• Title/Summary/Keyword: Excitation system

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Comparison of Fatigue Damage of Linear Elastic System with Respect to Vibration Input Conditions (입력가진 조건에 따른 선형 시스템의 피로손상도 비교 평가)

  • Heo, Yun Seok;Kim, Chan-Jung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.6
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    • pp.437-443
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    • 2014
  • Vibration testing is conducted for evaluate the fatigue resistance of responsible system over excitation situations and two kinds of vibration profiles, harmonic or random, are widely used in engineering fields. Harmonic excitation profile is adequate for the rotating machinery that is primarily exposed to the orderly excited force subjected for a rotating speed; Random profile is suitable for the non-stationary vibration input, that is a ground excitation for example. Recently, the sine on random(SOR) testing method was sometimes considered to represent the real excitation conditions since the measured response signals of a target system, expecially for moving mobility, shows usually a mixture of them. So, it is important to understand the accumulated fatigue damage over different excitation patterns, harmonic and/or random, to determine the efficient vibration profile of a target system. A uniaxial vibration testing with a notched simple beam was introduced to evaluate the fatigue damage for different excitation profiles and the best choice of vibration profile was concluded from those comparison of calculated fatigue damages.

Comparison of fatigue damage of linear elastic system with respect to vibration input conditions (입력가진 조건에 따른 선형 시스템의 피로손상도 비교 평가)

  • Kim, Chan-Jung;Heo, Yun Seok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.04a
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    • pp.340-345
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    • 2014
  • Vibration testing is conducted for evaluate the fatigue resistance of responsible system over excitation situations and two kinds of vibration profiles, harmonic or random, are widely used in engineering fields. Harmonic excitation profile is adequate for the rotating machinery that is primarily exposed to the orderly excited force subjected for a rotating speed; Random profile is suitable for the non-stationary vibration input, that is a ground excitation for example. Recently, the sine on random (SOR) testing method was sometimes considered to represent the real excitation conditions since the measured response signals of a target system, expecially for moving mobility, shows usually a mixture of them. So, it is important to understand the accumulated fatigue damage over different excitation patterns, harmonic and/or random, to determine the efficient vibration profile of a target system. A uniaxial vibration testing with a notched simple beam was introduced to evaluate the fatigue damage for different excitation profiles and the best choice of vibration profile was concluded from those comparison of calculated fatigue damages.

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Excitation System Stress in Synchronous Machine Connected to HVDC System (HVDC 단에 연결된 동기기의 여자시스템 스트레스)

  • Kim, Chan-Gi
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.8
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    • pp.482-492
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    • 2002
  • This paper deals with overvoltage stresses in the field circuit of synchronous machine connected to HVDC terminal. A load rejection of the HVDC may cause generator in the station to become self-excited, resulting in a severe system overvoltage. This paper shows that violent field current oscillations can be produced by resonance between the machine inductance and the terminal capacitance. As most conventional excitation system do not allow reverses current, new topology of excitation system to allow reverse current is proposed. the proposed system can limit the rate of rise of terminal voltage during conditions of self excitation. Apart from these simulations, the nature(Magnitude and frequency) of the field transient state is explained mathematically. Finally, the EMTDC program is used for the simulation studies.

Development of the Object Transport System using Ultrasonic Wave Excitation (초음파 여기를 이용한 물체 이송 시스템 개발에 관한 연구)

  • Jeong, Sang-Hwa;Shin, Byung-Su;Cha, Kyoung-Rae;Song, Suk;Lee, Kyung-Hyung
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.371-375
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    • 2003
  • In recent years, as the semiconductor and the optical industry grows, the necessity of the transporting system for semiconductor and precision optical lens without damage increases. The transport system using ultrasonic wave is very suitable for this area. In this paper the object transport system using the excitation of ultrasonic wave is proposed. The experiments for finding the optimal excitation frequency, finding phase-difference between two ultrasonic wave generators are performed. The effect of transporting speed according to the change of weight and amplification voltage are verified. In addition, the system performance for actual use is evaluated.

