In-situ balance of an Open Cycle Gas Turbine
A vibration problem arose at an Open Cycle Gas Turbine. Following an outage on the four gas turbines and two SSS[1] clutches, the machine returned to service with unacceptable vibration…
A Simple Step-by-step Guide To Bearing Vibration Analysis
Generally. when developing and testing bearings a simple step by step procedure should be followed.
Vibration Monitoring Phase Measurement And The Tacho Signal
Any vibration signal may be analyzed into amplitude and phase as a function of frequency. The phase represents fifty percent of the information so it is most important to measure phase for vibration monitoring. Most vibrations on a rotating machine are related to the rotational speed so it is clearly important to have a measure of the speed, either directly or as a once per revolution tacho pulse. A question sometimes arises as to whether a once per revolution tacho reference signal is needed to measure phase. Is it possible to get phase if we only have a speed signal? This note gives some insight into those questions.
Actually the question that should be asked is – “Can we measure a meaningful phase, for use in vibration monitoring, if we only have a speed signal as well as the vibration signals?”
