornwall, VT 05752 Telephone: (802) 377-0160 ebechhoefer@ Abstract : Bearing envelope analysis (BEA) is a powerful technique for the detection of bearing faults. The improper selection of the envelope window frequency and window bandwidth can render the analysis ineffective. This can reduce the ability to perform condition monitoring to correctly identify a degraded bearing. This paper is an analysis of how BEA works in the detection of damage bearings. A description of the BEA is given, methods for window selection, such as spectral kurtosis, is described, and example algorithms are given to facilitate experimentation. Key words: Bearing Analysis, Envelop, Heterodyne, and Condition Monitoring Systems; INTRODUCTION: Rotating equipment in general and equipment such as wind turbines are dependent on a transmission to condition the power for useful work. In the case of wind turbines, the power of a high torque, low speed main rotor shaft is converted into a high speed, low torque generator shaft. Integral to the reliable operation of this transmission, are bearings. Reliability and availability of the wind turbine are improved if monitoring techniques are developed, which can detect when a degrading or fault y bearing requires maintenance . This is the essence of condition monitoring for bearings. Because the vibration signals of a faulty bearing are small compared to shaft order and gear mesh frequency, detection of faults at the bearing rate frequencies using Fourier analysis is difficult. Fault detection