• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.954-955
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• 2008

In this paper, the voltage harmonics are investigated in terms of the voltage sag versus the time constants of electric machinery under the source voltage variation condition. The electric machinery and compensation equipment are established on the proposed design scheme based on voltage quality effect assessment technology. It have been analyzed how the variation of harmonic order, the output current, the DC-Link voltage and the induction motor speed is carried out under the voltage sag and switching frequency variation.

• 한국유체기계학회 논문집
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• 제15권1호
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• pp.27-35
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• 2012

A numerical simulation for particle collection efficiency in a wire-plate electrostatic precipitator (ESP) has been performed. Method of characteristics and finite differencing method (MOC-FDM) were employed to obtain electric field and space charge density, and lattice boltzmann method (LBM) was used to predict the Electrohydrodynamic (EHD) flow according to the ion convection. Large eddy simulation (LES) was considered for turbulent flow and particle simulation was performed by discrete element method (DEM) which considered field charging, electric force, drag force and wall-collision. One way coupling from FDM to LBM was used with small and low density particle assumption. When the charged particle collided with the collecting plate, particle-wall collision was calculated for re-entertainment effect and the effect of gravity force was considered.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.231-235
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• 1990

Soft magnetic silicon steels containing up to 6.5wt% of silicon were prepared by powder metallurgical processing and their magnetic properties were evaluated. The magnetic properties of P/M silicon steels are similarly affected by the silicon addition as those of conventional ingot processed ones but are also significantly affected by density and interstitial impurities particularly oxygen content. Magnetic flux density, $B_{10}$ and coercivity, Hc, tends to decrease with silicon content whereas maximum permeability, ${\mu}m$, decreases first and then increases rapidly above 5 wt% silicon. Increasing density also increases magnetic flux density and maximum permeability but reduces coereivity. The latter two properties are, however, affected more strongly with oxygen content.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.247-249
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• 1998

This paper has proposed an optimized universal motor for improving its performance and cost using FEM program. To do this, various design parameters are set such as air gap length, shape of stator and pole shoe, rotor slot, rotor shaft diameter, etc. As results, the optimized model has made good improvement compared with those of the initial.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.979-980
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• 2007

This paper deals with the analysis error in the time step FEM which is applied to analyze the electric machinery. In order to calculate the error accurately, a simple inductor structure which has analytical solution is designed, and then the time step analysis for the equivalent circuit and time step FEM is performed respectively. Finally, according to the analysis methods. the results are compared and discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1155-1156
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• 2007

This paper deals with dynamic simulation and design characteristic of Linear Switched Reluctance Motor (LSRM). First, we derived design factor from pole arc ratio of stator and mover. Second, we decided design parameter from design factor using time constant. Finally, analyze dynamic characteristics for LSRM using simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.181-182
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• 2007

This paper presents the system design of high speed linear synchronous machine in the required speed and thrust considering power of inverter. in this paper, the design of manufacturing motor is optimized by characteristics of motor parameters with the variation of coil turns of rotor and stator. And, the dynamic simulation are performed from the (d-q) transformation of the current and voltage and the mechanical dynamic equation composed of the mover mass and damping ratio. Finally, the results of design and analysis are verificated by finite element analysis.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.70-70
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• 2017

국내에서 사용되는 밭농업용 전동차는 산업용 DC MOTOR를 사용하고 있는 실정이다 왜냐하면 농업용 DC MOTOR는 그 수요가 미미해서 개발상품이 거의 없는 실정이다. 산업용DC MOTOR는 고정된 장치에 부착이 되어 있어 사용상에 별 문제가 없지만 밭농업용 전동차는 비포장 도로에 사용되고 있어 충격이나 과부하에 견디지 못하여 운행도중 심한충격이나 하중 또는 진동에 반복하중에 견디지 못하여 파괴되거나 소음등이 많이 나는경우가 많다. 따라서 본 연구에서는 이를 개선하기 위해 감속기의 재질을 분석하고 마찰 마멸이 일어나는 부분의 재질변경과 표면열처리 등을 통하여 내구성을 증대에 대한연구를 실행 하였다.

• KSTLE International Journal
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• 제4권2호
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• pp.37-42
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• 2003

One of the obstacles for a magnetic bearing to be used in the wide range of industrial applications is the failure modes associated with magnetic bearings, which we don't expect for conventional passive bearings. These failure modes include electric power outage, power amplifier faults, position sensor faults, and the malfunction of controllers. Fault-tolerant magnetic bearing systems have been proposed so that the system can operate in spite of some faults in the system. In this paper, we designed a fault-tolerant magnetic bearing system for a turbo-molecular vacuum pump. The system can cope with the actuator/amplifier faults which are the most common faults in a magnetic bearing system. We implemented the existing fault-tolerant algorithms to experimentally prove the adequacy of the algorithms for industrial applications. As it turns out, the system can operate even with three simultaneously failing poles out of eight actuator poles.

• 한국입자에어로졸학회지
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• 제4권2호
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• pp.37-50
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• 2008

Concerns on centrifugal classifiers, of which have cut sizes are below few micrometers, have been increased and it is prospected to be used in extensive industries, such as manufacturing the fine minerals, cosmetics, advanced electric materials, and life science. This paper reviews the recent progress of research and development on the centrifugal classifiers. General categorization of classifiers for feeds was assessed and separation mechanism of the classifiers was followed. History of centrifugal classifiers was explored and some points to be improved were briefly indicated. Fundamental theory of the classification by centrifugal classifiers was pearly studied, and advanced and further understandings on factors affecting the separation or grading efficiency are described. Factors determining the classification precision and efficiency of centrifugal classifiers, such as geometry, rotational speed and inclined angle of rotating vanes, feed and air flow rates, and rotor dimensions are reviewed.