• 제목/요약/키워드: motor RPM

검색결과 450건 처리시간 0.033초

2단 Gifford-McMahon 극저온냉동기의 특성실험 (An Experimental Study of the 2-stage Gifford-McMahon Cryorefrigerator)

  • 박성제;고득용;유창종;김의준;최헌오
    • 설비공학논문집
    • /
    • 제5권3호
    • /
    • pp.198-206
    • /
    • 1993
  • Experimental results of two stage Gifford-McMahon cryorefrigerator are described. In-prototype experiments, drive mechanism is Scotch Yoke type driven by stepping motor, copper meshes and lead balls are used for regenerator's materials in the first stage and the second stage, respectively. To find optimal conditions of the cryopump, no load temperature and refrigeration capacity according to the variation of cycle frequency and operating pressure are measured, and the cool down and load characteristics at particular cycle frequencies are presented. In general, as the cycle frequency is lowered, no load temperature is dropped but refrigeration capacity is diminished. As the representative result, in a case that the cycle frequency is 70rpm and steady state pressure is 14 atm, no load temperature of second stage is lowered to 10.5K in 55 minuters, and in this situation the refrigeration capacity of the first stage is 42W at 80K, that of the second stage is 11 W at 20K.

  • PDF

AUV의 추진성능 추정 기법 연구 (An Estimation Technique for the Thrust Performance of AUVs)

  • 이종무;최현택;문일성;이판묵
    • 한국해양공학회지
    • /
    • 제23권4호
    • /
    • pp.47-51
    • /
    • 2009
  • Thrust is one of the important performance characteristics of an AUV. At the design stage, the resistance of an AUV at its maximum speed is estimated and then the thrust system is designed, including the propeller diameter, propeller rpm, driving system, and required power. However, it is not possible to be certain that the thrust system has been correctly designed until the AUV is launched and its speed is measured. If data from a propeller open-water test is available, the thrust and torque of the propeller at a certain speed can be estimated. In addition, if the motor's torque characteristics are available, the maximum speed saturated by the induced propeller torque can be estimated. In this paper, an easy technique for estimating the maximum speed of an AUV will be shown, even in a case where additional resistance is gained from appendages not considered at the design stage. Furthermore, the thrust performance changes by adjusting the diameter of the propeller can be easily investigated.

디젤 예혼합 압축착화 엔진에서 배기가스 재순환과 과급의 영향 (Effect of EGR and Supercharging on the Diesel HCCI Combustion)

  • 박세익;국상훈;배충식;김장헌
    • 한국자동차공학회논문집
    • /
    • 제14권5호
    • /
    • pp.58-64
    • /
    • 2006
  • Homogeneous charge compression ignition(HCCI) combustion is an advanced technique for reducing the hazardous nitrogen oxide(NOx) and particulate matter(PM) in a diesel engine. NOx could be reduced by achieving lean homogeneous mixture resulting in combustion temperature. PM could be also reduced by eliminating fuel-rich zones which exist in conventional diesel combustion. However previous researches have reported that power-output of HCCI engine is limited by the high intensive knock and misfiring. In an attempt to extend the upper load limit for HCCI operation, supercharging in combination with Exhaust Gas Recirculation(EGR) has been applied: supercharging to increase the power density and EGR to control the combustion phase. The test was performed in a single cylinder engine operated at 1200 rpm. Boost pressures of 1.1 and 1.2 bar were applied. High EGR rates up to 45% were supplied. Most of fuel was injected at early timing to make homogeneous mixture. Small amount of fuel injection was followed near TDC to assist ignition. Results showed increasing boost pressure resulted in much higher power-output. Optimal EGR rate influenced by longer ignition delay and charge dilution simultaneously was observed.

고효율 태양광 모듈 제작을 위한 스트링 공정 최적화 (Shingled String for the High Performance Photovoltaic Module)

  • 지홍섭;문대한;송진호;정채환
    • Current Photovoltaic Research
    • /
    • 제6권4호
    • /
    • pp.119-123
    • /
    • 2018
  • The High Performance Module With The Shingled String Has Several Advantages Such As The Larger Active Area, Higher Open-Circuit Voltage And Smaller Cell To Module (Ctm) Loss. To Obtain Increase Of Power In Pv Shingled Module, The Detailed Condition Of Various Parameters Related To Cutting And Bonding Process Were Investigated In This Study. We Searched The Optimized Cutting Conditions Of Laser Scan Speed, The Number Of Laser-Scribing And Also Bonding Conditions Of Electrically Conductive Adhesives (Eca) By Varying Amount Of Eca, Curing Time And Curing Temperature. The Shingled Pv Module Showed 25.4W of Maxmimum Power At 60 Rpm Of Dipensing Motor Speed, 30 Seconds Of Curing Time And $140^{\circ}C$ Of Curing Temperature, Respectively.

