• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.3-5
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• 2003

This paper deals with the characteristics of a capacitor-run single-phase induction motor by changing of conductor bar numbers. The Finite Element Method (FEM) is used to analyze the starting characteristics according to the rotor initial starting point about conduction bar and the characteristic analysis at the rated condition is calculated by equivalent circuit based on symmetry coordinate theory Finally, the analysis results of the analysis models have different conductor bars in their rotor are compared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.829-830
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• 2006

The line-start permanent magnet synchronous motor has a high efficiency and an advantage in constant speed operation regardless of the effect of load variation. However it is difficult to predict the performance of characteristics accurately, because of the unbalanced starting torque with the initial starting position of the rotor and the generation of a break torque. In this paper the dynamic characteristics of the line-start permanent magnet synchronous motor are described and compared with those of the squirrel-cage induction motor through the simulation to find the characteristics of the permanent magnets and the rotor bars in the line-start permanent magnet synchronous motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.86-88
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• 2005

The line-start permanent magnet synchronous motor has a high efficiency and an advantage in constant speed operation regardless of the effect of load variation. However it is difficult to predict the performance of characteristics accurately, because of the unbalanced starting torque with the initial starting position of the rotor and the generation of a break torque. In this paper the dynamic characteristics of the line-start permanent magnet synchronous motor arc described and compared with those of the squirrel-cage induction motor through the simulation to find the characteristics of the permanent magnets and the rotor bars in the line-start permanent magnet synchronous motor.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.315-318
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• 2007

MATLAB/$SIMULINK^{TM}$ 환경 기반에서 일반적인 터보 축 엔진의 천이상태 및 시동 특성 해석을 위한 동적 시뮬레이션을 수행하였다. 터보축 엔진 구성품을 열역학 및 로터 동역학적인 관계식을 이용하여 모델을 구성하였다. 엔진 시동 특성은 보조동력장치에서 발생한 축력을 엔진 터빈에 전달시켜 엔진 각 구성품에서의 압력, 온도 및 축력의 변화 등에 대한 해석을 수행하였으며, 정상상태에서 작동 중인 모델엔진의 연료유량 변화에 대한 엔진 작동상황을 모사해 봄으로써 엔진 천이 특성에 대한 해석을 수행하였다. 향후, 엔진 제어기능을 기본 모델에 추가함으로써 보다 다양한 엔진 성능 시뮬레이션이 가능할 것으로 사료된다.

• 한국재료학회지
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• 제15권6호
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• pp.408-412
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• 2005

[ $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ ] phosphor particles with high photoluminescence intensity under long wavelength ultraviolet were prepared by spray pyrolysis. We investigated the effect of $NH_4F$ flux added into starting solution on the morphology and photoluminescence intensity of $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ phosphor prepared by spray pyrolysis. $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ phosphor particles prepared from starting solution containing $NH_4F$ flux had the maximum photoluminescence intensity at the post-treatment temperature of $1200^{\circ}C$ and the maximum photoluminescence intensity of $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ phosphor particles prepared from the starting solution containing $NH_4F$ flux was $137\%$ of that of the phosphor particles prepared from the starting solution without flux material. $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ phosphor particles prepared from starting solution containing $NH_4F$ flux had larger size and more aggregated morphology than those prepared from starting solution without flux material. The photoluminescence intensity of $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ phosphor particles prepared from starting solution containing $NH_4F$ flux above $3wt.\%$ had high photoluminescence intensities. The addition amount of $NH_4F$ flux showing the maximum photoluminescence intensity was $12wt.\%$. The optimum amount of $NH_4F$ flux was $5wt.\%$ when we considered the morphological and photoluminescence characteristics of $Ba_{1.5}Sr_{0.5}SiO_4:Eu$ ohosphor particles prepared by spray pyrolysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.807-808
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• 2006

This paper covers start-up characteristic of three phase induction motor. When three phase induction motor is started, the inrush current occurs. There are several ways of reducing starting current of a three phase motor. In this paper will explain and propose the types of part windings in order to reduce the starting current.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권2호
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• pp.257-268
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• 2014

In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR). First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D) turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

• 조명전기설비학회논문지
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• 제18권2호
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• pp.150-156
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• 2004

단상 전원에 의해 기동되는 영구자석형 단상 동기 전동기는 효율은 높지만, 회전 방향을 결정하기가 어렵다. 본 연구에서는 커패시터 운전 단상 동기 전동기의 기동 특성에 대하여 연구하였다. 고정자는 커패시터 운전 단상 유도기와 동일하지만, 회전자가 영구자석으로 구성된다. 이 경우는 회전자와 고정자 조건에 따라 기동 조건이 결정되고 모터의 회전 방향이 결정될 수 있다. 이 결과에서, 제안된 전동기는 낮은 기동토크를 요구하는 팬과 같은 부하에 적용될 수 있을 것으로 기대된다.

• 한국세라믹학회지
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• 제50권5호
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• pp.348-352
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• 2013

The evaluation of plasma resistance and the characteristics of yttria ceramics fabricated by calcination yttria as a starting material without dopants under an oxidation atmosphere was investigated. Regardless of the starting materials, as-received, and calcined yttria powder, XRD patterns showed that all samples have $Y_2O_3$ phase. The three cycling process inhibited a large grain, which occurs frequently during the yttria sintering, and a high density ceramic with a homogeneous grain size was obtained. The grain size of the sintered ceramic was affected by the starting powders. The smaller the grain size, the larger were the Young's modulus and KIC. Compared to $Al_2O_3$ and $ZrO_2$ ceramics, yttria ceramics showed a 3 times larger plasma resistance and a 1.4~2.2 times lower weight loss during the plasma etching test, respectively.

• 한국산업정보학회논문지
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• 제21권1호
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• pp.1-6
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• 2016

본 논문에서는 기생 트랜지스터를 억제하여 대기 전류를 낮춰 기동전류를 개선한 수직 PNP 트랜지스터의 특성을 소개한다. 기생 효과를 억제하기 위해, 회로 변경 없이 "DN+ 링크"를 사용하여 기생 PNP 트랜지스터를 억제 시킨 수직 PNP 트랜지스터를 설계하였으며, 표준 IC 프로세서를 이용한 LDO 레귤레이터를 제작했다. 제작된 기생 PNP 트랜지스터의 hFE 가 기존의 18에서 0.9로 감소하였다. 개선된 "DN+ 링크" 구조 수직 PNP 트랜지스터로 제작된 LDO 레귤레이터의 기동 전류는 기존의 기동 전류 90mA에서 32mA 로 감소되었다. 이로 인해 대기상태에서 저 소비전력을 구현한 LDO 레귤레이터를 개발하였다.