In huge rotating equipment such as turbines, which type of sensors preferred to measure vibration at high speeds ?

On-line vibration and dynamic condition monitoring

Vibration monitoring is the core of dynamic control for the main rotating machinery. It is the primary on-line, real-time source of diagnostic information on the actual dynamic condition of the machine (Doebling et al., 1996). This information is integrated by other parameters, ranging from current unit load to oil-film pressure, to help the diagnostic interpretation of vibration data. Nowadays vibration monitoring systems of high complexity and performance are able to deliver exhaustive, real-time diagnostic information to the power plant staff on the actual dynamic condition and performance of rotating machines.

Standard high-performance vibration monitoring systems consist of pairs of accelerometers mounted on each bearing of the turbine shaft, at 908 from each other (see Fig. 2.8). An additional sensor (‘key phasor’) is also required to provide a common time reference for a correlated analysis of signals from the different sensors. The system necessarily includes on-site signal conditioning modules as well as a data acquisition and processing subsystem. Such a system can provide a real-time frequency analysis of turbine vibration and in principle enables a relatively sophisticated diagnostic appraisal of the machine dynamic condition.