• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.741-743
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• 2002

Some different types of joining between two parallel high Tc superconducting tapes were prepared and I-V characteristic curves were obtained at the atmosphere of liquid nitrogen. Resistances in joint parts were estimated from I-V curves. We selected the best jointing method among these methods and its resistance were obtained at 28K. The availability of this joint method for fabricating HTS field coils is discussed.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.4
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• pp.394-398
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• 2013

This paper presents output characteristics of a linear switched reluctance motor (LSRM) with excitation windings wound by using high-temperature superconducting (HTS) tapes. In a double-sided LSRM, Bi-2223 or YBCO tape conductors are used for the excitation windings. The characteristics of the LSRM are obtained by a finite element method analysis. We can obtain large thrust compared with a conventional LSRM by using YBCO tape conductors. Also, the effect of a configuration of the YBCO coil on the thrust is calculated. We discuss a suitable coil configuration for the average thrust upgrading.

• Progress in Superconductivity and Cryogenics
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• v.6 no.1
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• pp.1-5
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• 2004

Long length of Bi-2223/Ag superconducting wives were fabricated by stacking and drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to predict the sausaging and stress limit. Rolling Parameters such as thickness. width and winding tension were investigated to roll the tape with uniformity. 1 km length of Bi-2223/Ag superconducting wires were fabricated without any breakage. Critical current (Je) of 270 m length of superconducting tapes was measured over than $70 A/cm^2$ continuously after final sintering.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.599-600
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• 2006

Multi-slacked HTS tapes are needed to conduct large current in the power application of superconducting machine. This paper deals with the transport current loss of multi-stacked YBCO coated conductor. YBCO coated conductor that was used in this experiment has two Cu layers above and below of YBCO layer for stabilization. Transport losses of four different stacks, single, 2 stack, 3 stack and 4 stack, were measured. Measured results were compared analytic equation suggested by Norris.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2231-2232
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• 2006

Multi-stacked HTS tapes are needed to conduct large current in the power application of superconducting machine. This paper deals with the transport current loss of multi-stacked YBCO coated conductor. YBCO coated conductor that was used in this experiment has two Cu layers above and below of YBCO layer for stabilization. Transport losses of four different stacks, single, 2 stack, 3 stack and 4 stack, were measured. Measured results were compared analytic equation suggested by Norris.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.9
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• pp.572-577
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• 2000

This paper describes the test results of a single phase 3kVA high temperature superconducting power transformer. The tapes are made with Bi-2223 and have silver alloy as the matrix. Four double pancake windings are used. Among them two double pancake windings are connected in series for high voltage winding and the others are connected in parallel for low voltage winding. The rated voltage and current of primary winding and secondary winding are 220/110V. 13.7/27.3A. Fundamental characteristics are obtained through short circuit and no load test. The over load capability and characteristics are investigated.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.170-172
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• 2000

This paper deals with the characteristic analysis of the flux damper with respect to the load, and the stability of Ag/Bi-2223 tapes in a high-Tc superconducting (HTS) synchronous motor. To find out the magnetic field distribution in a detailed model of the actual motor, the experimentally measured currents of the armature and the field windings are used as input parameters. The simulation results show that the flux damper shields the time varying field up to 10%, reduces armature reactance during the motor operation and during load changes, improving the stable motor operation. And it was observed that the flux damper generates loss by means of leakage flux, but this is not significant and it doesn't degrade the performance of the TS synchronous motor.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.688-691
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• 1997

Good quality superconducting $YBa_2Cu_30_{7-{\delta}}$(YBCO) thin films were grown on Hastelloy (Ni-Cr-Mo alloys) with yttria-stabilized zirconia(YSZ) buffer layers by in situ pulsed laser deposition in a multi-target processing chamber. Generally, Hastelloy exhibits excellent resistance to corrosion, fatigue, thermal shock, impact, and erosion. However, it is difficult to make films on flexible metallic substrates due to interdiffusion problems between metallic substrates and superconducting overlayers. To overcome this difficulty, it is necessary to use YSZ buffer layer since it will not only limit the interdiffusion process but also minimize the surface microcrack formation due to smaller mismatch between the film and the substrate. In order to enhance the crystallinity of YBCO films on metallic substrates, YSZ buffer layers were grown at various temperatures different from the deposition temperature of YBCO films. On YSZ buffer layer grown at higher temperature than that for depositing YBCO film, the YBCO thin film was found to be textured with c-axis orientation by x-ray diffraction and had a zero-resistance critical temperature of about 85K.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.257-260
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• 2003

Bi-2223 tape is one of the most widely used HTS tapes for power application. This paper presents the basic properties such as temperature and resistivity rise of the Bi-2223 tape which is exposed to the over current. Temperature and resistivity were measured by E-type thermocouple and voltage taps. Results of the measurement showed that rise of voltage depended on the magnitude of the over current until several times of the rated current. When the current largely exceeded the rated current, rise of voltage depended on the magnitude of the resistivity of the Ag matrix because temperature of the matrix increased to a great extend.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1265-1266
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• 2006

Multi-stacked HTS tapes are needed to conduct large current in the power application of superconducting machine. This paper deals with the transport current loss of multi-stacked YBCO coated conductor. YBCO coated conductor that was used in this experiment has two Cu layers above and below of YBCO layer for stabilization. Transport losses of four different stacks, single, 2 stack, 3 stack and 4 stack, were measured. Measured results were compared analytic equation suggested by Norris.