| 摘要 |
PURPOSE:To achieve an immediate diagnosis of bearings of rotary machines of utterly different types, by a demodulation processing of output of an acoustic sensor set on a bearing at the both ends thereof to examine the amplitude difference between resulting demodulation signals. CONSTITUTION:Acoustic sensors 3a and 3b are set on bearings 2a and 2b supporting a rotary machine 1 and output of the sensors 3a and 3b are inputted into the demodulation circuits 5a and 5b through amplification circuits 4a and 4b. The demodulation circuits 5a and 5b are respectively made up of detection circuits 6a and 6b and filters 7a and 7b and outputs of the demodulation circuits 5a and 5b are inputted into respective mean circuits 8a and 8b. Then, an output (A) of the mean circuit 8a and an output (b) of the mean circuit 8b are inputted into a bearing abnormality diagnosing circuit 9. The bearing abnormality diagnosing circuit 9 compute an output difference between A and B and when the result exceed the reference value, it outputs a signal to operate an alarm10.
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