• 제목/요약/키워드: dissipation factor

검색결과 394건 처리시간 0.033초

휨핀칭과 에너지 소산능력 (Flexural Pinching and Energy Dissipation Capacity)

  • 박흥근;엄태성
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2003년도 춘계 학술발표회논문집
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    • pp.275-285
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    • 2003
  • Pinching is an important property of reinforced concrete member which characterizes its cyclic behavior. In the present study, numerical studies were performed to investigate the characteristics and mechanisms of pinching behavior and the energy dissipation capacity of flexure-dominated reinforced concrete members. By analyzing existing experimental studies and numerical results, it was found that energy dissipation capacity of a member is directly related to energy dissipated by re-bars rather than concrete that is a brittle material, and that it is not related to magnitude of axial compressive force applied to the member. Therefore, for a member with specific arrangement and amount of re-bars, the energy dissipation capacity remains uniform regardless of the flexural strength that is changed by the magnitude of axial force applied. Due to the uniformness of energy dissipation capacity pinching appears in axial compression member. The flexural pinching that is not related to shear force becomes conspicuous as the flexural strength increases relatively to the uniform energy dissipation capacity. Based on the findings, a practical method for estimating energy dissipation capacity and damping modification factor was developed and verified with existing experiments.

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대용량 발전기 고정자 바의 유전정접 특성 (Characteristics of Dissipation Factor in Large Generator Stator Bars)

  • 김희동;공태식;주영호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.402-403
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    • 2009
  • Accelerated aging tests were conducted under laboratory conditions on two generator stator bars. Electrical stress is applied in No. 1 model stator bar. Electrical and thermal stresses are applied in No. 2 model stator bar. As aging times increased from 0 to 11460h, dissipation factor($tan{\delta}$) test was performed on No. 1 and No.2 model stator bars. The ${\Delta}tan{\delta}$ of No. 1 and No. 2 stator bars increased with increased in aging time.

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유리섬유/폴리에스터 복합재료를 위한 유전 경화 모니터링 (Dielectric Cure Monitoring for Glass/Polyester Prepreg Composites)

  • 김형근;김진국;이대길
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집A
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    • pp.797-803
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    • 2001
  • The on-line cure monitoring of fiber reinforced thermosetting resin matrix composite material was performed for the better quality and productivity during manufacturing. Since the dissipation factor measured by dielectrometry method is dependent on the degree of cure and temperature of resin, in this study, a new method to obtain the degree of cure during on-line cure monitoring for glass/polyester composites was developed by employing a combination function of the temperature and the dissipation factor. Two sensor signals from a K-type thermocouple and an interdigitated dielectric sensor were processed during curing process under various cure cycles. The DSC (Differential Scanning Calorimetry) data was also used for the reference of degree of cure.

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세척과 절연보강에 따른 고압전동기 고정자 권선의 절연상태 분석 (Analysis of Insulation Condition in High Voltage Motor Stator Windings Following Cleaning and Insulation Reinforcement)

  • 김희동
    • 한국전기전자재료학회논문지
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    • 제25권6호
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    • pp.474-480
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    • 2012
  • Diagnostic tests were performed on two high voltage(HV) motor stator windings. These tests included the measurement of insulation resistance, polarization index, AC current, dissipation factor($tan{\delta}$) and partial discharge(PD) magnitude. Surface contamination of HV motor stator windings has an effect on the AC current and $tan{\delta}$. When the stator windings were finished cleaning and insulation reinforcement, the increase rate of AC current(${\Delta}I$) and dissipation factor(${\Delta}tan{\delta}$) were very small compared to those before cleaning. However, the PD magnitude remained the same. These tests show that cleaning and insulation reinforcement of HV motor stator windings can reduce the insulation failure.

도시형 자기부상열차 전력 측정 (Measuring Power Dissipation for Urban Maglev Vehicle)

  • 박정웅;김봉섭;이장열;김행구
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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    • pp.3092-3098
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    • 2011
  • This paper deals with analysis of measuring power dissipation when Maglev is running. With the various running scenarios for Maglev, power dissipation was measured and a comparative analysis of it and wheel-on rails were carried out. The purpose of this paper is to confirm the efficiency and economics on operation of Maglev and reflect detail design later. When the running scenarios of Maglev are the status of landing on and levitation, running at rated acceleration and deceleration and according to changes of velocity, the power dissipation was measured. The measured results are analyzed considering with apparent electric power and active power, reactive power and power factor etc. Due to the limited test track condition, it is very limited to compare and analyze Maglev and general trains. Nevertheless, It is a task of great significance to identify the efficiency and economics on operating Maglev through the results of measuring power dissipation. In the future, measuring power dissipation through more various scenarios will be carried out, and the results will be reflected the design.

