• Title/Summary/Keyword: Rotor Misalignment

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The Performance Analysis of the Parameter Extracting Technique for the Vibration Monitoring System in High Voltage Motor (고압전동기용 진동 감시 시스템의 계수 추출기법 성능 분석)

  • Park, Jung-Cheul;Lee, Dal-Ho
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.5
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    • pp.529-536
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    • 2019
  • In this paper, the signals of the sensor for extracting characteristic parameters of the rotor are collected and the performance of the extraction technique is analyzed. To this end, a vibration test league was developed for conducting model tests to analyze the signal characteristics under normal operation. As a result, it is judged that no change in the measured the raw data amplitude will occur in the acceleration sensor with the unbalanced mass measured from the acceleration sensor. Performing FFT showed a significant increase in amplitude of the rotational frequency of 20 Hz as the unbalanced mass increased. The analysis results according to the change in the unequal mass of the speed sensor also showed a significant increase in the 1X Harmonics component, such as the acceleration sensor. There was no change in the amplitude of the acceleration sensor data when the misalignment occurred, and for the Envelope data, the amplitude of 2X (40 Hz) was increased depending on the degree of misalignment. The velocity sensor at change of misalignment also showed similar results to the acceleration sensor, and the peak was reduced at 600 Hz as the load increased in the frequency spectrum.

Control of Internal Packing Seal Clearances Considering for Shaft Behavior During Steam Turbine Operation (증기터빈 운전중 축 거동을 고려한 내부단 패킹실의 틈새 관리)

  • Pack, Min-Sik;Lee, Si-Yeon;Yang, Bo-Suk;Choi, Sung-Choul;Lee, Jae-Geun
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1715-1720
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    • 2004
  • This paper presents the characteristics of internal clearances for the interstage of blades and shaft gland seals on the steam turbine which are installed in tandem compound. Internal clearances was changed when the rotor turned in the cylindrical sleeve bearing due to the generation of oil film wedge. This presented concern is very useful to prevent the rubbing damage of seal edge between the fixed and moving parts in steam turbine due to the misalignment at the rotating and stationary parts. This method is applied for the unbalanced clearances distribution to the left and right sides in the turbine casing. A considerable amount of unbalanced clearances distribution trend is determined according to the rotating speed of rotor, size and type of proceeding bearing, oil viscosity, surface roughness of bearing and shaft, oil temperature, oil pressure and bearing load.

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Compensation of Initial Position Error and Torque Ripple in Vector Control of Two-phase Hybrid Stepping Motors (2상 하이브리드 스테핑 모터의 벡터 제어 시 초기 각 오차 및 토크 리플 보상)

  • Do-Hyun, Kim;Sang-Hoon, Kim
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.6
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    • pp.481-488
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    • 2022
  • This study proposes compensation methods for the initial position error and torque ripple in vector control of two-phase hybrid stepping motors. Stepping motors have an asymmetrical structure due to misalignment, such as the eccentricity generated by the manufacturing and assembly process. When vector control is applied using the position information measured by an incremental encoder attached to the rotor shaft of such stepping motors, the following problems occur. First, an initial position error occurs during the forced excitation process for the initial rotor position alignment. Second, torque ripple corresponding to the mechanical rotation frequency is generated. In this study, these non-ideal phenomena that occur in vector control of the stepping motor are analyzed, and compensation methods are proposed to eliminate them. The validity of the proposed initial position error and torque ripple compensation methods is verified through experiments on a two-phase hybrid stepping motor drive system.

A study on wind load characteristics of wind turbines (풍력발전기의 풍하중특성에 관한 연구)

  • Kim, Jung-Su;Park, Noh-Gill;Kim, Young-Duk;Kim, Su-Hyub
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2010.10a
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    • pp.124-129
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    • 2010
  • Wind load characteristics is investigated for vibration analysis of wind turbine gearbox. A normal wind model assumed, of which the wind velocity is increased according to the height from ground. A blast wind model is assumed, of which the maximum velocity is located at the center and the velocity profile is normally distributed. The periodical torque and bending moments transmitted to the main shaft of wind turbine are investigated. The average values and the harmonic terms of the transmitted moments are studied on the wind direction of range $-45^{\circ}{\sim}45^{\circ}$ and the bending moment characteristics are examined, which is regarded as the main source of the misalignment of gear train.

