• Transactions on Electrical and Electronic Materials
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• v.7 no.2
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• pp.87-89
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• 2006

We investigated the current limiting characteristics of flux-lock type superconducting fault current limiter(SFCL) according to inductance variation of coil 2. The flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil through an iron core, and the secondary coil is connected to the superconducting element in series. The operation of the flux-lock type SFCL can be divided into the subtractive and the additive polarity winding operations according to the winding directions between the coil 1 and coil 2. The current limiting characteristics in two winding directions were dependent of on the ratio of the number of turns of coil I and coil 2. The fault current increased when the number of turns of coil 2 increased in the subtractive polarity winding. On the contrary, the fault current decreased under the same conditions in case of the additive polarity winding.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.269-275
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• 2005

A flux lock-type SFCL consists of two coils which are wound in parallel each other through an iron core, and a HTSC thin film connects in series with coil 2. The operation of the flux-lock type SFCL can be divided into the subtractive polarity winding and the additive polarity winding operations according to the winding directions between coil 1, coil 2. When a fault occurs, the fault current in the HTS thin film exceeds the critical current so that resistance is generated in the HTS film, and thereby the fault current is limited by an instant rise in the impedance of the flux-lock type SFCL. We investigated he variances of initial fault current limiting instant according to the ratio of inductance of coil 1 and coil 2 in the flux-lock type SFCL. It was confirmed from experiments that the initial fault current limiting instant in the subtractive polarity and additive polarity windings were faster as the ratio of coil 2' inductance for coil 1's inductance increased. The 1st peak of fault current in case of the subtractive polarity winding was higher as the ratio of coil 2's inductance for coil 1's inductance increased. On the other hand, in case of the additive polarity winding, the 1st peak of fault current was lower.

• Transactions on Electrical and Electronic Materials
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• v.17 no.4
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• pp.231-234
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• 2016

The AC insulation breakdown voltage was investigated for seven types of winding coils made of polyamideimide (PAI), flexural PAI (nanosilica 5 wt%) and anti-corona PAI (nanosilica 15 wt%) wires with various winding coil diameters of φ5, φ15 and φ25 mm. The winding coil was made of enameled wire with an enamel thickness of 30~50 μm, and the rectangular copper wire had a thickness of 0.77~ to 0.83 mm and width of 1.17~ to 1.23 mm, respectively. The insulation breakdown voltages of the original PAI coils with diameters of φ5, φ15 and φ25 mm were 7.30, 6.58, and 5.95 kV, respectively, and those values decreased as the winding coil diameter increased, regardless of the wire types.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.714-717
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• 2010

The improved flux-lock type superconducting fault current limiter (SFCL) is composed of a series transformer and superconducting unit of the yttrium-barium-copper-oxide (YBCO) coated conductor. In this paper, we investigated current limiting characteristics through winding direction of coil 2 and variable number of coil 1 and coil 2 in improved flux-lock type SFCL. The better fault current characteristics and the burden of YBCO coated conductor can be confirmed from the experimental result in the higher turn ratio of coil 1 and coil 2 in the additive conditions. In case of subtractive condition, we can confirm a similar result in the same case of experimental conditions. but the burden of YBCO coated conductor has been increased from an increase in winding numbers of coil 2.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.61-64
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• 2004

In this paper, we investigated the variations of initial fault current limiting instant according to fault angles in the flux-lock type SFCL. The flux-lock type SFCL consists of the coil 1 and the coil 2 that are wound in parallel each other through an iron core. The operation of the flux-lock type SFCL can be divided into the subtractive polarity winding and the additive polarity winding operations according to the winding directions between the coil 1 and coil 2. The subtractive polarity winding operation could be analyzed with three modes. On the other hand, the additive polarity winding operation could be analyzed with five modes. The variations of initial fault current limiting instant in two winding directions were dependent on the fault angles. It was confirmed from experiment that the fault current limiting instant was getting faster and the magnitude of fault current at the initial fault time was getting higher for higher fault angle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.9
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• pp.1589-1596
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• 2003

