A.R. Gatlewar , D. R. Zanwar , G. D. Mehta , J. P. Modak

Abstract

This paper describes the vibration based monitoring and analysis techniques to detect defects and to diagnose fault of bearings for thermal power plant 210 MW units. Tri-axial vibration measurements were taken at each end of the coupling on the shaft and rotor bearing housings. The result shows that bad bearing has a strong effect on the vibration spectra. Vibration spectrum analysis has been employed to identify different defects in bearings. The results have demonstrated that this technique is useful to detect problems in bearings. As a general rule, machines don’t trip or fail without giving some form of warning, which is indicated by an increased vibration level. By measuring and analyzing the machine’s Vibration, then it is possible to determine both the nature and severity of the defect, and hence predict the machine's failure. In the present work the effect of load on turbine, working under 3000RPM speed at seven loading conditions are studied. For this reason, Detection, location and analysis of faults of turbine bearing are studied & corresponding Fast Fourier Transform (FFT) spectrum has been recorded for each case study. Various faults are also discussed in this paper. Results of some faulty bearing are shown that the vibration amplitude affected by changing both load and/or speed, therefore, it is important to fix the measuring positions as well as speed and load as much as possible to implement a good maintenance vibration monitoring program.

Keywords- Vibration Signatures, Vibration Spectrum Analysis, Detection, Location and Analysis of Faults.