• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.234-238
• /
• 2003

Ultra small optical drive or PCMCIA type needs a focusing actuator because or applying Blue Laser and enhancing compatibility according to disk physical specification. Based on this need, this paper presents a novel focusing actuator adapted for ultra small optical drive of PCMCIA type. The focusing actuator using Lorenz force generated consists of coil, magnets and plate springs of pivoting. The design issues of the focusing actuator are the flexibility to focus direction, the rigidity to track direction and the higher natural mode of the moving part. For settling these Issues, this paper present mechanical design, computer simulations and test results of the realized focusing actuator. Finally, suitability and usefulness of the focusing actuator was demonstrated by the comparison of simulations and test results in a view of the possibility adapted for ultra small optical drive.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.214-219
• /
• 2003

Recently, the optical disk drive that is thin in thickness has been demanded by the popularization of notebook PC. The device that controls the thickness of a drive is the height of optical pickup. Therefore, researches about this are going on and an asymmetric actuator is the good choice fur this target. However, the actuator of this design has troubles that a subsidiary resonance is likely to be actuated by discord between the center of force and the mass of renter. In this paper, relation between the tracking coil and the subsidiary resonance is analyzed and dynamic characteristics of an actuator are improved by using experiments design and response surface method.

• Journal of Magnetics
• /
• 제18권2호
• /
• pp.105-110
• /
• 2013

The design model and key parameters of the material design for the control of induced magnetic flux at the near-field and efficient power transfer in a modified wireless power transfer (WPT) system with a large air gap of wireless electric vehicles were investigated through analytical simulations for magnetic vector and time-domain transient analysis. Higher saturation magnetic core with low core loss induced a stronger vertical magnetic field by the W-type primary coil in the WPT system with a gap of 20 cm at 20 kHz, which is shown from the vector potentials of the magnetic induction. The transient analysis shows that the higher magnetic fluxes through the pick-up cores lead to a linear increment of the alternating voltage with a sinusoidal waveform in the non-contact energy transfer system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제52권7호
• /
• pp.320-326
• /
• 2003

Slotless Permanent Magnet Linear Synchronous Motor (PMLSM) has good control ability but thrust density is low. So, this paper proposes inserted core type of slotless PMLSM to improve its thrust density. Inserting the core between windings of each phase, detent force is generated by the difference of magnetic resistance in an air gap. To minimize detent force, this paper applies the neural network to inserted core type of slotless PMLSM. The, Magnetic pole ratio, the width of the inserted core and the width of the coil are selected as a design parameter to minimize detent force. In comparison with inserted core type one, thrust ripple greatly decreases by minimizing detent force and also thrust increases in this optimal model.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.404-406
• /
• 2001

This paper is about designing the magnetizing system which is used for magnetizing the NdFeB magnet in a squirrel cage rotor. It propose the shape of the magnetizing yoke, the number of coil turn and the capacitor discharging circuit parameter. In case of magnetizing the NdFeB magnet assembled with a squirrel cage rotor, the eddy current which is produced during magnetizing becomes a disturbance in magnetizing NdFeB magnet. Hence in this paper, we try to design optimized magnetizing system with eddy current considered by FEM(Finite Element Method).

• 한국전기전자재료학회논문지
• /
• 제16권12S호
• /
• pp.1299-1304
• /
• 2003

Fault current limiters (FCL) are extensively needed to suppress fault currents, especially for trunk power systems heavily connected to high voltage/large current transmission lines. Due to its ideal electrical behavior, high-temperature superconductor fault current limiter (HTSFCL) becomes one of the most important developing trends of limiters in power system. This paper describes the result of an investigation of the dielectric characteristics of turn-to-turn insulation for pancake and solenoid type reactor coil in liquid nitrogen. The influence of thickness in a variety length, on AC, DC and impulse surface flashover has been investigated. Also, the relationships between the number of turn and breakdown characteristics were clarified. The information gathered in this test series should be helpful in the design of liquid nitrogen filled DC reactor type HTSFCL.

• 한국자기학회지
• /
• 제19권6호
• /
• pp.222-226
• /
• 2009

기존의 평판형 전자기 엑츄에이터에 쇼티드 턴을 적용한 새로운 형태의 평판형 전자기 엑츄에이터를 제안하였다. 기존의 평판형 전자기 엑츄에이터에서 발생하는 인덕턴스에 의한 초기응답 지연현상을 줄이기 위해 본 논문에서는 기존의 엑츄에이터의 요크와 요크 사이에 중간요크(center yoke)를 추가하고, 쇼티드 턴을 적용한 새로운 형태의 평판형 전자기 엑츄에이터를 제안 하고, 상용 자기장 해석 프로그램인 MAXWELL을 이용한 시뮬레이션을 통해 동적 성능 향상을 검증 하였다.

• Elastomers and Composites
• /
• 제51권4호
• /
• pp.280-285
• /
• 2016

The purpose of this study is to get optimum design and operation conditions of the heating rubber roller for laminating process. The cause of performance degradation of heating rubber roller is delamination of rubber on metal tube, rubber aging due to high temperature. We measured the material properties of thermal expansion, thermal conductivity, specific heat and density and analyzed thermal distributions of rubber layer using finite element method. As a result of heat/flow analysis, the density distribution of heating coil must shorten the stabilization time by reducing the temperature deviation on the length direction at the temperature rising section after increasing the density of the area contacting with the laminate film at the center part which is an opposite of the current composition while enabling to maintain the temperature of heater to be consistent while maintaining the temperature deviation to be low when heat loss is created. Finally, we determined optimum heating method of heating rubber roller.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 C
• /
• pp.1431-1434
• /
• 1994

The annular induction electromagnetic pump with maximum flowrate of $60{\ell}/min$ for the sodium coolant system of liquid metal fast breeder reacters has been designed using the equivalent circuit method. The final optimum values of geometrical and electromagnetic parameters were obtained for an annular induction pump from the relation of the electrical variables giving the developing force to the fluid and the pressure drops between both sides of the pump. The physical properties of the core, coil condoctor materials in the high temperature and pump cooling systems under operation have been taken into account in the design of the pump. The structural material were also selected considering the reaction with sodium and the magnetic field distortion.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1993년도 춘계학술대회
• /
• pp.45-48
• /
• 1993

High-order field gradients are useful for spatial localization of a volume of interest and dynamic range improvement of signal detection in NMR (Nuclear Magnetic Resonance) spectroscopy and imaging. This paper proposes a design method of shielded high-order gradient coils to reduce tile effect of eddy current on tile spectroscopy and imaging results. According to the experimental results, the shielded gradient coils produce less than 2 % eddy current compared to non-shielded coils. Two shielded $z^2$ gradient coils have been designed and constructed for 1.5 T whole-body and 3.0 T animal NMR imaging systems. Experimental results are in good agreement with the theoretically expected behavior and show the utility of the shielded high-order gradient coils.