• Title/Summary/Keyword: winding methods

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A Study on the Western Shroud of Culture (서양 壽衣文化에 관한 考察)

  • 김경희;이순홍
    • The Research Journal of the Costume Culture
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    • v.9 no.3
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    • pp.398-411
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    • 2001
  • Funeral rites relate to the last ceremonies involving the process of human beings moving from this world to the other world, becoming part of a life which remarkably reflects the world after death. They can be said to be the best culture created by the conception of death. The ceremonies of mourning, or ubiquitius folk phenomena of all the ages from the ancient times to modern times, represent the mass belief of each nation in spiritual worlds as well as the feelings of individuals facing death. In so far as their methods are concerned, the ceremonies vary in accordance with ages, nations, regions and culture. The practices of today\`s funeral rites conducted in the West have been formed and changed throughout its long history. Now that the ceremonies are a combination of complicated cultures, they serve as an important tool for inquiring into the spiritual life of the people of an age in question and the pictures of the society concerned. Therefore this paper is designed to look into the culture of shrouds showing respect for the dead in the West. With the view of examining death, and grave clothes for them, but also with the spiritual culture of human beings in relation to death represented in their pictures. I resort to literature and materials related to the shrouds of the dead which appeared in a period from the Medieval Age to the 19th century.

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The Study on Technique and Design Appeared in Textile of Miaos in China (중국내 묘족의 직물에 나타난 기법과 문양 고찰)

  • 부애진;홍정민
    • Journal of the Korean Society of Costume
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    • v.37
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    • pp.149-162
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    • 1998
  • This study is thed Embroidery, Cross-stitchery, Weaving, Wax-Printing of technique and design appeared in textile of Miaos dwells in south-west among the minority people of china. The study is as follows. First, the technique of textile1) satin stitch, couching stitch, french-knot stitch, etc. using anther silk thread or cotton thread color 2) cross-stitchery 3) hand-weaving technique which is shaped other warp or weft using simple loom 4) the technique of dyeing of pattern using effect with wax. These methods are singly used mixing together, therefore doubled beauty. Second, these technuque of ornament have other independence, specially ornament apron, sling, sleeve borders, slack borderss, edge of upper garment, take off and put on easily, heighten effect of various ornament, can preserve many years. Third, Maker, female born in this country fashion by need of herself, used liberal method shown in unique creativity of life. This texture make standards capable female proud of intelligent and skill of herself. Fourth, Design appeared in textile like as pattern flying bird in the sky, strolling beast in the field, lion rolling gem, laughing dragon winding snake at gem, birks, flowers, fish, butterfly is used as the wish of long life, a lucky sign. They expressed creativity and unique conception using formation : the technique transform other shape using by omitting or adding or overestimating. Geometric pattern of tartan, revealing, Fifth, composition structure having balance and symmetry or contradiction towards center and circumstance of the center harmonized repeatedly method, expressed unique artful attraction by full composition.

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Development of Hybrid FRP-Concrete Composite Pile Connection (하이브리드 FRP-Concrete 복합말뚝의 연결부의 개발)

  • Lee, Hyoung-Kyu;Park, Joon-Seok
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.5 no.4
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    • pp.52-57
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    • 2014
  • Due to the advantageous mechanical properties of the fiber reinforced polymeric plastics(FRP), their application in the construction industries is ever increasing trend, as a substitute of structural steel which is highly vulnerable under hazardous environmental conditions (i.e., corrosion, humidity, etc.). In this study, hybrid FRP-concrete composite pile (HCFFT) connection is suggested. The HCFFT is consisted of pultruded FRP unit module, filament wound FRP which is in the outside of mandrel composed of circular shaped assembly of pultruded FRP unit modules, and concrete which is casted inside of the circular tube shaped hybrid FRP pile. Therefore, pultruded FRP can increase the flexural load carrying capacity, filament wound FRP and concrete filled inside can increase axial load carrying capacity. In the study, connection capacity of HCFFT(small and mid size) is investigated throughout experiments and finite element method. From the results of experiments, we suggested the connection methods about HCFFT pile connection.

Reference Frame Approach for Torque Ripple Minimization of BLDCM over Wide Speed Range Including Cogging Torque (코깅 토크를 포함한 광역 속도 영역상의 BLDCM의 토크 리플 최소화를 위한 기준 프레임 접근기법)

  • Park, Han-Woong;Cho, Sung-Bae;Won, Tae-Hyun;Kwon, Soon-Jae;Ham, Byung-Woon;Kim, Cheul-U
    • Proceedings of the KIEE Conference
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    • 2001.04a
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    • pp.33-36
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    • 2001
  • Torque ripple control of brush less DC motor has been the main issue of the servo drive systems in which the speed fluctuation, vibration and acoustic noise should be minimized. Most methods for suppressing the torque ripples require Fourier series analysis and either the iterative or least mean square minimization. In this paper, the novel approach to achieve the ripple-tree torque control with maximum efficiency based on the d-q-0 reference frame is presented. The proposed method optimize the reference phase current waveforms including even the case of 3 phase unbalanced condition, and the motor winding currents are controlled to follow up the optimized current waveforms by delta modulation technique. As a result, the proposed approach provides a simple and clear way to obtain the optimal motor excitation currents. The validity and practical applications of the proposed control scheme are verified through the simulations and experimental results.

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Initial Magnetic-Circuit Design of High Speed Permanent-Magnet Synchronous Machine (초고속 영구자석 동기기의 기초자기회로설계)

  • Joo, Daesuk;Hong, Do-Kwan;Woo, Byung-Chul;Woo, Kyung-Il;Park, Han-Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.1
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    • pp.7-13
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    • 2015
  • This paper presents mathematical models for high speed permanent-magnet synchronous machine. The mathematical method with two successive steps is used to estimate design parameter as well as the output power. At first, mathematical model for a linkage flux problem is employed to calculate the number of winding turns and stack length of armature core. The magnetic circuit model for an induced voltage and the electric circuit model for a current are modeled. The output powers of the electrical generator were evaluated by the mathematical techniques. The results of this mathematical methods predict the specifications of the machine and can be applied in the design stage of the electrical machine.

