TRANSIENT SPEED VIBRATION ANALYSIS - INSIGHTS INTO MACHINERY BEHAVIOR

摘要

This paper discusses the methodology & benefits of analyzing machinery vibration data taken during start up and shut down. This 'transient speed' data provides exceptional insight into rotor dynamics. It allows us to better understand and accurately sort out those machinery problems that are not readily solvable when using only steady state/spectral analysis, as is commonly done as part of 'Predictive Maintenance' or PdM programs. We will review the equipment and techniques used to acquire vibration data during start up and shut down. We discuss how to properly set up for and sample transient data, and offer guidelines on selecting the correct vibration transducers based on machine type. Guidelines for vibration analyzer configuration are provided. We review transient data plot types used in analysis, including: polar, bode, waterfall, cascade, orbit/time-base, and shaft centerline. We also discuss how to identify the major classes of machine faults using transient data: mass unbalance, shaft misalignment, rotor resonances, structural resonances, shaft centerline movement, rotor to seal rubbing, and oil whirl/whip.