• Journal of Magnetics
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• v.18 no.2
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• pp.105-110
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• 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.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.769-770
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• 2006

This paper proposes the design method of a magnetic suspension that can control external vibration caused by low frequencies on the external vibrations by low frequencies. The magnetic suspension with individual controls is able to compensate the vibrations unlike a mechanical suspension. In the magnetic suspension, two characteristics are required. Firstly, magnetic motive force(MMF) by armature winding must be increased linearly. Secondly, identical magnitude of output force should be produced as direction of MMF. In this paper, axis-symmetric finite element analysis is used for magnetic field analysis. In order to optimize magnetic suspension, response surface methodology combined with experimental design is applied to investigate the characteristics and optimize the magnetic suspension for vibration -free table.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.942-948
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• 2011

This paper deals with characteristic analysis of axial flux permanent magnet (AFPM) machines with axially magnetized PM rotor using quasi-3-D analysis modeling. On the basis of magnetic vector potential and a two-dimensional (2-D) polar-coordinate system, the magnetic field solutions due to various PM rotors are obtained. In particular, 3-D problem, that is, the reduction of magnetic fields near outer and inner radius of the PM is solved by introducing a special function for radial position. And then, the analytical solutions for back-emf and torque are also derived from magnetic field solutions. The predictions are shown in good agreement with those obtained from 3-D finite element analyses (FEA). Finally, it can be judged that analytical solutions for electromagnetic quantities presented in this paper are very useful for the AFPM machines in terms of following items : initial design, sensitivity analysis with design parameters, and estimation of control parameters.

• Journal of Magnetics
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• v.22 no.1
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• pp.133-140
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• 2017

Split magnetic fluid sealing is a combination of magnetic fluid rotary and plane sealing. Using the theory of equivalent magnetic circuit design as basis, the author theorized the pressure resistance performance of magnetic fluid plane sealing. To determine the pressure resistance of magnetic fluid plane sealing, the author adopted the method of finite element analysis to calculate the magnetic field intensity in the gap between plane sealing structures. The author also analyzed the effect of different sealing gaps, as well as different ratios between the sealing gap and tooth and solt width, on the sealing performance of split magnetic fluid. Results showed that the wider the sealing gap, the lower the sealing performance. Tooth width strongly affects sealing performance; the sealing performance is best when the ratio between tooth width and sealing gap is 2, whereas the sealing performance is poor when the ratio is over 8. The sealing performance is best when the ratio between the solt width and sealing gap is 4, indicating a slight effect on sealing performance when the ratio between the solt width and sealing gap is higher. Theoretical analysis and simulation results provide reference for the performance evaluation of different sealing equipment and estimation of critical pressure at interface failure.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.871_872
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• 2009

This paper presents study of hysteresis model for magnetic hysteresis analysis by Preisach model. In ferromagnetic material, magnetization is non-linear and varies according to magnetic field which is called B-H curve. As hysteresis phenomenon affect on performance of motor, magnetic hysteresis analysis is essential and needed for designing motor that satisfies specification. Therefore, in this paper, methods for calculating magnetization are presented and discussed.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.83-87
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• 2014

This paper describes the magnetic field analysis of wireless power transfer via magnetic resonant coupling. The wireless power transfer system for supplying power to electric vehicle is developed. The parameters of coil transfer system are simulated by the finite element method (FEM). Therefore the coil structure of power transfer system can be accurately analyzed. This paper deals with 3kW wireless transfer system.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.3
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• pp.59-63
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• 2001

This paper presents a new modeling of the two dimensional magnetic property in soft magnetic materials for the magnetic field computations. In this modeling an approximate treatment is introduced to expand the applicable exciting frequency range. The result shows that the new modeling presented here is very useful in simplicity of magnetic field analysis.

• KSTLE International Journal
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• v.2 no.2
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• pp.114-119
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• 2001

The distribution of magnetic flux density of electro-magnetic chucks may clarify the clamping characteristics, which is strongly related to the machining efficiency and machining accuracy in surface grinding machine. Therefore the distribution of the normal and the tangential components of magnetic flux density have been analyzed theoretically. It appears that the normal component of magnetic flux density increases and the tangential component of magnetic flux density increases as the ratio of the separator width to the pitch, e/p decreases. The results seem to increase the stability and uniformity of normal component of magnetic flux density for the decreased e/p.

• Journal of the Speleological Society of Korea
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• no.81
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• pp.1-5
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• 2007

The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power This method is one of the precision techniques and has an aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are rarely researcher in this feilld because of non-effectiveness of magnetic abrasive. Therefore, in this paper we deals with the development of the magnetic abrasive with the fse of Sr-Ferrite. In this development, abrasive grain A has been made by using the resin bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Sr-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only A abrasive and Sr-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From SEM analysis, we found that A abrasive and Sr-Ferrite were strongly bonding with each other.

• Journal of the Speleological Society of Korea
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• no.70
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• pp.45-50
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• 2006

The magnetic polishing is the useful method to finish using magnetic power of magnet. This method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe for transportation. The magnetic abrasive polishing method is not so common for machine that it is not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper deals with development of the magnetic abrasive using worthless mineral. In this development, abrasive grain WA and GC used to resin bond fabricated low temperature. And magnetic material was fabricated from the worthless mineral which were closed into 200 mesh grit type. The XRD analysis result show that only WA and GC abrasive and worthless mineral crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it is found that WA and GC abrasive and worthless mineral were strong bonding with each other by bond.