A Singular Value Decomposition based Space Vector Modulation to Reduce the Output Common-Mode Voltage of Direct Matrix Converters

  • Guan, Quanxue;Yang, Ping;Guan, Quansheng;Wang, Xiaohong;Wu, Qinghua
    • Journal of Power Electronics
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    • v.16 no.3
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    • pp.936-945
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    • 2016
  • Large magnitude common-mode voltage (CMV) and its variation dv/dt have an adverse effect on motor drives that leads to early winding failure and bearing deterioration. For matrix converters, the switch states that connect each output line to a different input phase result in the lowest CMV among all of the valid switch states. To reduce the output CMV for matrix converters, this paper presents a new space vector modulation (SVM) strategy by utilizing these switch states. By this mean, the peak value and the root mean square of the CMV are dramatically decreased. In comparison with the conventional SVM methods this strategy has a similar computation overhead. Experiment results are shown to validate the effectiveness of the proposed modulation method.

Study on the Transfer Functions for Detecting Windings Displacement of Power Transformers with Impulse Method

  • Shon, Chae-Hwa;Yi, Sang-Hwa;Lee, Heun-Jin;Kang, Dong-Sik
    • Journal of Electrical Engineering and Technology
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    • v.7 no.6
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    • pp.876-883
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    • 2012
  • The paper investigates three types of transfer function methods for detecting displacements of winding in a model transformer. To acquire these transfer functions, the measuring method of input voltage, current and its response is used in impulse method. The applied impulse voltages had three rising times, which were short rising time (less than 0.6 ${\mu}s$), medium rising time (about 0.8 ${\mu}s$) and long rising time (about 1 ${\mu}s$) in front waves. Every 10 measurements of voltage and current waves were averaged from 50 measurements of voltage and current waves. These transfer functions were tested in normal, 24mm elevated and 48mm elevated windings conditions and were analyzed with correlation coefficients and spectrum deviations. In the analysis, the results depend on the types of transfer functions and the rising times of input voltages.

Prediction of Iron Loss Resistance by Using HILS System (HILS 시스템을 통한 IPMSM의 철손저항 추정)

  • Jeong, Kiyun;Kang, Raecheong;Lee, Hyeongcheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.1
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    • pp.25-33
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    • 2015
  • This paper presents the d-q axis equivalent circuit model of an interior permanent magnet (IPM) which includes the iron loss resistance. The model is implemented to be able to run in real-time on the FPGA-based HIL simulator. Power electronic devices are removed from the motor control unit (MCU) and a separated controller is interfaced with the real-time simulated motor drive through a set of proper inputs and outputs. The inputs signals of the HIL simulation are the gate driver signals generated from the controller, and the outputs are the winding currents and resolver signals. This paper especially presents iron loss prediction which is introduced by means of comparing the torque calculated from d-q axis currents and the desired torque; and minimizing the torque difference. This prediction method has stable prediction algorithm to reduce torque difference at specific speed and load. Simulation results demonstrate the feasibility and effectiveness of the proposed methods.

Brushless DC Motor Electromagnetic Torque Estimation with Single-Phase Current Sensing

  • Cham, Chin-Long;Samad, Zahurin Bin
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.866-872
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    • 2014
  • The purpose of this paper was to find an effective method for measuring electromagnetic torque produced by a brushless DC motor with single-phase current sensing in real-time. A torque equation is derived from the theory of brushless DC motor. This equation is then validated experimentally with a motor dynamometer. A computer algorithm is also proposed to implement the electromagnetic torque estimation equation in real-time. Electromagnetic torque is a linear function of phase current. Estimating the electromagnetic torque in real-time using single-phase current is not appropriate with existing equations, however, because of the rectangular alternating-pulse nature of the excitation current. With some mathematical manipulation to the existing equations, the equation derived in this paper overcame this limitation. The equation developed is simple and so it is computationally efficient, and it takes only motor torque constant and single-phase current to evaluate the electromagnetic torque; no other parameters such as winding resistances, inductances are needed. The equation derived is limited to the three-phase brushless DC motor. It can, however, easily be extended to the multiphase brushless DC motor with the technique described in this paper.

Efficiency Optimization with a Novel Magnetic-Circuit Model for Inductive Power Transfer in EVs

  • Tang, Yunyu;Zhu, Fan;Ma, Hao
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.309-322
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    • 2018
  • The technology of inductive power transfer has been proved to be a promising solution in many applications especially in electric vehicle (EV) charging systems, due to its features of safety and convenience. However, loosely coupled transformers lead to the system efficiency not coming up to the expectation at the present time. Therefore, at first, the magnetic core losses are calculated with a novel magnetic-circuit model instead of the commonly used finite-element-method (FEM) simulations. The parameters in the model can be obtained with a one-time FEM simulation, which makes the calculation process expeditious. When compared with traditional methods, the model proposed in the paper is much less time-consuming and relatively accurate. These merits have been verified by experimental results. Furthermore, with the proposed loss calculation model, the system is optimized by parameter sweeping, such as the operating frequency and winding turns. Specifically, rather than a predesigned switching frequency, a more efficiency-optimized frequency for the series-parallel (SP) compensation topology is detected and a detailed investigation has been presented accordingly. The optimized system is capable of an efficiency that is greater than 93% at a coil separation distance of 200mm and coil dimensions of $600mm{\times}400mm$.