• 제목/요약/키워드: Force/Torque Analysis

검색결과 417건 처리시간 0.029초

원호형상의 멀티 블레이드를 가진 풍력터빈 설계 (Design for a circular arc shaped multi-blade windmill)

  • 추권철;김동건;윤순현
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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    • pp.390-395
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    • 2004
  • The characteristics of the circular arc shaped multi-blade windmil are investigatedl. The prototypical windmill was tested in the laboratory at wind tunnel speeds of 5.5, 9.4m/s. and the model windmill was also tested in the laboratory, The power and torque coefficients were studied as functions of the blade section, the aspect ratio for blade diameter and windmill radius(M = 0.3, 0.5, 0.7), the number of blades and finally the tip-speed ratio. The analysis of the experimental results for the model windmill showed that there is the highest revolutions per minute(R.P.M) at the circular arc shaped multi-blade windmill having the blade number 10, aspect ratio(M = 0.7). and the results for the prototypical windmill showed that the power coefficient increased to a maximum value and then decreased again with an increase in the tip speed ratio, while the torque coefficient decreased directly with an increase in the tip speed ratio Finally, the experimental results were compared with the Savonius blade. the maximum power coefficient for the arc shaped blade was greater than for the Savonius blade and occured at a lower tip speed ratio.

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평행식 진동탄환 암거 천공기의 연구(III)-견인력, 토크, 동력 및 모멘크에 관한 모형시험- (A Study on Balanced -type Oseillating Mole-Drainer(III)-Model Test for Draft Force, Torque, Power and Moment)

  • 김용환
    • Journal of Biosystems Engineering
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    • 제1권1호
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    • pp.1-6
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    • 1976
  • This paper is the third one of the study on balanced type oscillating mole-drainer, the first one was presented in No 9. Gyeongsang College Report and the second one in Vol. 17, No.4 of the KSAE. In the first part of this study, the characteristics of traction forces between the nonoscillating earth working equipments and oscillating ones was compared. A model of the balanced type oscillating mole-drainer, which composed of a mechanism that may reduce the machine vibration, was designed following the dimensional analysis and similitude technique. The model test was carried out to clarify the balancing mechanism of the oscillating parts and other parts of the machine. In the light of the results from the model tests, a prototype machine was made for experimental purpose. Results from the field test by a reported in the near future. In the second report, the model tests were carried out under the same soil conditions, i.e, . oscillating frequency, running velocity, and oscillating amplitude, etc. It was clear that use of balanced type oscillating model could substantially reduce the vibration of the whole system of the machine, when compared with the nonoscillating type model. In this paper(the third report), results of investigation on the traction force, power requirement, and moment. etc, is presented. Analysis of variance technique was used for analyzing the effect of the frequency, amplitude, and running velocity on the draft force, torque, power requirements, and moments. The results obtained from the model tests are as follows, 1) By practicing a balanced-type oscillating mole-drainer, it was possible to reduce the traction resistance by 55.1-61. 2 percent of traction resistance, however, was 1.75 - 1.95 times greater than the value of resistance which was induced by use of a mole-drainer with single bullet. The resistance of rear shank against soil was considered as a main causing factor of the above results. 2) As the oscillation frequency was increased, the traction resistance was decreased. Considering on the effect of oscillation the greater the amplitude, and the slower the running velocity was, the greater the reduction ratio of traction resistance was. 3) The ratio of the traction resistance of oscillating mole-drainer to that of non-oscillating one could be represented as a function of dimensionless variable (V/$Af$). The results from the tests were well agreed with the reported results from the experim ents on oscillation plow or hoe. 4) By taking a lower value of (V/$Af$), reducing the traction resistance was possible. This fact meant, however, that the efficiency of mole drain practice would be lower. 5) It was experimentally confirmed under the same condition of soil that the variable (R/$rD1^3$) could be represented as a function of a variable($V^2/gD$) when a non\ulcornerocillating mole-drainer was used. 6) When a oscillating mole-drainer was used, the variable(R/$rD_1^{3}$) could be represented as a function of two variables ($v^2/gD_1$) and (V^2/gD_1$). 7) The torque was not affected by a change of frequency. However, a relation of proportionality existed between torque and amplitude, running velocity, and ratio of bullet diameter. When a balanced type oscillating mole-drainer with two bullets was used, torque was increased by 52.8-78. 4 percent and total power requirement was also increased. 8) Total power requirement was increased linearly in accordance with the increasing frequency, 41.96 percent of total power was used for oscillating action. The magnitude of total power requirement was 1. 8-9. 4 times greater than that of a non-oscillating mechanism. In the view point of power requirement, it was not advisable to increase the frequency, amplitude, running velocity, and ratio of bullet diameter at the same time. 9) Only the positive moment occured in the rear shank. Change of the diameter of a rear bullet, could not affect the balancing against the soil resistance. It was necessary for rear bullet to have a large resistance against soil only when the rear bullet was in backward motion. 10) Within an extent of the experimental base, optimum limits for several design factors were A=0.5cm, $f$=22.5Hz, V=O. 05m/sec, and $\lambda$=1.0 By adapting these values traction resistance was reduced by 40 percent and vibration acceleration wa s reduced by 60 percent. Even though the total , power requirements for operating a balanced type oscillation mechanism was greater ~than that of non-oscillating one, using a oscillating mechanism would be more effective. Because a balanced type oscillating mechanism is used, tractive resistance will be reduced and then the lighter . tractive equipment could be used.

