• Journal of the Korean Society for Precision Engineering
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• v.33 no.2
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• pp.115-119
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• 2016

Winding is one of the major processes in roll-to-roll systems. Taper tension profile in a winding determines the distribution of stress in the radial direction, i.e., the radial stress in the wound rolls. Maximum radial stress is major cause of material defect, and this study has been actively proceeded. Traditional models of radial stress model were focused on flexible and light substrate. In this study, we developed an advanced radial stress model including effects of both these parameters(weight and stiffness) on the radial stress. The accuracy of the developed model was verified through FEM(Finite Element Method) analysis. FEM result of maximum radial stress value corresponds to 99 % in comparison to result with the model. From this study, the material defects does not occur when the steel winding. And steel industry can be applied to improve the winding process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.1
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• pp.68-72
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• 2013

The series connection-type superconducting fault current limiter (SFCL) with two magnetically coupled circuits was suggested and its effectiveness through the analysis on the current limiting and recovery characteristics was described. The fault current limiting characteristics of the proposed SFCL as well as the load voltage sag compensating characteristics according to the winding direction were investigated. To confirm the fault current limiting and the voltage sag suppressing characteristics of the this SFCL, the short-circuit tests for the simulated power system with the series connection-type SFCL were carried out. The series connection-type SFCL designed with the additive polarity winding was shown to perform more effective fault current limiting and load voltage sag compensating operations through the fast quench occurrence right after the fault appears and the fast recovery operation after the fault removes than that with the subtractive polarity winding.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.835-840
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• 2023

Compared to 3D FEM, 2D FEM can be analyzed by simplifying the model and conditions. However, with respect to coil conditions, in many cases, direction of coils(upward, downward, entrance, exit, etc.) are sequentially configured and set up the FEM analysis conditions. This paper shows simplification of coil conditions and reduction of analysis time by applying the equivalent winding method composed of one FEM coil even if it has multiple slots, and shows consistency of results by applying it to a winding type magnetic gear.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.70-77
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• 2006

We have fabricated an integrated three-phase flux-lock type SFCL, which consists of an YBCO($YB_a2Cu_3O_7$) thin film and a flux-lock reactor wound around an iron core of each phase. In order to apply the SFCL in a real power system, fault analyses for the three-phase system are essential. The short-circuit currents were effectively limited by adjusting the numbers of winding of each secondary coil and their winding directions. The flux flow generated in the iron core cancelled out under the normal operation due to the parallel connection between primary and secondary windings. However, the flux-lock type SFCL with same iron core was operated just after the fault due to the flux generating in the iron core. To analyze the current limiting characteristics, the additive polarity winding was compared with the subtractive one in the flux lock reactor. Whenever a single line-to-ground fault occurred in any phase, the peak value of the line current of the fault phase in the additive polarity winding increased up to about 12.87 times during the first-half cycle. On the other hand, the peak value in the subtractive polarity winding increased up to about 34.07 times under the same conditions. This is because the current flow between the primary and the secondary windings changed to additive or subtractive status according to the winding direction. We confirmed that the current limiting behavior in the additive polarity winding was more effective for a single-line-to-ground fault

• Proceedings of the KIEE Conference
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• summer
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• pp.1133-1135
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• 2004

Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconducting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and ac loss. In this paper, the transport current and magnetic field distributions at conducting layers were investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer. The transport current distribution due to the pitch length and winding direction was improved in case of HTSC power cable with shield layer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.52-56
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• 2011

The ongoing Superconducting Fault Current Limiter(SFCL) development mainly has focused on the application of commercializaton and power system through combining with normal-conducting device, moving away from current-limiting method, which is solely dependant on the existing superconductor. Compared to the structural development above, on the other hand, the research on applying superconducting current-limiting element to SFCL, the heart of SFCL, still has a lot left to do, apart form traditional resistive type SFCL. In this study, we looked into the current limiting characteristic of SFCL using core and coil. YBCO coated conductor with stainless steel stabilizer layer was verified by the excellent of current-limiting element of the resistive type SFCL that has a high Jc and index as well as being superior in mechanical property. Also, we study temperature characteristics and resistance characteristics, max voltage, response time and current-limiting ability that can be an indicator as current-limiting element while applying to superconducting current-limiting element caused by variation of winding direction, winding ratio of SFCL using core and coil.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.43-45
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• 2008

In this paper, the operational characteristics of SFCL with magnetically coupled two coils were modeled and simulated by PSCAD/EMTDC. The dependence of the line voltage sag on the resistance of superconducting element during the fault period was analyzed. Through the analysis for the winding direction of two coils, the line voltage sag in case of the additive polarity winding was observed to be more improved compared to the case of the subtractive polarity winding.

• Korean Journal of Computational Design and Engineering
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• v.3 no.1
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• pp.22-30
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• 1998

The deflection yoke (DY) controls the direction of the electron beam that falls on the screen of the television monitor. Its quality depends on the shape and density of coils wound around the DY coil separator. Winding frames are used to make these coils, and therefore, their shapes are essential in making quality coils. A reverse engineering(RE) is applied to create the 3D model of the winding frame. It considerably shortens the design verification time and shows the level of accuracy that is feasible in the production mode. The paper explains each step of the reverse engineering process in detail.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.666-670
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• 2011

In this paper, a method for detecting broken rotor bar and stator winding fault in a low voltage squirrel-case induction motor using an air-gap flux variation analysis is proposed to develop a simple and low cost diagnosis technique. To measure the leakage flux in radial direction, a radial flux sensor is designed as a search coil and installed between stator slots. The proposed method is able to identify two kinds of motor faults by calculating load condition of motors and monitoring abnormal signals those are related with motor faults. Experimental results obtained on 7.5kW three-phase squirrel-cage induction motors are discussed to verify the performance of the proposed method.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.23-25
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• 2005

This paper describes analysis of transformer sheet winding losses and temperature rise. Sheet windings are used if transformer rating currents are so high that one meets current density limit on windings. Unlike stranded windings, sheet windings may be locally healed due to R direction flux. Winding losses with eddy current effect are calculated by finite element electromagnetic analysis and temperature rise is also calculated by Computational Fluid Dynamics (CFD) with loss result.