• Proceedings of the Korean Magnestics Society Conference
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• 1992.10a
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• pp.28-29
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• 1992

• Proceedings of the Korean Magnestics Society Conference
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• 2012.05a
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• pp.123-124
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• 2012

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.137.2-137.2
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• 2008

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.27-30
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• 1991

With the recent development of high performance AC superconducting wire of very small ac loss and large current carrying capacity, the possibility of superconducting air core transformer is being studied. The air core transformer has merits of no iron loss, no insulation to the core and no harmonics. But the air core transformer has large exciting current and low magnetic coupling factor. To increase the coupling factor, the transformer of toroidal shape is proposed and designed. (10KVA, 110/220V) Compared with air core transformer of solenoidal shape, the performance is improved. The exciting current occupies about 22% of the rated current.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.36-39
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• 2004

Glass molding is an advantageous method to manufacture glass micro optical components. However, it is difficult to make Tungsten Carbide core for glass microlens array. We have developed novel method to fabricate Tungsten Carbide core for micro glass components using pressure forming. Silicon masters were fabricated by micro machining. Tungsten Carbide core was fabricated by pressure forming and sintering. And we made high quality surface of Tungsten Carbide core by using the magnetic-field-assisted polishing process.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.10
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• pp.511-520
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• 2006

Recently, more attention has been paid to the development of high-speed permanent magnet (PM) synchronous motors, since they are conductive to high efficiency, high power density, small size, and low weight. In high-speed PM machines, core loss and windage loss form a larger proportion of the total losses than usual in conventional mid- or low speed machines. This article deals with the analysis on the core loss and windage loss in PM synchronous motor for high-speed application. Using the data information from a manufacturer and non-linear curve fitting, this paper investigates the magnetic behavior and its core losses in the stator core using the electrical steels. And, the windage loss is calculated according to the variation of the rotational speed, motor inner pressure and temperature.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.45-46
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• 2007

In this paper, we designed the new magnetic properties tester to measure the core loss in high magnetic field strength conditions. The results of measuring showed us the accuracy of new magnetic properties tester which we designed and it could measure in high magnetic field conditions about 1500A/m. The results would provide useful information for applications and successfully applied in the design of electromagnetic fields.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.653-656
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• 2001

This paper describes the design and the analysis of permanent magnetic actuator "Magnetic Switch" using classical method and 2D finite element method. The classical method gives an outline of permanent magnet size and analysis is carried out by finite element method. Therefore we make use of the result in specific detail site of magnet. The transient state is simulated in order to calculate the response time of "Magnetic Switch". The simulation is based upon a step-by-step integration of the electric circuit equations and the tore movement. The contactor uses a permanent magnet for maintaining the closed state. The presented solution takes account of non-linear magnetic material property and spring force controlled by core position. The dynamic response of "Magnetic Switch" is predicted by the simulation agrees closely with the required condition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.29-36
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• 2004

The paper describes recent experimental results on the development of Digital Magnetic Compass (DMC), which can provide smart automatic correction functions to the magnetic interferences. The design methodology of magnetic sensing circuit with ring-core fluxgate sensor is represented. The performance results of the sensing circuits are discussed with error analysis by polynomial regressions. As test results, the sensing circuit filtered only the second harmonic signal that is proportional to the direction of earth's magnetic field, and it leads to the obtainment of bearing information. In addition, the total residual errors of DMC can be analyzed by the adoption of polynomial regressions. It shown that the possibility of high precise DMC, in the future.

• Journal of The Korean Astronomical Society
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• v.42 no.6
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• pp.175-184
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• 2009

A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.