• Title/Summary/Keyword: winding number

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A study on Quench Characteristics considering Winding Tension in Superconducting Coil using Acoustic Emission Technique (권선장력을 고려한 초전도 계자코일의 퀀치특성 및 AE 신호특성에 관한 연구)

  • 이준현;이민래;손명환;권영길
    • Progress in Superconductivity and Cryogenics
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    • v.1 no.2
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    • pp.8-14
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    • 1999
  • In this study, acoustic emission(AE) technique has been applied to detecting quench which is one of the serious peoblems to assure the integrity of superconducting coil at cryogenic temperature. The characteristics of AE parameters have been analyzed by correlating with the number of quenches, whinding tension of superconducting coil and charge rate of transport current. The quench localization was also performed using AE signals and there was also good correlation between quench current and AE parameters such as AE energy and AE events. In this study, it was confirmed that AE signals were mainly due to the conductor motion which caused by premature quenching. It was also found that optimized winding tension at superconducting coil was needed to prevent quench caused by conductor motion.

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Characteristics of RFCT for Partial Discharge Measurement in the Stator Winding of Rotating Machines (회전기 고정자 권선의 부분방전 측정용 RFCT 특성)

  • Kang, Dong-Sik;Yoon, Dae-Hee;Hwang, Don-Ha;Kim, Yong-Joo;Chang, Ki-Chan;Song, Sang-Ock
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1616-1618
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    • 2001
  • In recent the on-line partial discharge (PD) measurement using sensors, such as EMC, SSC, RTD and RFCT, as an indicator of stator winding insulation condition has been developed. RFCT sensor was placed arounding a grounding lead of surge capacitor to detecting PD. Trend of PD magnitude/phase angle/pulse number over time are useful parameter to diagnosis aging state. We have developed Radio Frequency Current Transformer(RFCT) sensor which is suitable for PD diagnostic measurement in 6.6kV rotating machines. In this paper, we describe the characteristics of RFCT sensor, such as frequency and PD magnitude using 6.6 kV model stator winding in Lab.

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Rotor Design on Torque Ripple Reduction for a Synchronous Reluctance Motor with Concentrated Winding using Response Surface Methodology (반응표면법을 이용한 집중권선 동기 릴럭턴스 전동기의 토크 리플 저감에 관한 회전자 설계)

  • Park, Jung-Min;Lee, Jung-Ho
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.12
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    • pp.623-627
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    • 2006
  • This paper deals with the optimum rotor design solution on torque ripple reduction for a SynRM with concentrated winding using response surface methodology (RSM). The RSM has been achieved to use the experimental design method in combination with finite element method (FEM)and well adapted to make analytical model for a complex problem considering a lot of interaction of design variables. Comparisons are given with characteristics of a SynRM according to flux barrier number, flux barrier width variation, respectively.

Study of Winding Method to Reduce Stray Loss and Stator Core Vibration of Synchronous Machine

  • Hiramatsu, Daisuke;Sutrisna, Kadek Fendy;Ishizuka, Hiroaki;Okubo, Masashi;Tsujikawa, Kazuma;Ueda, Takashi;Hachiya, Hideyuki;Mori, Junji;Aso, Toshiyuki;Otaka, Toru
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.3
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    • pp.313-320
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    • 2013
  • The fractional slot windings are widely used in rotating machine in order to increase the flexibility of design and improve the voltage waveform. However, the MMF wave of fractional-slot windings are found to contain unique harmonic component, which are designated as even order space flux harmonics, fractional number flux harmonics, or both. They may cause stray loss and stator core vibration. This paper proposes new winding methods "novel interspersed windings" and "expanded group windings" to reduce these harmonics. The advantages of two proposed windings are verified by using numerical analysis and measurement test of winding model.

A Study on a Boost-Input Self-Driven Active Clamp ZVS Converter (자기구동 능동 클램프를 이용한 부스트 입력형 ZVS 컨버터에 관한 연구)

  • Jin, Ho-Sang;Kim, Hee-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.781-788
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    • 2011
  • This paper proposes a boost-input self-driven active clamp ZVS converter eliminating the extra dirve circuit for the active clamp switch. The converter used the auxiliary winding of the transformer to drive the active clamp switch and to achieve asymmetrical duty control. This paper presents the operation principle and the analyzed results of dynamic characteristics including steady state characteristics of the converter proposed. The experimental results were used to verify the theoretical predictions. A 300W (15V/20A) prototype converter that only exhibited 2-turn winding number in the auxiliary winding was sufficient to drive the active clamp switch on the input voltage of 80V. Finally, the maximum efficiency of 91.2% was achieved for the prototype converter and the proposed converter had stable closed loop characteristic with phase margin $55^{\circ}$.