고속 공기 스핀들 설계를 위한 근사해석과 회전체동역학의 비교 (Comparison of Approximation and Rotordynamics Solutions for Design of a High Speed Air Spindle)

  • 이재혁;박상신
    • Tribology and Lubricants
    • /
    • 제35권5호
    • /
    • pp.310-316
    • /
    • 2019
  • This paper presents two methods for designing a high-speed air spindle operated over the rotational speed of 50,000 rpm. The first method is an approximate method, which assumes a symmetric spindle shape even though it is not symmetric in reality. The second is an analysis of rotordynamics using beam and solid models. The approximate method can be used to calculate the bearing load capacities, stiffness and damping coefficients, stability of the shaft system, and response of the forced excitation from the unbalanced mass. Designers can use this method to determine the dimensions of the desired spindle at the first stage of the design. The more detailed behavior of the spindle can be calculated using the rotordynamics theory using beam and solid models based on the Finite Element Method. In this paper, a spindle, with two air bearings, one motor at the end, and two air thrust bearings, is newly developed. The solutions from the two rotordynamics theories are compared with the solution obtained using the approximate method. The three calculations are in agreement, and the procedure for the design of a spindle system, supported on the externally pressurized air bearings, ispresented and discussed.

하천 측량용 헥사콥터의 단일로터에 대한 제자리 비행 성능 연구 (Study on the Hovering Flight Performance of a Single Rotor on a River Surveillance Hexacopter)

  • 정원훈;김봉환;민경무;차앨리;박근우
    • 한국기계가공학회지
    • /
    • 제21권8호
    • /
    • pp.53-59
    • /
    • 2022
  • In this study, an experimental device was fabricated to evaluate the hovering flight performance of a single rotor on a hexacopter used for river surveillance, and a thrust performance test was conducted. In addition, the 3D profile of the propeller was extracted by 3D scanning and CFD analysis was performed using ANSYS CFD 14.5 based on the extracted 3D model of the propeller. The aerodynamic characteristics were compared with the results of the performance tests and CFD analysis, and the vortex structure corresponding to each motor rotational speed in revolutions per minute (rpm) was identified. In the future, we plan to provide valuable data for multicopter propeller design and performance verification.

저소음 청소기 개발 (Low Noise Vacuum Cleaner Design)

  • 주재만;이준화;홍승기;오장근;송화규
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2007년도 추계학술대회논문집
    • /
    • pp.939-942
    • /
    • 2007
  • Vacuum cleaner is a close life product that can remove various dusts from our surroundings. However well vacuum cleaner clean our environments, many people are looking away from it, due to its loud noise. Its noise causes a big trouble in the usual life, for example, catch calls, TV watching and discussing etc. To reduce these inconveniences, noise reduction methods and systematic design of low noise vacuum cleaner are studied in this paper. At first, sound quality investigation is performed to get the noise level and quality that make people TV watching and catch calls available. Based on the European and domestic customer SQ survey result, sound power, peak noise level and target sound spectrum guideline are studied and introduced. As a second, precise product sound spectrums are designed into each part based on the sound quality result. Fan-motor, brush, mainbody, cyclone spectrums are decided to get the final target sound based on the contribution level. Fan-motor is the major noise source of vacuum cleaner. Specially, its peak sound, RPM peak and BPF Peak, cause the people nervous. To reduce these peak sounds, high rotating impeller and diffuser are focused due to its interaction. A lot of experimental and numerical tests, operation points are investigated and optimization of flow path area between diffusers is performed. As a bagless device, cyclones are one of the major noise sources of vacuum cleaner. To reduce its noise, previous research is used and adopted well. Brush is the most difficult part to reduce noise. Its noise sources are all comes from aero-acoustic phenomena. Numerical analysis helps the understanding of flow structure and pattern, and a lot of experimental test are performed to reduce the noise. Gaps between the carpet and brush are optimized and flow paths are re-designed to lower the noise. Reduction is performed with keeping the cleaning efficiency and handling power together and much reduction of noise is acquired. With all above parts, main-body design is studied. To do a systematic design, configuration design developments technique is introduced from airplane design and evolved with each component design. As a first configuration, fan-motor installation position is investigated and 10 configuration ideas are developed and tested. As a second step, reduced size and compressed configuration candidates are tested and evaluated by a lot of major factor. Noise, power, mass production availability, size, flow path are evaluated together. If noise reduction configuration results in other performance degrade, the noise reduction configuration is ineffective. As a third configuration, cyclones are introduced and the size is reduced one more time and fourth, fifth, sixth, seventh configuration are evolved with size and design image with noise and other performance indexes. Finally we can get a overall much noise level reduction configuration. All above investigations are adopted into vacuum cleaner design and final customer satisfaction tests in Europe are performed. 1st grade sound quality and lowest noise level of bagless vacuum cleaner are achieved.

