• Title/Summary/Keyword: High RPM

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Development of High Speed mid-Mower for Tractor (II) (트랙터용 고속 미드 모어 개발(II))

  • Kim, Sam-Hee;Kim, Hae-Ji
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.5
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    • pp.80-85
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    • 2016
  • In recent years, work to improve the power of a tractor has been in development. This study, using the mid-PTO power of a compact tractor, attempted to develop a high-speed mid-mower by setting the rotation to more than 3,000 RPM designed/manufactured major components of the high speed mid-mower. The performance of high-speed mid-mower was evaluated by the precision of straight bevel gears, and durability, the noise of the gearbox, the gearbox internal temperature, the maximum rotation speed of the mid-mowers, and the grass cutting test. Through the performance test results, the maximum number of revolutions of the mid-mower was measured over 3,000RPM, the gearbox noise and gearbox internal temperature satisfied the performance requirements of a high speed mid-mower.

Phase Changes of Calcium Carbonate by Temperature and RPM in Continuous Crystallizer (연속식 결정화기에서 온도와 교반속도에 의한 탄산칼슘 결정의 형상변화)

  • Shin, Yuonjeong;Han, Hyunkak
    • Korean Chemical Engineering Research
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    • v.57 no.5
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    • pp.666-671
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    • 2019
  • Calcium carbonate involves three phases such as calcite, vaterite, and aragonite. Calcite and aragonite were more thermodynamically stable than vaterite. The synthesis of aragonite crystals by the reaction with sodium carbonate and calcium chloride solutions was investigated focusing on the effect of temperature and rpm in continuous crystallizer. In the batch crystallization test, calcite was synthesized by a relatively low temperature (under $40^{\circ}C$), but aragonite was formed at high temperature. In the continuous process with 100 rpm, no aragonite was found regardless of reaction temperature. But as increasing the stirring rate to 300 rpm and 500 rpm, the ratio of aragonite to calcite increased as increasing the temperature.

The Development of 150HP/ 70,000rpm Super High Speed Motor Driver for Direct Drive Method Turbo Compressor (직접 구동방식의 터보 압축기를 위한 150마력,70,000rpm 초고속 전동기 구동 시스템 개발)

  • 권정혁;변지섭;최종경
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.40 no.1
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    • pp.45-54
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    • 2003
  • Turbo compressor needs high speed rotation of impeller in structure, high rated gearbox and conventional induction motor. This mechanical system increased the moment of inertia and mechanical friction loss. Resently, the study of turbo compressor applied super high speed motor and drive, removing gearbox made its sire small and mechanical friction loss minimum. This paper describes the implementation of the vector control schemes for a variable-speed 131㎾ PMSM(Permanent Magnet Synchronous Motor) drive in super-high speed application.

Fabrication arid Performance Tests of Flywheel Energy Storage System using High Tc Superconducting Bearing (고온초전도체 베어링을 사용하는 에너지 저장용 플라이휠 장치의 제작 및 성능 평가)

  • Lee, Ho-Jin;Kim, Ki-Baik;Koh, Chang-Seop;Lee, Soo-Hoon;Hong, Gye-Won
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.310-314
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    • 1999
  • A prototype of Flywheel Energy Storage System with high Tc superconducting bearings was fabricated and tested to verify its applicability for the energy industry. The moment of inertia of assembled wheel with rotor magnets is about 1.072${\times}$10$^{-1}$ Kg-m$^2$. The wheel was designed to withstand its integrity up to the rotation speed of 20,000 rpm. YBCO bulk superconductors prepared by seed growth method were used as bearing to levitate and stabilize the rotating wheel. High speed rotation of the flywheel without mechanical contact was achieved by using specially designed Halbach type motor. The flywheel system showed very high stability during test operation performed up to the speed of about 10,000rpm. The energy loss measured by free decay test performed between 9,300 rpm and 7,000 rpm was calculated as about 45 W.

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Surface Gas Temperature of Turbine Blade by Hot Gas Stream of Pyro Starter in Operation Condition (파이로 시동기의 고온 가스에 의한 터빈 블레이드의 표면 가스온도 발달과정 해석)

  • Lee, In-Chul;Kim, Jin-Hong;Koo, Ja-Ye;Lee, Sang-Do;Kim, Kui-Soon;Moon, In-Sang;Lee, Soo-Yong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.63-67
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    • 2007
  • The high pressure turbopump carries out supplying the oxidizer in the liquid propulsion rocket in the combustion chamber. Because an LRE requires a very short starting time , the turbine at the turbopump experiences high torque that was produced by the high pressure and the high temperature. The purpose of this study is to evaluate a turbine blade surface temperature profiles at initial starting 0 ${\sim}$ 0.5 sec. Using $Fine^{Tm}$/turbo, three dimensional Baldwin-Lomax turbulence models are used for numerically analysis. The turbine is composed of 108 blades total, but only 7 rotors were considered because of periodic symmetry effect. Because of interaction with a bow shock on the suction surface, the boundary layer separates from suction surface at inner area of turbine blade. The averaged temperature of the turbine blade tip at 1000 rpm is higher than that of 9000 rpm. Especially at 1000 ${\sim}$ 9000 rpm, temperatures increases on the hub side of the turbine blade tip. Moreover at 9000 rpm, the temperatures from the hub to the shroud of the blade tip increase as well.

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Rotordynamic Design and Analysis of the Rotor-Bearing System of a 600HP Gear Driven Turbo-Compressor (600HP급 기어구동형 터보 공기압축기 회전체계의 동역학적 설계 및 해석)

  • 최상규;김영철;권병수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.50-57
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    • 1997
  • A 600HP class high-speed gear driven 3-stage turbo-compressor (IGCC : Integrally Geared Centrifugal Compressor) driven by a 3600 rpm AC induction motor has been designed, of which low speed pinion runs at 35000 rpm and high speed pinion at 50000 rpm nominally. Due to its high speed operation, the system requires very reliable bearing selection and design as well as accurate rotordynamic analysis and prediction of its dynamic behavior to secure the operating reliability. Rotordaynamic analyses of the IGCC rotor-bearing system predicted that the low speed pinion rotor mounted on 5-pad tilting pad bearings has two critical speeds before its design speed and high speed pinion rotor only one critical speed, and estimated critical speeds of both pinion shafts are away from the continuous operating speed enough to satisfy the corresponding API requirement. The forced response analysis with API specified maximum allowable unbalances also showed that unbalance responses are small enough for smooth operation of the system.

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The Effect of HHO Gas on the Performance of Industrial Diesel Engine Using Biodiesel Blended Fuel (흡기중의 HHO 가스 첨가가 바이오 디젤 혼합연료를 사용한 산업용 디젤기관의 성능에 미치는 영향)

  • Park, Kweon-Ha;Kim, Ju-Youn;Kim, Chul-Jung;Lee, Eun-June;Son, Kwon;Park, Sung-Hoon
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.8
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    • pp.1022-1027
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    • 2011
  • A diesel engine works in high compression ratio due to injection of diesel fuel after compression of air. Therefore the engine has a high thermal efficiency, while nitrogen oxide is produced a lot in high flame temperature regions. In order to solve the problem this study HHO gas is added into the intake air of the industrial diesel engine. The test conditions are loads of 0%, 50% and 100% and engine speeds of 700 to 1900 rpm. The results show the maximum torque and pressure is increased, fuel consumption, smoke and CO emissions are decreased and NOx emission is remained at same level.