In this paper, we performed the improvement study for the dynamic characteristics enhancement of the motor stator coil vertical winding machine. The dynamic characteristics improvement was done by means of the optimized design and the weight reduction of the flyer configuration, modified design of the servo control system for the flyer and the former actuation, and the development of jump timing digital circuit for the reduction of former jumping error. As the results, the maximum winding speed pattern of the developed machine was attained up to 3000rpm and also reduced the jumping error. In conclusion, domestic design technology for manufacturing the motor coil vertical winding machine was established through this study.

• Fire Science and Engineering
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• v.21 no.4
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• pp.59-64
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• 2007

We studied on the fires about the electrical motors in this paper. We compared and analyzed about the transformation and damage state of single-phase induction motors used in the home appliances when we applied electrical overload and exterior flame. This experiment was progressed by the electrical overload application test and the exterior flame application test through the locked rotor of motor. In case of the exterior flame application test, it is divided into the apply voltage case and not apply voltage case. The result of an experiment through the locked rotor of motor, it was able to observe the short-circuit marks between layers at the winding coil parts, and it was appeared a transformed dendritic tissue structure of winding coil by the electrical overload test. The application voltage and the application exterior flame, it was confirmed that the stator winding coil parts were remain original shapes and observed that the color of the winding coil's circumference was changed to red. The non-application voltage and the application exterior flame, it was observed that the stator winding coil parts were transformed quite from original shapes. It was observed that the color of the winding coil and circumference parts was changed to red at the same case of non-application voltage.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.1
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• pp.13-18
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• 1999

To fabricate a 0.7 FJ, 100 kVA $\mu$SMES device for improving power quality in sensitive electric loads, we developed a design code for a $\mu$SMES device and designed the 0.7 MJ $\mu$SMES device by using it. In this study special emphasis was placed in influence of winding tensions on quench currents of superconducting coils because dry superconducting coils are usually quenched by local disturbances due to strand motions. We first investigated the quench currents of a few kA class superconducting cables for various winding tensions experimentally. To prove the validity of the code and develop all techniques related to fabrication and test of the 0.7 MJ $\mu$SMES device, a smaller size superconducting coil was wound with high winding tension of about 15 kgf/$mm^2$ based on the test results of superconducting cables and tested. It isshown form the test results that designed parameters for the smaller size superconducting coil are in good agreements with measured ones and the quench current of the coil with high winding tension reaches nearly to the critical current of the superconducting cable without any training effects.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.975-980
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• 2001

Like composite material. the coil winding pack of the KSTAR (Korea Superconducting Tokamak Advanced Research) consist of multiphase element such as metallic jacket material for protecting superconducting cable, vacuum pressurized imprepregnated (VPI) insulation, and corner roving filler. For jacket material, four CS (Central Solenoid) Coils, $5^{th}$ PF (Poloidal Field) Coil, and TF (Toroidal Field Coil) use Incoloy 908 and $6-7^{th}$ PF coil, Cold worked 316LN. In order to analyze the global behavior of large coil support structure with coil winding pack, it is required to replace the winding pack to monolithic matter with the equivalent mechanical properties, i.e. Young's moduli, shear moduli due to constraint of total nodes number and element numbers. In this study, Equivalent Young's moduli, shear moduli, Poisson's ratio, and thermal expansion coefficient were calculated for all coil winding pack using Finite Element Method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.694-697
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• 2009

The separated three-phase flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO coated conductor. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO coated conductor was connected with secondary coil in parallel. In this paper, we investigated the current limiting characteristics through winding number of coil 2 and winding direction in the flux-coupling type SFCL. Through the analysis, it was shown that additive polarity condition and lower winding number of coil 2 have advantaged from the point of view of fault current limiting and burned of YBCO coated conductor.