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Non-contact acoustic emission measurement for condition monitoring of bearings in rotating machines using laser interferometry

 
OHTA Yasufumi, SARUTA Koichi, and UEDA Masashi
 
Operation and Maintenance Technology Development Group, FBR Plant Engineering Research Center, Japan Atomic Energy Agency, 1 Shiraki, Tsuruga, Fukui 919-1279 Japan (ohta.yasufumi@gmail.com)
 
Abstract: For advanced maintenance and safety in nuclear power plants, it is necessary to combine various technologies that are used to monitor the status of different equipment. Non-contact measurement methods offer technical advantages over contact measurement methods, such as the ability to perform spot measurements, adapt to high-temperature environments, and inspect dynamic parts. The acoustic emission (AE) method can detect earlier abnormal signs in bearings than vibration analysis, which is commonly used in power plants. The AE method is also able to detect various other events such as wear and leakage of materials. However, currently, non-contact AE measurement is not used for condition monitoring in power plants. To verify the feasibility of a non-contact AE measurement method using laser interferometry for condition monitoring technology, laboratory tests were conducted using a rotating machine fitted with bearings that had deliberately been made defective. The AE signals propagating from these defects were measured using a Michelson interferometer on the rotating polished shaft, and a piezoelectric sensor positioned on the bearing housing. This paper demonstrates that the non-contact AE method can detect various stages of deterioration in bearings, and therefore, the method can be considered as a useful future tool for condition monitoring of bearings in rotating machines.
Keyword: acoustic emission; non-contact measurement; laser interferometer; condition monitoring; bearing
 
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