• Title, Summary, Keyword: High Speed

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Application and Market of High-Speed Electrical Machines

  • Kang, Do-Hyun;Larisa, Strete
    • 제어로봇시스템학회:학술대회논문집
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    • pp.616-620
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    • 2005
  • The technology of high-speed electrical machines is particularly relevant to applications involving electrical power generation and high-speed motors with high power density and high efficiency. Due to the development of improved materials for electrical machines, power electronic elements and design technology, the high-speed electrical machines are being rapidly introduced into industrial applications. The introduction of high-speed electrical machines has created a new market for electrical machines and will, as an application, contribute to the development of modern electrical machines. This paper deals with applications and market trends and KERI's activities in high-speed electrical machines.

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Effect of the Introduction of High-speed Trains on Consumer Welfare

  • BAEK, JISUN
    • KDI Journal of Economic Policy
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    • v.38 no.1
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    • pp.23-52
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    • 2016
  • This paper examines the impact of introducing high-speed trains on consumer welfare, taking the ensuing changes in train schedules into account. Based on the estimated demand model for travel which incorporates consumer's heterogeneous preferences for travel schedules into the standard discrete-choice model, I separately evaluate the impact from adding high-speed trains and that from changes in train schedules. The results indicate that consumers who travel between two cities connected by high-speed trains benefit from the introduction of high-speed trains, while some travelers whose choice set does not include high-speed trains face a reduced frequency of non-high-speed trains, resulting in significant losses.

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Quality of Fresh Vegetable and Fruit Juice produced with Low-Speed and High-Speed Juicers (저속 압착 방식의 착즙기와 고속 파쇄 방식의 블랜더를 사용한 주스의 품질 변화에 대한 연구)

  • Kim, Youngsung
    • The Korean Journal of Food And Nutrition
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    • v.30 no.3
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    • pp.568-577
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    • 2017
  • Vegetables and fruits contain a great deal of vitamins, minerals, dietary fiber and phytochemicals. Therefore, healthconcious consumer prefer beverage made from fresh fruits and vegetables due to their health benefits. This study was conducted to investigate differences in nutritional composition and sensory characteristics of juices depending on the apparatus used: either a low-speed juicer or high-speed blender. All ingredients could be made into juice without addition of water using the low speed juicer. However, addition of water was necessary to produce juice with the high-speed blender. Phenol and flavonoid content, were higher in juice made with the low-speed juicer than that produced with the high-speed blender and were correlated with DPPH radical scavenging ability. Protease activity of pineapples juices was not significantly different for the two methods, but protease activity of kiwi juice was about 8 times higher in juice made with low-speed juicer than that made with the high-speed blender. SOD activity also tended to be higher in the juice made with low-speed juicer. The concentration of dissolved oxygen in the juice made with high-speed blender was higher than that of juice made with a low-speed juicer and was correlated with color change. In addition, the high-speed blender caused an increase juice temperature, but temperature was not changed during use of the low-speed juicer. The noise level of the low-speed juicer was low, but the high-speed blender had high noise intensity comparable to that of railway or aircraft noise. In the sensory evaluation of juice, juice made with the low-speed juicer was preferred over juice made with the high-speed blender. As a result, the overall quality of the juice produced using the low-speed juicer was superior.

A Study on Appropriate Driving Speed for High-Speed Trains Running the Conventional Line (기존선을 통과하는 고속차량의 적절한 주행속도에 관한 연구)

  • Ham, Young Sam
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.9
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    • pp.773-776
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    • 2014
  • KTX (Korea Train eXpress) is the first high-speed train operated in Korea and its highest speed reaches 300 km/h. Korean high-speed trains are mostly operated on the railroads exclusively designed for high-speed trains, but the sections of Seoul~Gwangmyeong, nearby of Daejeon station and Dongdaegu are operated on the existing tracks having the speed less than 150 km/h. With this paper, we'd like to analyze the lateral force that occurs between the wheels and the rail when high-speed trains were operated on the existing track section to suggest an appropriate driving speed for high-speed trains. As the rigid wheel base of the high-speed train is 3m which is about 50% longer than normal vehicles, it works as an advantage for high-speed driving. However, as the lateral force becomes higher than normal vehicles when driving on curves, plans to reduce wear-outs on the wheels are required.

