• 제목/요약/키워드: partial heating

검색결과 154건 처리시간 0.021초

공진회로(共振回路)를 이용한 유도가열용(誘導加熱用) 부분순환전류형(部分循環電流形) 사이크로콘버터에 관한 연구(硏究) (A Study of the Partial Circulating Current Type Cycloconverter with a Resonant Circuit for Induction Heating)

  • 김현중;조규민;김영석
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1992년도 하계학술대회 논문집 B
    • /
    • pp.1002-1004
    • /
    • 1992
  • This paper presents a study of the partial circulating current type cycloconverter with a resonant circuit for induction heating. A method of input power factor improvement is proposed. Since the circulating currents flow through the circulating current reactors, the out-put currents are continuous and sinusoid. The proposed cycloconverter can keep the displacement factor at 1.0 by PWM control method regardless of load. The control functions are derived, the operational principles are described and the simulation and experimental results are presented.

  • PDF

고주파 부분방전 측정에 의한 초고압 접속함 신뢰성 평가 기술 (A Evaluation Technique for Reliability of Extra-High Voltage Cable Accessories using High Frequency Partial Discharge Measurement)

  • 신두성;이창영;김충식;전승익;김동욱;박완기
    • 대한전기학회논문지:전기물성ㆍ응용부문C
    • /
    • 제49권3호
    • /
    • pp.186-195
    • /
    • 2000
  • In this paper, partial discharge (PD) measurement was performed to evaluate the quality of the cable joint and termination constructions. The resistive coupling technique for PD detection using resistivity of semiconducting layer of the cable in the accessories, such as joints and terminations. With high frequency PD (HEPD) measurement, an excellent sensitivity below 20pC could be achieved under unshielded condition. The localization of the defects in the accessories could be identified. During heating cycle, PDs were monitored and analyzed. At that time, the PDs were dependent on the temperature of the heating cycle and showed cyclic behaviors, which were attributed to local delamination of the interfaces, between epoxy unit and stress relief cone(SRC) and between SRC and cable, due to the difference of thermal expansion. As a conclusion, HFPD measurement technique was proven to be an effective diagnostic method for qualification of extra high voltage (EHV) cable accessories. With this technique, the optimal design of the components of the accessories could be verified not only in an early stage but also under operating condition. This technique would result in the improvement of the reliability of the EHV cable accessories.

  • PDF

유도가열에 따른 SKH51의 반응고 미세조직 특성 연구 (The Characteristics of Microstructure in the Semi-solid State of SKH51 at High Frequency Induction Heating)

  • 이상용
    • 열처리공학회지
    • /
    • 제25권3호
    • /
    • pp.126-133
    • /
    • 2012
  • Semi-solid forming of the high melting point alloys such as steel is a promising near-net shape forming process for decreasing manufacturing costs and increasing the quality of the final products. This paper presents the microstructure characteristics of SKH51 (high speed tool steel) during heating and holding in the mushy zone between $1233^{\circ}C$ and $1453^{\circ}C$, which has been measured by differential scanning calorimetry (DSC). The results of heating/holding experiments showed that the grain size and the liquid fraction increased gradually with temperature up to $1350^{\circ}C$. The drastic grain growth occurred at heating above $1380^{\circ}C$. The strain-induced melt-activated (SIMA) process has been applied to obtain globular grains in the billet materials. Working by mechanical upsetting and successive heating of SKH51 into the temperatures in the mushy zone resulted in globular grains due to recrystallization and partial melting.

유도 가열용에 사용되어지는 새로운 부분공진형 영전압 스위칭 PWM 고주파 인버터 (New Partial Resonant Zero Voltage Switching PWM High Frequency Inverter using Induction Heating)

  • 정영수;문상필;박한석
    • 전기학회논문지P
    • /
    • 제64권4호
    • /
    • pp.261-266
    • /
    • 2015
  • This paper presents a newly proposed prototype of voltage-fed half-bridge partial resonant zero voltage switching PWM inverter operating at a constant frequency variable power regulation scheme, which is more suitable and acceptable for induction heated(IH) cooking appliances. This application-specific high frequency inverter circuit topology using a new generation specially-designed IGBTs can operate under a principle of a fixed frequency ZVS-PWM strategy. The operating principle of a new partial resonant inverter circuit is described on the basis of its computer-aided simulation analysis, its including steady-state operating characteristics.