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Hall Sensor Fault Detection and Fault-Tolerant Control of High-Speed PMSM Drive System (고속 영구자석 동기전동기 구동장치의 홀센서 고장검출 및 보호제어)

  • Jang, Myung-Hyuk;Lee, Kwang-Woon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.3
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    • pp.205-210
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    • 2013
  • This paper presents a novel hall sensor fault detection and fault-tolerant control method for a high-speed permanent magnet synchronous motor (PMSM) drive system. A phase locked loop (PLL) type position estimator is used with a conventional interpolation based rotor position estimator to reduce position errors due to misalignment of hall sensors. The expected trigger time of hall sensor's output is used for detecting hall sensor fault condition and the PLL type position estimator is reconfigured for fault-tolerant control at the hall sensor fault condition. The proposed method can minimize current ripples during the transition from sensored control using hall sensors to sensorless control. Experimental results have been proposed to prove the validity of the proposed method.

Image recognition technology in rotating machinery fault diagnosis based on artificial immune

  • Zhu, Dachang;Feng, Yanping;Chen, Qiang;Cai, Jinbao
    • Smart Structures and Systems
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    • v.6 no.4
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    • pp.389-403
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    • 2010
  • By using image recognition technology, this paper presents a new fault diagnosis method for rotating machinery with artificial immune algorithm. This method focuses on the vibration state parameter image. The main contribution of this paper is as follows: firstly, 3-D spectrum is created with raw vibrating signals. Secondly, feature information in the state parameter image of rotating machinery is extracted by using Wavelet Packet transformation. Finally, artificial immune algorithm is adopted to diagnose rotating machinery fault. On the modeling of 600MW turbine experimental bench, rotor's normal rate, fault of unbalance, misalignment and bearing pedestal looseness are being examined. It's demonstrated from the diagnosis example of rotating machinery that the proposed method can improve the accuracy rate and diagnosis system robust quality effectively.

Diagnosis of rotating machines by utilizing a back propagation neural net

  • Hyun, Byung-Geun;Lee, Yoo;Nam, Kwang-Hee
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.522-526
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    • 1994
  • There are great needs for checking machine operation status precisely in the iron and steel plants. Rotating machines such as pumps, compressors, and motors are the most important objects in the plant maintenance. In this paper back-propagation neural network is utilized in diagnosing rotating machines. Like the finger print or the voice print of human, the abnormal vibrations due to axis misalignment, shaft bending, rotor unbalance, bolt loosening, and faults in gear and bearing have their own spectra. Like the pattern recognition technique, characteristic. feature vectors are obtained from the power spectra of vibration signals. Then we apply the characteristic feature vectors to a back propagation neural net for the weight training and pattern recognition.

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Vibration Characteristic Study of Bevel Geared System Using Transfer Matrix Method (전달행렬법을 이용한 베벨기어 시스템의 진동특성연구)

  • Lee, Hyoung-Woo;Bae, Myung-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.4
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    • pp.118-126
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    • 2008
  • A new approach to the critical speed calculation of general multi-mesh gear chain system included bevel gear is presented. A transfer matrix mode! based on Hibner's branch method is developed and the natural properties of the branched rotor system are calculated with using the ${\lambda}$-matrix formulation. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the neighborhood of the operating speed, there are the two critical speeds amplifying the first mode and the eighth mode.

Examination of the Intermittent High Vibration by the Accumulated Carbide at Oil Deflector of a Steam Turbine for Power Plant (발전용 증기터빈의 Oil Deflector부 탄화물 퇴적에 의한 간헐적 고진동 현상 규명)

  • 양승헌;박철현;김재실;하현천
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.190-195
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    • 2002
  • The intermittent high vibration has been occurred one or two times a day for a 500MW large steam turbine during 5 months. This abnormal vibration was caused by the rubbing between the rotor and the carbide accumulated on the seal tooth of oil deflector. It was found that the accumulated carbide was insulation material installed on the HIP casing from the examination of the chemical composition. Also, this paper presents the mechanism of the intermittent high vibration and the proper method to eliminate this vibration problem. This result would be good practice to find the solution of similar high vibration in the steam turbines for power plant as well as industrial rotating machineries.

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Examination of the Periodic High Vibration by the Accumulated Carbide at Oil Deflector of a Steam Turbine for Power Plant (발전용 증기터빈의 Oil Deflector부 탄화물 퇴적에 의한 주기적 고진동 현상 규명)

  • 양승헌;박철현;김재실;하현천
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.11
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    • pp.897-903
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    • 2002
  • The periodic high vibration has been occurred one or two times a day for a 500 MW large steam turbine during 5 months. This abnormal vibration was caused by the rubbing between the rotor and the carbide accumulated on the seal tooth of oil deflector. It was found that the accumulated carbide was insulation material installed on the HIP casing from the examination of the chemical composition. Also, this paper presents the mechanism of the periodic high vibration and the proper method to eliminate this vibration problem. This result would be good practice to find the solution of similar high vibration in the steam turbines for power plant as well as industrial rotating machineries.