• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.721-722
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• 2006

Industrialization and technique consequently in quick development the motor field small size and light weight, high efficiency and highly energy density in necessity. The permanent magnet motor small size and the research regarding the research of the torque and efficiency is coming to be active. From this paper the research regarding the quality permanent magnet motor and analysis and it was developed recently the NdFeB anisotropic bond magnet which is a high magnetic force material use, from the hazard which accomplishes power density it is high permanent magnet motor of small size and light weight it researched. The Finite Element Method it led and motor optimization. Also the experiment and analysis permanent magnet motor it is improved the motor and result it led and different it compared.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.138-144
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• 2000

The detent force caused by the interaction of magnets with the teeth of a armature core deteriorates the driving performance of a permanent magnet linear synchronous motor. In this paper, we analyze the fields and forces of a linear synchronous motor with segmented or skewed magnet arrangement according to lateral overhang length of permanent magnets. For the analysis, the 3-dimensional equivalent magnetic circuit network method is used. The detent force and the static thrust are analyzed according to the segmented or skewed angle and the overhang length of permanent magnets, and the optimal angles that the detent force is minimized are found out in each case. The analysis results are compared with the experimental ones and shown a reasonable agreement.

• Journal of the Korean Magnetic Resonance Society
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• v.23 no.3
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• pp.81-86
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• 2019

Overhauser dynamic nuclear polarization (O-DNP) has been an efficient method to boost the thermal nuclear polarization in liquids at room temperature. However, O-DNP for a benchtop NMR using a permanent magnet has remained unexplored yet. In this work, we report the development of an O-DNP system adopting a permanent magnet of 1.6 T. Q-band (~43 GHz) high-power amplifier produced 6 W microwave for saturation. Instead of resonator, we used an open-type antenna for the microwave irradiation. For several representative small molecules, we measured the concentration and frequency dependences of the enhancement factor. This work paves the way for the development of a benchtop DNP-NMR system overcoming its disadvantage of low quality signal when using a permanent magnet.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.935-943
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• 2015

Permanent magnetic actuators (P.M.A.s) are widely used to drive medium-voltage-class vacuum circuit breakers (V.C.B.s). In this paper, a method for design optimization of a P.M.A. for V.C.B.s is discussed. An optimal design process employing the response surface method (R.S.M.) is proposed. In order to calculate electromagnetic and mechanical dynamic characteristics, an initial P.M.A. model is subjected to numerical analysis using finite element analysis (F.E.A.), which is validated by comparing the calculated dynamic characteristics of the initial P.M.A. model with no-load test results. Using tables of mixed orthogonal arrays and the R.S.M., the initial P.M.A. model is optimized to minimize the weight of the permanent magnet (P.M.) and to improve the dynamic characteristics. Finally, the dynamic characteristics of the optimally designed P.M.A. are compared to those of the initially designed P.M.A.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.481-486
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• 2014

The demand for a DC power distributed system is increasing as renewable energy sources and DC electrical load are proliferating. For the automation of a power system, a magnetic contactor for the DC power system is required. The conventional magnetic contactors are mostly equipped with a solenoid magnetic actuator. However, the conventional magnetic contactor has problems with continuous power consumption, and heat generation. To address these problems, a permanent magnet type DC magnetic contactor is proposed in this paper.

• Journal of Magnetics
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• v.5 no.2
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• pp.59-64
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• 2000

A drum type of high gradient magnetic separator was designed and optimized by computer simulations. The magnetic separator consists of high performance rare earth $(Nd_2Fe_14B)$ permanent magnets and magnetic yokes of extremely low carbon steel interconnecting the permanent magnets. Magnetic circuits of the separator were simulated for the aim of the least cost, highest magnetic strength and most efficient function by using specialized S/W (Vector Field Program) employing the Finite Element Method. The magnetic flux density was provided to be strong enough to collect the invisible fine metal particles from the surface of hot rolled steel plate with the efficiency of almost 95%.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1551-1557
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• 2015

Magnetic coupling is used where required high reliability. because magnetic coupling's durability is stronger than mechanical coupling's durability. This paper shows the characteristics of radially magnetized tubular type magnetic coupling by using Analytical method such as space harmonic method. Analytical method was used, to find force characteristics. First, on the basis of the magnetic vector potential and two-dimensional(2-D) polar-coordinate system, the magnetic field solutions of the radially magnetized permanent magnet are obtained. And we obtain the analytical solutions for the flux density produced by permanent magnet. Finally, we can calculate the force by using the Maxwell stress tensor. And then, Finite element method(FEM) is used to validate force characteristics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.36-43
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• 2019

In this paper, the characteristics of the coaxial magnetic gear according to the shape of the same gear ratio are analyzed using the two - dimensional finite element analysis. The rotor shape is SMCMG, CPCMG and RCMG. After this we analyzed the characteristics according to three shapes. Also, the amount of permanent magnet used in each shape was compared. Next, characteristics analysis of the magnetic gear according to the shape at the same torque was performed. And the total weight and efficiency of the magnetic gears were compared and verified.

• Journal of Institute of Convergence Technology
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• v.12 no.1
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• pp.7-12
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• 2022

The reduction ratio of the magnetic gear is determined by the ratio of the number of poles between the high-speed permanent magnet layer and the low-speed permanent magnet layer. In general, it is known that the greater the least common multiple of both poles, the smaller the torque ripple called by cogging of the magnetic force generated in the magnetic gear. However, little is known about the effect of the harmonic modulator that filters the magnetic field in the magnetic gear to magnetically couple the high-speed side and the low-speed side except for the number of poles. In this study, torque ripple characteristics according to changes in modulator shape such as opening ratio and tooth thickness are analyzed using a finite element analysis tool.

• Design & Manufacturing
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• v.6 no.2
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• pp.48-53
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• 2012

In previous study, it showed that the MAP was greatly effective polishing process for magnesium plate. But it had lower efficiency than magnetic materials such as SM45C. It was very difficult to cut non-magnetic materials using the MAP process because the process was fundamentally possible by help of a magnetic force. This study aimed to verify analytically formation of the magnetic field in a case of the non-magnetic materials especially focused on magnesium plate. So, In this study, the magnetic density flux was predicted using simulation program. As a result, the magnetic density flux was lower at the center of pole on inductor than outside. It had same result on the experimental verification. And magnetic force was lower according to increase of working gap. So, to improve the magnetic force, permanent magnet was installed under the workpiece. In that case, the magnetic density flux not only at center but also at outside of pole was increased. Therefore, the efficiency of magnetic abrasive polishing was also increased. A design of experimental method was adopted for assessment of parameters' effect on the MAP results of magnesium plate for improving the magnetic force.