Motohiro Shiga

Vibration diagnosis method and apparatus for rotary machines

A vibration diagnosis method and apparatus for rotary machines adapted for measuring the vibration of rotor shaft of a rotary machine, extracting the vibration component synchronous with the revolution of the rotor shaft from the measured vibration data, comparing the amplitude of the extracted vibration component with the amplitude of the overall vibration, analyzing the causes of the synchronous vibration component when the result of the comparison meets a predetermined reference, judging, in accordance with the result of the analysis, whether the vibration due to mass unbalance is attributable to an abrupt generation of mass unbalance or to a thermal bow of the rotor shaft, and displaying the result of the judgment. The analysis of the vibration component is made in real time or making use of data stored in the past.

Consideration of monitoring on shaft vibration.

To monitor the shaft vibration of a rotary machine, the rotating pulse signal and the shaft vibration signal are detected by one vibration sensor, and vibration data is derived from this measured result by data processing. The vibration wave is analyzed, and the characteristics of the shaft vibration are gained. This method is applied to a measurement of the shaft vibration of a vertical-type rotary machine. A method by which the position of a rotor on a vertical direction is gained, is shown. This method is applied to a rotary machine. From the measurement of the position of the rotor on the vertical direction, the state of the rotor and the variance of the bearing gap according to the rotation are known in the rotation. By use of this result, we can monitor the magnitude of the abrasion of the bearing.