| 摘要 |
PROBLEM TO BE SOLVED: To find out the generation of a foreign matter in its early stages in a hydraulic machinery and thereby enhance the maintenance and reliability of the hydraulic machinery by making calculation through the oscillation of a guide vane detected by oscillation detection means, and hence determining an abnormality of the hydraulic machinery. SOLUTION: A guide vane 1 comprises a blade 2 and a driving shaft 3 connected thereto, and the driving shaft 3 is supported rotatably by a bearing 4. On the one hand it is provided with a strain gauge 6 spread over the surface of the driving shaft 3 and a strain amplifier for amplifying its output, and both of them are connected with wire through a central bore of the driving shaft 3. The intensity of strain of the guide vane 1 outputted by the strain amplifier 7 is inputted so that a calculation circuit 8 as determination means operates to diagnose the occurrence of foreign matter. When a foreign matter hits against the blade 2 of the guide vane 1, and amplitude of strain generated on the driving shaft 3 increases for a certain period of time. At this time, a comparison is made between a measured amplitude of strain of the driving shaft 3 and a threshold value, and as the measured value exceeds the threshold value, the occurrence of foreign matter is determined.
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