• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.12-19
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• 1998

This paper deals with ACSR(Aluminum Conductor Steel Reinforced) inner corrosion detection using a detector which automatically runs on an ACSR distribution line and inspects the inner corrosion of the conductor by utilization of the nondestructive eddy current test. According to corrosion appearance and development of ACSR, the impedance change of the eddy current coils is theoretically verified. And then specifications and performances of the detector are described. Experimental procedures and desirable test results are reported. In conclusion, this detector can realize the nondestructive detecting of an ACSR inner corrosion. Upgrading the maintenance efficiency and improving the reliability of distribution line, whether is covered with insulating materials or not, would be expected by this nondestructive test method.method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.50-56
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• 2012

The Multi D.O.F spherical motor can drive rotating as well as tilting three degree of freedom with one motor. Existing three degree of freedom to drive with three motors that are connected by gears and belts, that will be too large size and big loss at gears and belts. So Reducing system size and improving efficient is using the Multi D.O.F spherical motor in three degree of freedom systems. For this reason, efficiency of Multi D.O.F spherical motor is one of the important performance indiccators. In this paper presented that how to improve the efficiency of the Multi D.O.F spherical motor. The fist of method is using the stator iron core's material with high permeability and resistivity for reducing the eddy current loss. However, it was the disadvatages of motor-making and economic. So author propose the resonable method of reducing the eddy current loss in the stator iron core. That is using the rotor with double-air gap.

• 전기의세계
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• v.29 no.9
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• pp.594-598
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• 1980

This paper describes an analytical method on the starting torque of hysteresis motor, taking account of penetration effects of magnetic-field and eddy-current into the rotor, to the elliptical approximation method of hysteresis-loop. By the above method, it have obtained the torque of rotor ring with non-magnetic and non-conductive material arbor, and the results are concerned and compared with that of computed by aid of callibration factor, k=1+exp(-2t$_{r}$/.delta.).)

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.22-24
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• 1998

The current distribution in the source coil region is analyzed using the two dimensional finite element method. The variables in the FEM are the magnetic vector potentials and the source current density. The boundary condition for the source current density is that the total current is the sum of the eddy current and the source current and is known quantity from measurement. The simulation results are compared with the analytical solution. It is found that the method can analyze the current distribution in the source conductors very accurately.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.110-112
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• 2003

Electric control of eddy coupling offers many new possibilities in process control and other industrial control applications. And a form of speed control for the load is affected for a system driven by costant frequency induction motor. This paper analysis speed-torque characteristic of the eddy-current coupling by using the 3-dimensional analytical method. Characteristic experiment is put into operation for the claw pole type eddy current coupling. Design procedure is presented based on the analysis.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1036-1038
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• 2003

Electric control of eddy coupling offers many new possibilities in process control and other industrial control applications. And a form of speed control for the load is affected for a system driven by costant frequency induction motor. This paper compare speed-torque characteristic of three types of eddy-current coupling by using the analytical method. And characteristic experiment of three types of eddy current coupling is put into operation. And then, this paper will discuss operational and magnetic field characteristic of three types model.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.115-118
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• 2020

As interest in the reduction of energy loss has increased in recent years, analysis of losses in power cables is becoming more important. The overall loss in the transmission system can be measured, but there are many difficulties in researching the loss in each internal structure. There are various factors in the type of loss, and the loss of external factors by previous research has been studied. However, there is little research on the cable internal loss. Since the metal sheath inside the cable is made of aluminum having a high conductivity, an eddy current is generated due to the current flowing in the conductor, thereby causing an eddy current loss inevitably. In this paper, the eddy current loss in metal sheath of 154 kV Cable was researched through FEM (Finite Element Method) electromagnetic analysis.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.748-750
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• 2001

This paper describes numerical analysis of eddy current testing for tube with axi-symmetric defect using boundary element method. In this ECT(Eddy Current Testing) numerical analysis. BEM and FEM are used to compare their characteristics and results of ECT, respectively BEM is easier than FEM to design geometrically complex domain because in case of BEM, domain is divided into segments or elements, but in case of FEM, domain is divided into small finite triangular or quadrilateral elements. For this reason asymmetry defect is used for this BE numerical analysis. As a result, the similar result can be obtained through both numerical analyses, and BEM can be applied to the numerical analysis of ECT.

• Progress in Superconductivity and Cryogenics
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• v.7 no.4
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• pp.32-36
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• 2005

The structure of a high-Tc superconducting power cable system is composed of these parts; (from the outer section) a liquid nitrogen cryostat, a vacuum cryostat, multi-layer high-Tc superconducting cable cores and a stabilizer and both cryostats during the stable operating period of the high-Tc superconducting power cable system are calculated by the numerical method. And the optimal conditions of the stabilizer and both cryostats, that minimize the eddy current losses, are derived from the analyzed results. The optimal results can be applied to the design and manufacture of the high-Tc superconducting power cable system.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.92-93
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• 1998

In this study, we have established the technique to estimate the gradient waveforms distorted by the eddy current in MRI. After obtaining the eddy current effect transfer function using the finite element method, we have used the transfer function to estimate the output gradient waveforms at any points inside the imaging region. We also present experimental results to be compared with estimated ones.