| 摘要 |
PURPOSE:To early detect abnormality by detecting AE (Acoustic Emission) signal generated in a bearing supporting a rotary shaft, and judging the bearing to be abnormal when the duration of AE signal satisfying a designated condition exceeds a reference time. CONSTITUTION:When an oil film is broken due to any cause during operation of a rotary machine and a rotary shaft 1 is brought into metal to metal contact with a bearing 2, generally the bearing 2 which is made of soft material is plastic-deformed, and AE signal corresponding to its strength is output from AE sensor 3. The AE signal is sent through an amplifier 5 and a waveform processing device 6 to a level setting portion 7, and a signal of a determined level is selected to be input to a pulse counter 11 through a gate shaping device 8. The pulses during a set time are counted by the counter, and the count number is compared with a preset number by a comparator 13. If the count number is larger than the preset number, an alarm and a trip signals are output from an output circuit 15.
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