Pattern of partial discharge for stator windings fault of high voltage motor (고압전동기 고정자권선 결함 부분방전패턴)

  • Park, Jae-Jun;Kim Hee-Dong
    • The Journal of Information Technology
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    • v.7 no.1
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    • pp.155-161
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    • 2004
  • During normal machine operation, partial discharge(PD) measurements were performed with turbine generator analyzer(TGA) in imitation stator winding of high voltage motors. The motor was energized to 4.47kV, 6.67, respectively. Applied voltage to Imitation winding was used two voltage level, 4.47[kV] and 6.67[kV]. Motors having imitation stator winding were installed with 80pF capacitive couplers at the terminal box. Case of PD Pattern regarding applied voltage phase angel, the PD patterns were displayed two dimensional and three dimensional. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). As the result, we could discrimidate using TGA the difference of internal and surface discharge for imitation stator winding. We have used the other technique, in order to feature extraction of faulty signals on stator winding, Daubechies Discrete wavelet transform and Harmonics analysis(FFT) about faulty signals.

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Equivalent Mechanical and Thermal Properties of Multiphase Superconducting Coil Using Finite Element Analysis (유한요소해석을 이용한 다상의 초전도 코일에 대한 기계적 열적 등가 물성)

  • Sa, J.W.;Her, N.I.;Choi, C.H.;Oh, Y.K.;Cho, S.;Do, C.J.;Kwon, M.;Lee, G.S.
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.975-980
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    • 2001
  • Like composite material. the coil winding pack of the KSTAR (Korea Superconducting Tokamak Advanced Research) consist of multiphase element such as metallic jacket material for protecting superconducting cable, vacuum pressurized imprepregnated (VPI) insulation, and corner roving filler. For jacket material, four CS (Central Solenoid) Coils, $5^{th}$ PF (Poloidal Field) Coil, and TF (Toroidal Field Coil) use Incoloy 908 and $6-7^{th}$ PF coil, Cold worked 316LN. In order to analyze the global behavior of large coil support structure with coil winding pack, it is required to replace the winding pack to monolithic matter with the equivalent mechanical properties, i.e. Young's moduli, shear moduli due to constraint of total nodes number and element numbers. In this study, Equivalent Young's moduli, shear moduli, Poisson's ratio, and thermal expansion coefficient were calculated for all coil winding pack using Finite Element Method.

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Hysteresis Characteristics of Flux-Lock Type Superconducting Fault Current Limiter (자속구속형 고온초전도 사고전류제한기의 히스테리시스 특성)

  • Lim, Sung-Hun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.1
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    • pp.66-70
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    • 2007
  • For the design to prevent the saturation of the iron core and the effective fault current limitation, the analysis for the operation of the flux-lock type superconducting fault current limiter (SFCL) with consideration for the hysteresis characteristics of the iron core is required. In this paper, the hysteresis characteristics of the flux-lock reactor, which is an essential component of the flux-lock type SFCL, were investigated. Under normal condition, the hysteresis loss of the iron core in the flux-lock type SFCL does not happen due to its winding structure. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. From the analysis for both the hysteresis curves and the fault current limiting characteristics due to the number of turns for the 1st and 2nd windings, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

Electrical and Optical Characteristics by Ferrite for Electrodeless Fluorescent Lamp (무전극 형광램프용 페라이트에 따른 전기적 및 광학적 특성)

  • Pack Kwang-Hyeon;Yang Jong-Kyung;Lee Jong-Chan;Park Dae-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.2
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    • pp.200-206
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    • 2006
  • An electric power efficiency of electrodeless fluorescent lamp depens on a big relative property of gas, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. in lamp. We used magnetic substance that opens self-examination material of electrodeless fluorescent lamp antenna. We used Mn-Zn type as the Ferrite. We have examined resistance, impedance and Q-factor's frequency characteristic by ferrite. Coil turns were changed from 13 to 15 turns to recognize brightness change of lamp by winding number. Optical equipment (LS-100) was used to measure brightness. We could know Q-factor's difference according to material is important part of antenna design. When an electrodeless fluorescent lamp was made using T company's PE22, it showed the highest brightness. As number of winding is increased the brightness increased, and starting characteristic became good.

Brightness Property by Ferrite on Electroness Flurescent Lamp (무전극 형광램프용 페라이트에 따른 휘도특성)

  • Pack, Gwang-Hyeon;Lee, Jong-Chan;Choi, Young-Sung;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.607-610
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    • 2004
  • An electric power efficiency of electrodeless fluorescent lamp has big relativie propertye of gas in lamp, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. We used magnetic substance that open self-examination material of electrodeless fluorescent lamp antenna. Ferrite that is used in this experiment was Mn-Zn type. Coill turn was changed from 13th to 13th turn to recognize brightness change of lamp by winding number. Optical equipment that used in an experiment was used to measure brightness (LS-100). When an electrodeless fluorescent ]amp was made using and T company's PE22, was it showed the highest brightness. As number of winding is increased the brightness increased, and starting characteristic became good.

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