| 摘要 |
PURPOSE:To surely and with high accuracy measure by an axis a vibration mode in which a blade and the axis are coupled and the blade oscillates mainly, by providing alternately a minute ruggedness in the peripheral direction on the outside periphery of a rotation axis, and also, providing the ruggedness on the surface of the rotation axis so as to be parallel to the axial direction of the rotation axis. CONSTITUTION:At the time of measuring a torsional vibration of a turbine generator, especially, a torsional vibration coupled by a blade and an axis of higher order, it can be executed by constituting a striped pattern at an interval of 0.5-1mum on the axial periphery, and measuring a variation of the number of counting within a prescribed time of the number of its stripes. Subsequently, with respect to a wide band 27 of a bright and dark pattern, which has been fixed firmly to an axis 26, a light beam is made incident from a laser oscillator 30 of a detector 29, a reflected light from a bright pattern 28 is converted to an electric signal by a photodetector 33, and the number of a prescribed time interval of the bright pattern 28 is counted continuously. The detector 29 is installed on the opposite side by 180 deg. from the axis 26, as well, and by adding a signal from the detector 29 by an adder 34, the influence of an axial vibration of the axis 26 is eliminated.
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