• 제목/요약/키워드: Line Efficiency

검색결과 2,071건 처리시간 0.036초

차세대 전동차 대불선 시운전 시 유지보수방안 연구 (A study on advanced EMU's maintenance program on test operation in Dabul line)

  • 김영규;박세영;송정훈;안천헌;이한민
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2010년도 춘계학술대회 논문집
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    • pp.2215-2222
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    • 2010
  • Advanced EMU have been enhanced in terms of safe transport and maintainability. It is a new urban railway technology that enables an operation institution to cut repair and maintenance costs and customers to use convenient service at lower costs based on IT technology. If a development vehicle of Advanced EMU is completed, it will be used to test the entire advanced EMU system through sufficient performance check and reliability check prior to operation in commercial line. It will also verify efficiency, safety, punctuality and energy efficiency of transport. Accordingly, it is necessary to figure how to repair and maintain vehicles to enhance safety of Advanced EMU system in cooperation with operation during the period of comprehensive evaluation on the operation of a development vehicle in a test line. In this paper, we investigated the maintenance program of Advanced EMU on test operation in Dabul line. The test condition and operation environment of Advanced EMU in Daebul line was analyzed.

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직립 기동 영구자석 동기전동기의 기동토크 최적화 설계 (Optimal Design for Starting -Torque of Line-Start Permanent Magnet Synchronous Motors)

  • 김병국;문지우;김미정;이병준;조윤현
    • 전기학회논문지
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    • 제56권8호
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    • pp.1390-1396
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    • 2007
  • The line-start permanent magnet synchronous motor has a high efficiency and an advantage in constant speed operation regardless of the effect of load variation. However, it is difficult to predict the performance of characteristics accurately, because of the unbalanced starting torque with the initial starting position of the rotor and the generation of a break torque. In this paper the dynamic characteristics of the line-start permanent magnet synchronous motor are described and compared with those of the squirrel-cage induction motor through the simulation to find the characteristics of the permanent magnets and the rotor bars in the line-start permanent magnet synchronous motor. Finally this paper gives the comparison between the simulation results and the experimental results.

In-line형 세퍼레이터의 기-액 다상유동 특성에 관한 연구 (A Study on the Gas-liquid Multiphase Flow Characteristics of the In-line Type Separator)

  • 한상목;김영주;우남섭;이왕도;조해진
    • 한국산업융합학회 논문집
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    • 제26권5호
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    • pp.803-812
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    • 2023
  • The subsea separator of an offshore plant for offshore oil and gas development performs the process of separating oil and gas from crude oil produced in the subsea. The oil-gas subsea separator can be divided into a gravity type that separates fluids by gravity and an in-line type that separates fluids using centrifugal force of density. In the case of the deep sea, the development of a small in-line type separator is required due to manufacturing cost and safety problems caused by water pressure. Therefore, in this study, the gas-liquid phase separation efficiency of the subsea separator was identified through the study of the multiphase flow characteristics of the in-line type separator. For the optimal design of the in-line type separator, the shape of the internal swirl element(ISE) was selected first, and the separation efficiency results for each section of the in-line type separator were analyzed. This study was conducted in parallel with experiments and numerical analysis, and it is expected that the reliability and efficiency of the in-line type separator will be improved through the results.

수산소 혼합가스를 이용한 선상가열 특성 (The Characteristics of Line Heating Using Hydrox Gas)

  • 김홍건;곽이구
    • 한국생산제조학회지
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    • 제20권4호
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    • pp.407-411
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    • 2011
  • The technology of line heating has evolved in various methods. Among them, fossil fuels like ethylene gas and LPG(Liquid Petroleum Gas) are widely used due to their simple utility. In the meantime, the technology implementing high frequency for line heating has also been developed continually, but its manufacturing technology or application includes lots of problems by now. One of the main characteristics of line heating using conventional technolob'Y is the quenching effect followed by heating process. On the other hand, hydrox gas which is mixed by hydrogen and oxygen is a prominent candidate for an application without above shortcomings. Especially, it is found that line heating using hydrox gas is tremendously effective taking low cost as well as low noise. In this paper, a small cell with high efficiency which can minimize installing space is developed to deal with the problem installing in narrow place. Experiments to prove the validation, efficiency and effectiveness is carried out by characterizing in the line heating of steel. It is found that the energy saving of using hydrox gas for line heating is significant and that the deviation performance is reduced by 78~89%. Furthermore, the noise is also reduced as amount of 18.3% though the heating time is not too different.

상품라인별 가격결정이 적재효율 및 물류비에 미치는 영향에 관한 연구 (Study on the Effect of Product Line Pricing on Loading Efficiency and Logistics Cost)

  • 정성태;윤남수;한규철
    • 유통과학연구
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    • 제12권8호
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    • pp.55-69
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    • 2014
  • Purpose - Despite the importance of price, many companies do not implement pricing policies smoothly, because typical price management strategies insufficiently consider logistics efficiency and an increase in logistics costs due to logistics waste. This study attempts to examine the effect of product line pricing, which corresponds to product mix pricing, on logistics efficiency in the case of manufacturer A, and analyzes how logistics performance changes in response to these variables. Research design, data, and methodology - This study, based on the case of manufacturer A, involved research through understanding the current status, analyses, and then proposing improvement measures. Among all the products of manufacturer A, product group B was selected as the research object, and its distribution channel and line pricing were examined. As a result of simulation, for products with low loading efficiency, improvement measures such as changing the number of bags in the box were suggested, and a quantitative analysis was conducted on how these measures influence logistics costs. The TOPS program was used for the Pallet loading efficiency simulation tool in this study. To prevent products from protruding out of the pallet, the maximum measurement was set as 0.0mm, and loading efficiency was based on the pallet area, and not volume. In other words, its size (length x width) was focused upon, following the purpose of this study and, then, the results were obtained. Results - As a result of the loading efficiency simulation, when the number of bags in the box was changed for 36 products with low average loading efficiency of 73.7%, as shown in

