CONTACTLESS MEASURING DEVICE FOR OSCILLATION OF DRIVING BLADE

摘要

PURPOSE:To simplify the system constitution and make it unnecessary to provide a reference point such as a projection on a shaft, by lowering the reflection factor of one driving blade and obtaining a driving blade pulse train with dropout of one pulse for every one rotation and generating a rotation reference pulse on a basis of this pulse train. CONSTITUTION:Tips of driving blades 1 of a rotary machine 2 are irradiated with the light from a light source 20, and the reflected light is detected to detect optically the oscillation state of driving blade without contact; and the tip of one driving blade 1a out of plural driving blades 1 is painted black to weaken its reflected light. The reflected light is converted to an electric signal in a photoelectric converting device 23 and is inputted to a trigger level adjusting device 24, and only pulses having a certain level are permitted to pass through. Since the pulse concerning the driving blade 1a painted black has a level lower than a level l because of the weak reflected light, a pulse train where the pulse concerning the driving blade 1a is eliminated is obtained through shaping of a pulse shaping device 25. A rotation reference pulse is obtained on the basis of this pulse train to measure the amplitude of oscillation of each driving blade.