섬유의 종류 및 온도가열곡선 변화에 따른 콘크리트의 내화특성 (Fire Resistance of the Concrete Corresponding to the Various Fiber Contents and Heating Curves)

  • 한천구;배장춘
    • 한국건축시공학회지
    • /
    • 제8권5호
    • /
    • pp.101-107
    • /
    • 2008
  • This study investigated fundamental characters of the concrete according to various fiber types and contents and their properties of spatting resistance and residual compressive strength after fire test corresponding to ISO and RABT heating corves. The results were summarized as following. The Flowability was gradually declined as the increase of fiber contents, and it was the most favorable with nylon(NY) fibers. The decrease of air contents due to increasing fiber contents was in order by polypropylene(PP), polyvinyl alcohol(PVA) and NY fibers. The compressive strengths were over 40 MPa at 7 days and 50 MPa at 28 days. It was in order by PVA, PP and NY fibers. For the spatting properties, all specimens were prevented at ISO heating curve. In the other hand, the partial spatting at the surface occurred on the plain without fibers, but it was prevented over 0.10 % of PVA and 0.05 % of PP and NY fibers at the RABT heating curve.

사각공간내에서의 부분바닥가열에 의한 자연대류에 관한 연구 (Natural Convection in a Rectangular Enclosure with Localized Heating from Below)

  • 한화택
    • 설비공학논문집
    • /
    • 제7권2호
    • /
    • pp.287-297
    • /
    • 1995
  • In this study, the geometry consists of a two-dimensional rectangular enclosure with localized heating from below. The size and the location of the heater on the floor has been varied, and one of the vertical walls remains at a low temperature simulating a cold window. The governing equations for momentum, energy and continuity, which are coupled with turbulent equations have been solved using a finite volume method. A low Reynolds number $k-{\varepsilon}$ model has been incorporated to solve the turbulent kinetic energy and the dissipation rate. The heat transfer characteristics and the thermal environmental characteristics of the room have been obtained for various system parameters in a room with a partially heated floor.

  • PDF

졸-겔법에 의한 $ZrO_2$-$SiO_2$계 유리 제조 (Glass Preparation of$ZrO_2$-$SiO_2$ System by the Sol-Gel Method)

  • 신대용;한상목;소명기;이풍헌
    • 한국세라믹학회지
    • /
    • 제27권5호
    • /
    • pp.668-676
    • /
    • 1990
  • Glass in the ZrO2-SiO2 system containing up to 30mol% ZrO2 were prepared by heating the gel made from the mixed solutions of Zr(OC3H7)4 and partial hydrolysed Si(OC2H5)4. As a result, the monolith gel was made from the HCl and water content as 2.7$\times$10-3 and 8 molar ratio to alkoxide and drying temoperature as 4$0^{\circ}C$. Heating rate of dry gel maintained under 0.5$^{\circ}C$/min and heating at a temperature as 90$0^{\circ}C$ was found to be for making the transparent glass.

  • PDF

지열원 히트펌프시스템의 실사용을 통한 난방성능연구 (Heating Performance of a Ground Source Heat Pump System through Actual Operation)

  • 구경민;정영만;황유진;이재근;장세용;김인규;진심원;이동혁
    • 대한설비공학회:학술대회논문집
    • /
    • 대한설비공학회 2008년도 하계학술발표대회 논문집
    • /
    • pp.1341-1346
    • /
    • 2008
  • This paper presents the heating performance of a water-to-refrigerant type ground source heat pump system (GSHP) installed in a school building. The evaluation of the heating performance has been conducted under the actual operating conditions of GSHP system in the winter. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. For analyzing the heating performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the heating capacity and the input power were evaluated for determining the heating performance of the GSHP system. The average heating coefficient of performance (COP) of the heat pump was found to be 5.1 at partial load of 46.9%, while the overall system COP was found to be 4.2.

  • PDF

지열원 히트펌프시스템의 실사용을 통한 난방성능연구 (Heating Performance of a Ground Source Heat Pump System through Actual Operation)

  • 구경민;정영만;황유진;이재근;장세용;김인규;진심원;이동혁
    • 대한설비공학회:학술대회논문집
    • /
    • 대한설비공학회 2008년도 하계학술발표대회 논문집
    • /
    • pp.788-793
    • /
    • 2008
  • This paper presents the heating performance of a water-to-refrigerant type ground source heat pump system (GSHP) installed in a school building. The evaluation of the heating performance has been conducted under the actual operating conditions of GSHP system in the winter. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. For analyzing the heating performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the heating capacity and the input power were evaluated for determining the heating performance of the GSHP system. The average heating coefficient of performance (COP) of the heat pump was found to be 5.1 at partial load of 46.9%, while the overall system COP was found to be 4.2.

  • PDF