    , loading efficiency improved to 89.9%. Further, from calculating logistics cost based on the cost calculation standard of manufacturer A, the amount of annual logistics cost reduction amounted to 101,458,084 KRW. Given that the sum of the logistics cost of the product group B of manufacturing enterprises A is 400,340,850 KRW, it can be reduced by 25%, to 298,882,766 KRW. Although many methods improve loading efficiency, this study proved that logistics cost could be reduced by changing the number of bags within boxes. If this measure is applied to other items, visible logistics cost reduction effects will be realized through improvements in loading efficiency. Conclusions - Future pricing policies should consider their correlation with quality, loading efficiency, product specifications, and logistics standardization to prevent logistics waste, enabling management to improve earnings for companies. Thus, when companies decide pricing policies for new products, the aspects of merchandising and marketing should take priority; however, the aspect of logistics also needs to be considered as significant. Measures revealed by the study results are not only the responsibilities of manufacturing enterprises. Pricing policy agreements between manufacturing enterprises and distribution companies, and logistics factors related to price determination should be considered; further, governments should also support them for their collaborations. This will enable consumers to purchase quality products with low prices.

  • 친환경 Ultra-capacitor에 의한 순시전압강하의 직렬전압보상 시스템 (Series Voltage Compensation Systems for Voltage Sag by Using an Environmentally Friendly Ultra-capacitor)

    • 손진근;전희종
      • 전기학회논문지
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      • 제58권4호
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      • pp.763-769
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      • 2009
    • A series voltage compensation(SVC) system is a power-electronics controller that can protect sensitive loads from disturbance in the supply system. Especially, voltage sags are considered the dominant disturbances affecting the power quality. This paper dealt with a system of off-line type voltage sag compensation by using a bi-directional DC/DC converter of environmentally friendly ultra-capacitor. This capacitor is attached to the DC link of SVC through the high-efficiency DC/DC converter in order to compensate the DC link voltage drop during short-term power interruption as voltage sags. Therefore, in this paper, a DC/DC converter to control high-efficiency energy of ultra-capacitor and voltage sag detection algorithm of off-line type SVC systems are newly introduced. According to the results of experimental of prototype system, it is verified that the proposed system has effectiveness of voltage sag compensation using an ultra-capacitor.

    단단 천음속 축류압축기 동익의 Stacking Line 설계 최적화 (Optimal Design for Stacking Line of Rotor Blade in a Single-Stage Transonic Axial Compressor)

    • 장춘만;;김광용
      • 한국유체기계학회 논문집
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      • 제9권3호
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      • pp.7-13
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      • 2006
    • Shape optimization of a rotor blade in a single-stage transonic axial compressor has been performed using a response surface method and three-dimensional Navier-Stokes analysis. Two shape variables of the rotor blade, which are used to define a blade skew, are introduced to increase an adiabatic efficiency. Throughout the shape optimization of a rotor blade, the adiabatic efficiency is increased to about 2.2 percent compared to that of the reference shape of the stator. The increase in efficiency for the optimal shape of the rotor is due to the pressure enhancement, which is mainly caused by moving the separation position on the suction surface of rotor blade to the downstream direction.

    효율 향상을 위한 축류 압축기 동익의 스윕, 린, 스큐각의 형상 최적화 (Shape Optimization of Swept, Leaned, and Skewed Blades in a Transonic Axial Compressor for Enhancing Rotor Efficiency)

    • 장춘만;;김광용
      • 유체기계공업학회:학술대회논문집
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      • 유체기계공업학회 2005년도 연구개발 발표회 논문집
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      • pp.525-532
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      • 2005
    • Shape optimization of a transonic axial compressor rotor operating at the design flow condition has been performed using response surface method and three-dimensional Navier-Stokes analysis. Three design variables of blade sweep. lean and skew are introduced to optimize the three-dimensional stacking line of the rotor blade. The object function of the shape optimization is selected as an adiabatic efficiency. Throughout the shape optimization of the rotor. the adiabatic efficiency is increased by reducing the tub comer and tip losses. Separation line due to the interference between a passage shock and surface boundary layer on the blade suction surface is moved downstream for the optimized blade compared to the reference one.

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    압축기용 단상 전동기의 회전자 자계구조 변경에 따른 성능에 관한 연구 (A Study on the Performance Improvement of Rotor Structure Modifications in Single-Phase Motors for Compressor Applications)

    • 정태욱
      • 한국산업융합학회 논문집
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      • 제27권2_2호
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      • pp.325-332
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      • 2024
    • Contemporary power systems demand efficient and sustainable technologies. Single-phase induction motors, while widely used, face efficiency challenges due to inherent rotor losses. Proposed solutions include the Line-start Permanent Magnet Synchronous Motor (LSPMSM), leveraging permanent magnets for enhanced energy density but facing demagnetization and cost issues. Alternatively, the Line-start Synchronous Reluctance Motor (LSRM) operates as a hybrid motor without permanent magnets, reducing rotor losses and potentially improving efficiency. This paper focuses on designing an LSRM rotor for air conditioner compressors, analyzing start-up characteristics and efficiency through finite element analysis. A comparative study with single-phase induction motors provides insights for future motor technology selection, balancing efficiency and other requirements.