• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.995-999
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• 2007

We investigated the characteristics of a flux-lock type superconducting fault current limiter(SFCL) considering magnetization characteristic of iron core. The flux-lock type SFCL, like other types of SFCLs using the iron core, undergoes the saturation of the iron core during the initial fault time. Therefore, if the design to prevent the saturation of the iron core is considered, the effective fault current limiting operation can be achieved. Through the analysis for its equivalent circuit including the magnetization characteristic of the iron core, the limiting impedance of the flux-lock type SFCL was drawn. The magnetization currents and the limited currents of SFCL, which were dependent on the winding direction and the turns' ratio between two coils, were investigated from the short circuit experiment. It was confirmed that their experimental results agreed with the analysis ones.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• pp.511-514
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• 2002

In this paper, we compared the characteristic of fault current liminting in the magnetic shielding type High-Tc superconducting fault current limiter(FCL) using both Piecewise linear magnetization curve and real magnetization one of iron core. From this paper, the characteristics of fault current limiting in both cases showed many differences. The latter has higher fault current than the former, because the saturation of iron core was reflected and more accumulated during fault. It is expected that the more exact characteristic of magnetic shielding type High-Tc superconducting FCL was obtained in the case of design and modeling.

• Proceedings of the KIEE Conference
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• pp.15-17
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• 2002

In this paper, we analyse the dynamic characteristic of 3-phase line start permanent magnet motor considering magnetization. Magnetization vector of NdFeB is obtained from the 2-D FEM magnetization analysis. And comparing the proposed analysis with conventional analysis method, we know that it is necessary to consider magnetization in dynamic analysis.

• Journal of Magnetics
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• v.4 no.1
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• pp.26-32
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• 1999

The HDDR process can be used as an effective means of processing of the coercive Nd-Fe-B-type or the Sm2Fe17Nx materials. The HDDR (hydrogenation, disproportionation, desorption, recombination) processed materials are feartured with a very fine microstructure. The thermomagnetic characteristics of the Nd-Fe-B-type or the Sm2Fe17Nx materials with fine microstructure due to the HDDR process were investigated. It has been found that the fine-microstructured hard magnetic materials showed an unusual TMA (Thermomagnetic analysis) tracting featured with a low and constant magnetization at lower temperature range and a peak just below their Curie temperatures when a low external field is applied. This thermomagnetic characteristic was immediate particularly in the TMA with a low applied field. This thermomagnetic characteristic was interpreted in terms of the competition between two counteracting effects; the decrease in magnetication due to the thermal agitation at an elevated temperature and the increase in magnetization resulting from the rotation of magnetization of the fine grains comparable to a critical single domain size due to the decreased magnetocrystalline anisotropy at an elevated temperature.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.427-433
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• 2003

Permanent magnet movers with three different magnetization patterns were applied to a linear eddy current braking system. By using a two-dimensional analytical technique, this paper deals with the comparison of the design guidelines, magnetic field, required magnet volume, and force capability for three types of linear brakes. The analytical results are also verified by finite element analyses.

• Journal of Magnetics
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• v.10 no.4
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• pp.157-162
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• 2005

We report the magnetic-field dependence of the irreversible magnetization of binary superconductor $MgB_2$. For the temperature region of $T\;<\;0.9T_c$, the contribution of the bulk pinning to the magnetization overwhelms that of the surface pinning. This was evident from the fact that the magnetization curves, M(H), were well described by the critical-state model without considering the reversible magnetization and the surface pinning effect. It was also found that the M(H) curves at various temperatures scaled when the field and the magnetization were normalized by the characteristic caling factors H$\ast$(T) and M$\ast$(T), respectively. This feature suggests that the pinning mechanism determining the hysteresis in M(H) is unique below $T\;=\;T_c$.

• Proceedings of the KIEE Conference
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• pp.38-40
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• 2008

Distribution of Permanent magnet used in the spindle motor on the ODD is arranged by magnetizer. In general, permanent magnet is putted between yoke and back yoke of magnetizer so that symmetric magnetization distribution. But the magnet has unsymmetric magnetization distribution because of eccentricity of the yoke in mass production. So, in this paper we discuss the effect of asymmetric magnetization distribution on back EMF and cogging torque of the spindle motor.

• Proceedings of the KIEE Conference
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• pp.65-67
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• 2004

In this paper, we Present two-dimensional (2-D) analytical model for predicting the magnetic field characteristic of slotless permanent magnet bushless motors. Results from the model are compared to those deduced from 2-D finite element analyses(FEA). It is shown that the radial magnetization and the parallel magnetization of permanent magnet can have flux density on coil, airgap and permanent magnet's surface.

• Proceedings of the KIEE Conference
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• pp.806_807
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• 2009

This paper deals with characteristic analysis on the Linear Switched Reluctance Motor with Interior Permanent Magnet (LSRM-IPM) according to the magnetization of permanent magnet. The governing equations and force equations are derived using analytical method for the suggested models. This paper compares the force characteristics in terms of three cases considering the position and size of permanent magnet.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• pp.46-49
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• 2002

The ac loss is an important issue in the design of superconducting cables and transformers. In these devices the Bi-2223 tapes are usually placed face-to-face In such arrangements ac loss is influenced by adjacent tapes. The effect is investigated by measuring the magnetization loss in the stacked conductor, which consists of various numbers of Bi-2223 tapes. For the stacked conductor in perpendicular field the magnetization loss at low fields is greatly decreased, compared to the loss of the single tape. The loss at high fields is unaffected. This behavior is well described by the slab model.