Transient and Non-Steady State Vibration Measurements

摘要

The vast majority of vibration measurements, particularly in periodic monitoring programs, are under steady state conditions. This paper illustrates performing analysis on machines that are either in a mode where speed is changing (sometimes very rapidly) or operating conditions are varying with time. Five case histories are presented which are: A large fan with a bowed rotor that is operating near its critical speed, a 40,000 HP compressor with Morton effect, a compressor undergoing flow surge, a 500-Megawatt turbine that experiences a hard thermally induced rub and finally a large compressor that is exposed to a torsional stimulus as its synchronous motor comes up to speed. These case histories illustrate the challenges and special analysis techniques that are utilized when monitoring non-steady state conditions.