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Dynamic response for electromechanical integrated toroidal drive to electric excitation

  • Xu, Lizhong;Hao, Xiuhong
    • Structural Engineering and Mechanics
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    • v.26 no.6
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    • pp.635-650
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    • 2007
  • In this paper, the equivalent exciting force caused by electric excitation is derived. By dividing load and displacement vectors into mean values and time-varying ones, the dynamic equations of the system are transformed into linear ones for time-varying portion of the displacements. The analytical equations of the forced time responses of the drive system to electric excitations are obtained. Using the Laplace transformation, the transfer function of the drive system is obtained. These equations are used to analyze the time and frequency responses of the drive system to the electric excitation. It is known that electric excitation can cause forced responses of the drive system, the total dynamic responses are decided by three phase exciting voltages, exciting frequency and natural frequencies of the drive system, and the drive parameters have obvious influence on the time and frequency responses.

A study on the static excitation system using Self-Tuning Adaptive Control Algorithm (자기동조 제어알고리즘을 이용한 정지형 여자제어 시스템에 관한 연구)

  • Yoon, G.G.;Lim, I.H.;Kim, C.K.;Kim, K.C.;Rhew, H.W.;Kim, H.P.
    • Proceedings of the KIEE Conference
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    • 1997.07b
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    • pp.660-662
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    • 1997
  • A new improved excitation control system for power plant synchronous generators has been developed by KEPRI (Korea Electric Power Research Institute). The reliability of the excitation system is increased by designing a dual channel automatic voltage regulator(AVR). Also the performance of the excitation system is improved by Self-Tuning adaptive Controller. A software package is developed for the excitation control system, and a field test is conducted to verify the system performance.

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An Enhanced Excitation Source in LPC Vocoder (LPC Vocoder 의 Excitation Source 개선에 관한 연구)

  • Jeon, Ji-Ha;Lee, Keun-Young
    • Proceedings of the KIEE Conference
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    • 1987.07b
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    • pp.881-883
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    • 1987
  • This paper decribes a new technique for the generation of excitation sources in LPC system. We synthesize a speech signal using several excitation sources, according to residual signal energy and ZCR(zero Crossing Rate). One of the excitation sources mix the double differentiated glottal wave form source and noise source. As a result, we got improved speech signal than that produced by conventional LPC system.

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Introduction of Sensors in Turbine Control Systems and Excitation Systems (발전소 터빈 제어시스템과 여자시스템에 사용되는 센서 소개)

  • Shin, Man-Su;Woo, Ju-Hee;Kim, Jong-An;Choe, In-Gyu;Ryu, Ho-Seon;Jeong, Tae-Won
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1818-1819
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    • 2011
  • Turbine control system and excitation system have close relationship in the dynamic and real power system. Turbine control systems control the active power of generator and excitation systems control the voltage and reactive power of generator. The several sensors' characteristics in turbine control systems and excitation systems were reviewed.

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A Study of Function Verification of Digital Excitation System with Real Time Simulator (시뮬레이터 탑재형 디지털 여자시스템 기능검증 시험에 관한 연구)

  • Ryu, Ho-Seon;Shin, Man-Su;Lee, Joo-Hyun;Lim, Ick-Hun
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1191-1192
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    • 2011
  • We released new triple redundant digital excitation system with real time generator-turbine simulator. One of its great merits is the real time generator-turbine simulator when it was compared with the other products. If excitation system is tripped by unexpected faults, Maintenance man can do easily performance test of digital excitation control board, sequence relay and thyristor switching device of phase controlled rectifier without manufacturer's support. For the verification of this system, It was tested with an actual excitation system implemented on 5kVA M-G Set. After finishing the tests, the trial product will be installed and operated at a 500MW thermal power plant.

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Investigation of Excitation System for Nuclear Emergency Diesel Generator (원전 비상디젤발전기 여자시스템 고찰)

  • Shin, Man-Su;Lee, Joo-Hyun;Lim, Ick-Hun;Jeong, Tae-Won
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1894-1895
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    • 2007
  • It is excitation system for nuclear emergency generator that is to startup automatically and sequentially supply essential loads with power. There are static type and alternating exciter, etc in its excitation system. An object of study is static excitation system which power is taken from power potential transformer and power current transformer. It is to complement curtailment of excitation system ability at happening short accidents. And Startup mode are quick startup and slow startup, etc. Its characteristic is looked into in this paper.

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