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저주파수 전원을 이용한 전력케이블 절연평가에 관한 연구 (Power Cable Insulation Diagnosis Using Low Frequency Power)

  • 김성민;이상훈;장재열
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2011년도 제42회 하계학술대회
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    • pp.1603-1603
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    • 2011
  • As time goes by these cables make a insulation problems, and ask for a preventive diagnosis method. Cable has very high electrostatic capacity and insulation defects mainly caused by water-tree(WT). Dissipation factor test is very useful for detecting WT but it needs huge power supply. In this paper we presented a cable insulation diagnosis by dissipation factor using low frequency power supply.

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적층형 필름 Chip Capacitor 개발 (A Study on the Stacked type Film Chip Capacitor)

  • 송호근;박상식;연강흠;김성호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1991년도 추계학술대회 논문집
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    • pp.73-78
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    • 1991
  • In this study of stacked type film chip capacitor, the important parameters are heat-treated temperature, pressure and time. We measured the temperature dependence of dielectric properties and dissipation factor and the frequency dependence of dielectric properties, dissipation factor, ESR(Equivalent Series Resistance) and impedance in stacked type film capacitor. As a result, the best conditions of heat-treated temperature, pressure and time were proved to be 130$^{\circ}C$, 10kg/$\textrm{cm}^2$ and 3hrs, respectively.

Electrical Properties and Temperature Effects of PET Films with Interface Layers

  • Dong-Shick kim;Lee, Kwan-Woo;Park, Dae-Hee;Lee, Jong-Bok;Seun Hwangbo
    • Transactions on Electrical and Electronic Materials
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    • 제1권4호
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    • pp.25-29
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    • 2000
  • In this paper, PET(Ployethylene Terephthalate) films with semiconducting and interface layers were investigated, The electrical properties, such as volume resistivity, tan$\delta$(dissipation factor) and breakdown strength at various temperatures were measured. Thermal analysis of PET and semiconducting films were measured and compared by differential scanning calorimeter(DSC) of each film. It is found that the volume resistivity of films(dependence on semiconducting interface layers)and electrical properties of PET films are changed ,Breakdown strength and dissipation factor of PET films with semiconducting layer (PET/S/PET) are decreased more greatly than PET and PET/PET films, due to the increase of charge density of charges at two contacted interfaces between PET and semiconductor, The dissipation factor of each films in increased with temperature,. For PET/S/PET film, is depended on temperature more than PET of PET/PET. However, the breakdown strength is increased up to 85$\^{C}$ and then decreased over 100$\^{C}$The electrical properties of PET films with semiconducting/interface layer are worse than without it It is due to a result of temperature dependency, which deeply affects thermal resistance property of PET film more than semiconducting/interface layers.

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Analysis of wave motion in micropolar transversely isotropic thermoelastic half space without energy dissipation

  • Kumar, Rajneesh;Gupta, Rajani Rani
    • Interaction and multiscale mechanics
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    • 제3권2호
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    • pp.145-156
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    • 2010
  • The propagation of waves in a micropolar transversely isotropic half space in the theory of thermoelasticity without energy dissipation are discussed. After developing the solution, the phase velocities and attenuation quality factor has been obtained. The expressions for amplitudes of stresses, displacements, microrotation and temperature distribution have been derived and computed numerically. The numerical results have been plotted graphically.

일부 전류분류영역을 가짐으로서 최소 열손실을 갖는 초전도 전류도입선 (Minimum Heat Dissipation of HTS Current Lead Having Partial Current Sharing Region)

  • 설승윤;허광수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집B
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    • pp.131-136
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    • 2001
  • In this paper, a high-temperature superconductor(HTS) current lead operating in current sharing mode is described. The minimum heat dissipation and the optimum safety factor(cross-sectional area) is obtained analytically for partial current sharing HTS leads. It is assumed that the current lead is in conduction cooled state, and the sheath material is the alloy of silver and gold. The reduced cross-sectional area results partial current sharing state, and consequently reduces conduction heat transfer, but the Joule heat generation is increased. The optimized HTS current lead is different from the conventional copper leads. In the copper leads, the minimum heat dissipation is obtained for the zero gradient of temperature at warm end. However, the temperature gradient at warm end is not zero when the HTS lead operates at minimum dissipation state.

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