• Journal of Biosystems Engineering
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• v.26 no.6
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• pp.503-508
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• 2001

In this paper, time-fiequency analysis and multi-dimensional spectral analysis methods are applied for source identification and diagnosis of non-stationary sound/vibration signals. Sound or vibration problems of general vehicle and agricultural machinary are under 500 Hz. So We used linearly increased chirp signals under 500 Hz. By checking the coherences on concerned time, fur time-variant non-stationary signals, this simulation it very well coincident to expected results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.122-127
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• 1994

본 논문에서는 산업용으로서 널리 이용되고 있는 3상 유도전동기의 전기적결함에 의해 발생하는 전자진동문제를 체계적으로 검토하고, 이를 이용하여 전동기 진동이 진단법을 신경회로망을 이용하여 구축한다. 그리고 그중에서 비교적 자주 발생하는 공극(air-gap)의 정적편심에 대해 실험을 수행하고, 그 결과를 신경회로망을 이용한 진단법에 적용하여 본 진단법의 유용성을 확인한다. 또한 현장에서 발생된 전기적인 결함에 대한 진동측정 data를 이용하여 진단이 정상적으로 수행되는가를 조사하여 본 진단법의 가능성을 조사한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.350-353
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• 1995

본 연구에서는 회전기계의 진동신호를 검출, 신호처리, 이상판별, 이상진단 및 경향 예측을 수행하는 이상진동진단 시스템을 개발하였다. 이 시스템의 특징은 GUI를 지원하고 풀다운 메뉴방식을 통한 일관된 환경을 제공하며, 키보드 사용이 거의 없이 마우스만으로 모든 처리가 가능하다. 또한 각 모듈을 하나의 통합환경 내에서 처리된다. 금후 이상진단부분을 보다 개선하여 정밀진단이 이루어지도록 확장하여 갈 예정이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.360-366
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• 1995

국내 발전소에서 사용하고 있는 대형 회전 기계인 터빈의 상태 진단 기능을 높이기 위하여 터빈에서 발생 될 수 있는 이상 진동의 특성을 파악하고 이를 이용하여 이상 진동의 발생 가능성을 확률적으로 출력하는 새로운 알고리즘을 개발하였으며, C-언어로 프로그램하여 이를 검증하였다. 이상과 같이 본 연구에서 제안한 알고리즘을 이용한 자동 진단 시스템을 통하여 각각의 이상 진동에 대한 진단을 수행한 결과 양호한 판정 결과를 보였으며, 터빈 이상 진동에 대한 자동 진단의 가능성을 입증하였다.

• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.88-95
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• 1998

Vibration analysis of rotating machinery can give an indication of possible faults thus allowing maintenance before further damage occurs. Current predictive maintenance system installed in Pyung-tak has the ability to diagnose the mechanical problems within the LNG Pump when the vibration exceeds preset overall alarm levels. In this study, LNG pump auto-diagnosis system based upon Windows NT and DSP Board is developed. This system analysis velocity signal acquired from dual accelerometer input monitor system to diagnose pump condition. Many plots which display machine condition are shown and features of vibration are stored in every time. If the fault is found, the system diagnoses automatically using expert system and trend monitoring. Operator checks pump condition intuitively using personal computer monitor.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.645-648
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• 2003

Induction motors are a critical component of industrial processes. Sudden failures of such machines can cause the heavy economical losses and the deterioration of system reliability. Based on the reliability and cost competitiveness of driving system (motors), the faults detection and the diagnosis of system are considered very important factors. In order to perform the faults detection and diagnosis of motors, the vibration monitoring method and motor current signature analysis (MCSA) method are emphasized. In this paper, MCSA method is used for induction motor fault diagnosis. This method analyses the motor's supply current. since this diagnoses faults of the motor. The diagnostic algorithm is based on the principal component analysis(PCA), and the diagnosis system is programmed by using LabVIEW and MATLAB.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.699-703
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• 1999

An experimental study to identify the energized status of the 22.9kV underground power cable by the detection of vibration has been performed. We have derived that there exists vibration at double the line frequency in live cables by electromagnetic force. The relative amplitudes of the cable vibration according to the energized status of the cable were calculated by computer simulation. The cable vibration can also be picked up by accelerometer. A prototype was tested on the underground distribution system in Chonan substation, KEPCO. Comparison between simulation results and field test results was performed. The results showed that the energized status of the calble can be identified by measuring the vibration of the cable using accelerometer.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1020-1025
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• 2007

The reciprocating type hydrogen compressor is for high pressure and volume. However this type compressor makes pulsation caused by mechanical characteristic. This type compressor also makes noise and vibration that cause negative effect to machine and working condition. Therefore, diagnosis and countermeasure are needed to decrease vibration for safety on hydrogen compressor. therefore in this paper, the numerical analysis and vibration measurement is conducted in order to investigate vibration characteristic and to evaluation vibration condition, Respectively

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.243-245
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• 2005

Condition monitoring is desirable for increasing machinery availability, reducing consequential damage, and improving operational efficiency. In this paper, a model-based method using neural network modeling of induction noter in vibration spectra is proposed for machine fault detection and diagnosis. The short-time Fourier transform (STFT) is used to process the quasi-steady vibration signals to continuous spectra so that the neural network model can be trained with vibration spectra. And the faults are detected from changes in the expectation of vibration spectra modeling error. The effectiveness of the proposed method is demonstrated through experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.179-184
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• 2002

In this study, we developed a portable device which can monitor and analyze vibration signals from machines. This system consists a PDA loading the program for vibration analysis and A/D board for vibration acquisition. A PDA is smaller than the palm of the hand, but it has a powerful computing ability as much as an IBM compatible PC with a Pentium 100MHz CPU. The A/D board developed in this study supports LAN interface using TCP/IP communication protocol. The application program for vibration analysis includes signal processing module, fault diagnosis module, data store module, and plot display module. MS visual embedded C＋＋ 3.0 was used to developed the program.