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선체 블록내 용접을 위한 새로운 승월 메커니즘 개발 (Development of a New Climbing Mechanism for Inter-Block Welding in Shipbuilding)

  • 정원지;김기정;김성현;박명환;신기수
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.434-437
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    • 2004
  • This paper presents the development of a new climbing mechanism for inter-block welding in Shipbuilding. The climbing mechanism is that it is career type of robot that can pass over block interval for welding of interblock in shipbuilding. The point part of mechanism is that move ballscrew. The Ballscrew`s capacity account and dynamic analysis of leg part are achieved through this paper. Force and torque analysis were achieved by simulation. This can have strong point in side of cost-cutting and welding amount of work than existent method.

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비선형 효과를 고려한 IPM형 전동기의 DQ축 인덕턴스 및 역기전력상수 파라미터 추출 (Parameter Extraction of DQ-Axis Inductance and Back-EMF Constant For IPM Type Motors Based on Nonlinear Finite Element Analysis)

  • 최홍순
    • 전기학회논문지
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    • 제56권3호
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    • pp.519-523
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    • 2007
  • In this paper, we propose a precise parameter extraction of interior permanent magnet (IPM) motors based on finite element analysis. For the calculation of the two-axis inductances Ld and Lq, the slotting effect and cross magnetization due to torque angle are considered. It is examined that back electro-motive force (BEMF) constant is affected by the magnetic saturation in different ways dependent on motor types. Numerical analyses and some measurements are performed for a spoke type and a flux barrier type IPM motors

Dynamic System Analysis of Machine Tool Spindles with Magnet Coupling

  • Kim, Seong-Keol
    • International Journal of Precision Engineering and Manufacturing
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    • 제3권4호
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    • pp.87-93
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    • 2002
  • In this study, basic concepts of magnet were introduced, and dynamic characteristics of magnet coupling were explored. Based on these characteristics, it was proposed how to analyze transverse and torsional vibrations of a spindle system with magnet coupling. Proposed theoretical approaches were applied to a precision power transmission system machined for this study, and the transverse and torsional vibrations were simulated. The force on magnet coupling was shown as a form of nonlinear function of the gap and the eccentricity. Also, the form of torque transmitted by magnet coupling was considered as a sinusoidal function. Main spindle connected to a coupling of a follower part was assumed to be a rigid body. Nonlinear partial differential equation was derived to be as a function of angular displacement. By using the equation, torsional vibration analysis of a spindle system with magnet coupling was performed. Free and forced vibration analyses of a spindle system with magnetic coupling were explored by using FEM.