A Study on the Starter Control of the Turbo Generator (터보 제너레이터의 시동기 제어에 관한 연구)

  • 박승엽;노민식
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.3
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    • pp.286-293
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    • 2004
  • This paper presents the result of a study on the starter control for a turbo generator. Because a starter in gear box type turbo-generator system is composed of gearbox and brush DC motor, it should be replaced with High Speed Generator(HSG)) in HSG type Turbo-generator. There-ore, it is necessary to design a new starting algorithm and starter. In gearbox type system, brush DC motor is rotated to the designed speed using low voltage-high current battery power. After brush DC motor speed is increased to several times by gearbox, gas turbine engine can be rotated to designed starting speed. If we implement a starter with High Speed Generator(HSG), it is necessary to drive high-speed generator to high-speed motor. High-speed generator with permanent magnet on rotor has a low leakage inductance fur driving high-speed rotation, and it is necessary high DC link voltage for inverter when High-speed generator is driven to high speed. This paper presents result of development of the boost converter for converting high voltage DC from low battery voltage and design of the inverter for controlling a high frequency current to be injected to motor winding. Also, we show performance of the designed starter by driving the turbo generator.

The Study for Speed-up of Main Line by High Speed Train (기존선의 고속전철 연계운용으로 고속화 방안)

  • 박광복
    • Proceedings of the KSR Conference
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    • pp.105-113
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    • 2001
  • This report was studied about speed-up for main line of KNR(Korea National Railroad) by High Speed Train. The maximum speed of Kyun-Pu line was recorded a 140km/h by Saemaul train in 1985 and the average speed its is a 107km/h now. For operation KTX Kyun-Pu High Speed Train and G7 Korea High Speed Train in KNR line, this report was studied about operation status of High Speed Train in advanced countries, operation situation of train in KNR line and plan of speed-up for main line.

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A Study on the Evaluation on High-speed Machining Characteristics of AL7075 (AL7075의 고속가공특성 평가)

  • 이종현;이동주;이응숙;신보성
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.220-224
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    • 2001
  • High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and molds. To perform efficient high-speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force. To measure cutting force in high-speed machining, dynamometer has to have high natural frequency. In this paper, The dynamometer which has high natural frequency used to measure the cutting force in various cutting conditions. High-speed machining characteristics are evaluated by the cutting force, FFT analysis of the cutting force and chip formation.

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A Study about an estimate about machining accuracy of High Speed Machining (고속가공 가공 정밀도 예측에 관한 연구)

  • 이춘만;류승표;정원지;정종윤;고태조
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.460-465
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    • 2003
  • High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages fur the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining and an estimate about machining accuracy of high-speed machining.

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Development of High Speed Machining Technology(2) (고속절삭가공기술개발(2))

  • 이춘만;류승표;정원지;정종윤;고태조
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.106-112
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    • 2003
  • High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining and an estimate about machining accuracy of high-speed machining.

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Overview and Implication of Technical Trend of New High-speed Train in the World (세계 고속열차 기술개발 동향과 시사점)

  • Park, Choon-Soo;Kim, Ki-Whan;Kim, Sang-Soo
    • Proceedings of the KSR Conference
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    • pp.862-867
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    • 2008
  • High-speed railway is important transportation in the world because it is very comfortable, environmental benefits, energy savings, etc. The increase of demand for high-speed railway influence to develop of new hish-speed trains. Many countries introduced new high-speed train in the market. It meets to the market's needs. They adopt new technology and systems like that active suspension, synchronous permanent magnetic motor, distributed drive system, aero acoustics, etc. In Korea, the project for R&D of new high-speed train is launched last year. We need analysis of technical trend of new high-speed trains in the world. This paper presents a overview of technical trend of new high speed trains and what is key issues in development of high-speed train. It is very useful to develop a next generation high-speed train in Korea.

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