  • PDF

감마선투과검사 장치의 자동 원격조작기 개발 (Development of Automatic Remote Exposure Controller for Gamma Radiography)

  • 주광태;신진성;김동언;송정호;주승환;장홍근
    • 비파괴검사학회지
    • /
    • 제22권5호
    • /
    • pp.490-499
    • /
    • 2002
  • 국내 감마선투과검사용 조사장치는 1,000여대로 2,500여명의 종사자가 대부분 수동으로 원격 조작하는 실정으로 작업의 효율화와 방사선피폭 저감화를 위하여 자동 원격조작기의 사용이 요구된다. 이에 연구팀은 실무에 적합한 토크와 안전계수로부터 $54kgf{\cdot}cm$의 출력을 지닌 24V, 200W의 BLDC모터를 이용하여 $0.4{\sim}1.2m/s$ 범위의 선원 이동 속도를 조절할 수 있는 구동장치와 RF 센서로 구동 속도 조절, 광전센서에 의한 선원 위치 및 timer로 노출시간을 제어할 수 있는 무선 원격조작기를 개발하였다. 이와 같이 개발한 자동원격조작기는 AC 와 DC 겸용, 그리고 기존의 수통 원격조작기에 탈착이 가능하여 자동과 수동을 겸용할 수 있는 경제적 이점 등으로 활용도가 클 것으로 기대된다.

승용차용 터보과급기의 저속 영역 마찰 손실 측정 장치 개발 (Development of Friction Loss Measurement Device at Low Speed of Turbocharger in a Passenger Vehicle)

  • 정진은;이상운;전세훈
    • 한국산학기술학회논문지
    • /
    • 제18권1호
    • /
    • pp.585-591
    • /
    • 2017
  • 본 연구에서는 터보과급기의 성능을 저해하는 주요 인자 중 하나인 마찰손실에 대한 연구를 수행하였다. 실제 엔진에서 빈번하게 사용되는 저속 구간에서의 승용차용 터보과급기의 마찰손실 측정 장치를 개발하고, 30,000~90,000rpm의 저속 영역에서 작동하는 터보과급기의 마찰손실을 측정하였다. 플로팅 베어링 타입의 승용차용 터보과급기를 실험 대상으로 선정하였으며, 마찰손실 측정 장치는 구동 모터, 오일 공급 시스템, 커플링으로 구성되었다. 실제 차량의 저속 운전 상황을 모사할 수 있도록 설계, 제작되었고, 회전속도, 오일 온도 및 압력을 실험 변수로 선정하였다. 또한, 마찰손실 측정 장치는 로드셀을 사용하여 발생하는 마찰 토크를 직접 측정하여 마찰손실을 산출하였으며, 마그네틱 커플링을 통해 구동 모터의 동력을 터보과급기 축에 전달하고, 오일 공급 시스템을 오일 온도 및 압력을 조절하였다. 온도 $60^{\circ}C$$90^{\circ}C$, 압력 4bar의 오일을 공급하는 상태에서 터보과급기가 회전수 30,000~90,000rpm으로 작동할 때 터보과급기 회전속도 증가할 때 마찰손실은 증가하며, 대략적으로 과급기 회전속도의 1.4~1.8 지수승에 비례함을 보이고 있다. 또한 오일온도가 $60^{\circ}C$에서 $90^{\circ}C$로 증가할 때 마찰손실은 최소 41%, 최대 63% 감소하였다.

ProTaper Universal에 축적된 내부 응력이 피로 파절에 미치는 영향 (Effect of Internal Stress on Cyclic Fatigue Failure in ProTaper Universal)

  • 조윤성;김진우;조경모;박세희
    • 구강회복응용과학지
    • /
    • 제28권1호
    • /
    • pp.57-66
    • /
    • 2012
  • 본 연구는 ProTaper Universal에 의도적으로 부여한 내부 응력이 피로 파절에 미치는 영향을 평가하였다. 25 mm 길이의 S1, S2, F1, F2, F3, F4 그리고 F5 파일을 내부 응력을 부여하기 위해서 Endo-Training-Bloc (Dentsply Maillefer)에 auto-stop 될 때까지 속도 300 rpm, 토크 1.0 Ncm의 값으로 밀어 넣었다. 부여한 내부 응력의 횟수에 따라 각각 Stress 0 군(대조군), Stress 1 군, Stress 2 군 그리고 Stress 3 군으로 분류하였다. 경사진 유리판을 사용하였고 파일 파절 시간을 측정하였다. 모든 파일에서는 Stress 3 군은 대조군에 비해 Ni-Ti 파일의 파절 시간이 감소하였고 F2와 F3에서 모든 실험군은 대조군에 비해 파절 시간이 감소하였다. F4와 F5에서 Stress 2 군과 Stress 3 군이 대조군에 비해 파절 시간이 감소하였다. ProTaper Universal의 피로 파절은 파일에 축적된 내부 응력에 의해 영향을 받는다.