축방향 자속형 동기전동기의 오버행 효과에 따른 특성해석 (The Characteristic Analysis of Overhang Effect on Axial Flux Synchronous Motor)

  • 이병준;원진국;손동혁;조윤현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.80-82
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    • 2007
  • This paper presents the overhang effects of a novel axial flux permanent magnet (AFPM) machine, which consist of the segmented stator and fractioned slot windings, with one rotor and double stator. In addition, the overhang effect of permanent magnet of the motor has been analyzed quantitatively. The overhang is used to enhance the force density in permanent magnet machine. According to the variation of overhang length, the flux density distribution and torque are quantitatively compared. For these analysis, three dimensional finite element method (3D FEM) has been used in this paper. From the results, the proper overhang length of PM is selected to improve the performance of the AFPM machine.

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Switched Reluctance Motor와 Brushless DC Motor의 공극 변화에 따른 출력 특성 비교 (Analysis of Output Characteristic in accordance with Airgap Variation in Switched Reluctance Motor and Brushless DC Motor)

  • 윤찬호;박금구;이종찬;전연도;이주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 B
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    • pp.843-845
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    • 2001
  • In this paper, we analyze the characteristics of electecromotive force(emf), phase current and torque according to the length of the air gap using 2nd order FEM(Finite Element Method) in Synchronous Reluctance Motor(SRH) and Brushless DC Motor(BLDC) with same volume and size. In the analysis with FEM, we applied the time-step function considering the motor switch in the magnetic vector potential of the unknown node.

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3 자유도 굴착기 부속 시스템의 기구학적 최적 설계와 기구학/동력학 성능 해석 (Kinematic optimal design and analysis of kinematic/dynamic performances of a 3 degree-of-freedom excavator subsystem)

  • 김희국;한동영;이병주
    • 제어로봇시스템학회논문지
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    • 제3권4호
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    • pp.422-434
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    • 1997
  • In this paper, a two-stage kinematic optimal design for a 3 degree of-freedom (DOF) excavator subsystem, which consists of boom, arm and bucket, is performed. The objective of the first stage is to find the optimal parameters of the joint-actuating mechanisms which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the second stage is to find the optimal link parameters which maximize the isotropic characteristic of the excavator subsystem throughout the workspace. It is illustrated that kinematic/dynamic performances of the kinematically optimized excavator subsystem have improved compared to those of original HE280 excavator, with respect to three performance indices such as maximum load handling capacity, maximum velocity capability, and acceleration capability.

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자기등가회로법에 의한 유도전동기 과도상태해석 (An analysis of transient state for induction motor by using the magnetic equivalent circuit method)

  • 정종호;이은웅;조현길;김준호;이화수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.18-20
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    • 2002
  • In this paper, the construction elements of the induction motor was represented by the magnetic tube. The magnetic tube is basis of the magnetic equivalent circuit. The magnetic equivalent circuit method is convenient of complicated analysis of the transient state of the induction motor. Because the method is restriction on only one direction of magnetic flux. Air gap magnetomotive force was calculated by magnetic equivalent circuit method. Starting transient torque and phase current of the induction motor was confirmed by the theoretical calculation and the experiments.

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굴삭기의 기구학적 최적설계와 성능해석 (Kinematic Optimal Design of Excavator with Performance Analysis)

  • 한동영;김희국;이병주
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1994년도 추계학술대회 논문집
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    • pp.617-622
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    • 1994
  • In this paper, we perform a two-stage, kinematic optimal design for 3 degree-of-freedom excavator system which consists of boom, arm, and bucket. The objective of the first stage is to find the optimal joint parameters which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the first stage is to find the optimal link parameters which maximize the isotropic characteristic throughout the workspace. It is illustrated that performances of the optimized excavator are improved compared to those of HE280 excavator, with respect to the described performace index and maximum load handling capacity.

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