• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2181-2186
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• 2014

Generally, the motor inside vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping for very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering the starting current of the Brushless DC (BLDC) Motor through the Finite Element Method(FEM). As a result, the partial irreversible demagnetization was occurred by starting current at the end of Permanent Magnets of the basic model. To solve this problem, the flux barrier design was performed and the flux on the rotor core was limited. Accordingly, demagnetization endurance and operating characteristics were improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.232-234
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• 1994

In this paper. to estimate starting torque of synchronous motor by simple test, we propose a new method which is the combination of commercial tests and single phase AC applied test of synchronous motor. A driving characteristic was examined when field winding is supplied a de and chopper current. The starting characteristics are assumed and agreed with actual data.

• 전기학회논문지
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• 제63권1호
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• pp.48-53
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• 2014

Generally, the usage motor in the vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping during very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering starting current of Brushless DC Motor (BLDCM) through Finite Element Method(FEM). As a result, the end of Permanent Magnet (PM) in the basic model was occurring a partial irreversible demagnetization by starting current. To solve this problem, the installing flux barrier was limited to flux line on the core. Accordingly, demagnetization endurance and operating characteristics were improved.

• 전기의세계
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• 제13권4호
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• pp.10-15
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• 1964

It is well known that the starting characteristics of the cold cathode type discharge tube have photoelectric effects by the incident light from outside. After making the cold cathode type discharge tubes to be avaiable for popularizing, the present paper was devoted primaliry to a study of relations between the starting characterstics and photoelectric effects of discharge tube under the oight circumstances of day light, incandescent lamp, flouresent lamp, and mercury lamp we used frequently. The result of this investigation show that the photoelectric effects by flourescent lamp emitting short wave length having close ralation to the photoelectric effects is greater than incandescent lamp or day light, and also mercury lamp emitting shorter wave length than flourescent lamp indicates the greatest photoelectric effects.

• 대한기계학회논문집B
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• 제25권11호
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• pp.1543-1551
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• 2001

The characteristics of starting flow of a six-blade Rushton turbine mixer were investigated by using a cinematic Particle Image Velocimetry technique. The flows were quantified by measurements of velocity fields with a 4 ms time interval for a blade rotational speed of 100 r.p.m, so that the turbine Reynolds number(ND$^2$/ ν) was fixed to 6,960. The radial shedding of the trailing vortices starts from passing four blades after the beginning of rotation. It clearly shows that the vortex pairing phenomena caused by the interactions between trailing cortices firm consequtive blades. The average convection velocity of the radial flow is found to be 28 % of the tip velocity. The starting flow seems to arrive at a steady state after 8 revolutions in this study, which corresponds nearly one circulation through the bulk flow trajectory with the average radial convection velocity.

• 한국추진공학회지
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• 제23권5호
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• pp.10-18
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• 2019

Center Body Diffuser (CBD)의 Center Body (CB) 형상에 의한 유동 특성 및 시동압력을 해석하였다. CB 위치와 Cone 각도의 변경을 통해 초음속 유동 특성 및 시동압력을 비교하였다. CB 위치를 변수로 하여 Diffuser 해석한 결과, 유동의 모멘텀의 형성에 따라 강한 경사충격파의 발생위치가 달라지는 것을 확인하였다. 또한 경사충격파가 발생할 경우, 초음속 유동의 방향이 디퓨저 벽면으로 유도되는 것을 확인하였다. Cone 각도 변화에 따른 경사충격파의 각도 차이로 인하여, CBD의 시동압력이 영향을 받는 것을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.829-832
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• 2010

가스터빈엔진의 시동을 위해서는 점화가 가능한 공기 및 연료 조건이 되도록 외부 동력으로 엔진을 가속시켜 주어야 한다. 항공기용 소형 가스터빈엔진의 전기식 시동시스템은 구조가 간단하고 중량이 작아 소형 항공기에 주로 사용된다. 가스터빈 엔진의 전기 시동시스템 해석을 위해서는 배터리, 시동 모터 특성 및 엔진 drag 토크의 분석이 필요하며, 엔진의 사용 온도에 따라 각각의 특성을 반영하여 시동 시스템을 분석하여야 한다. 본 논문에서는 소형 가스터빈엔진의 전기시동 시스템 기본설계 과정 및 주요한 설계 파라메터에 대하여 기술하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.985-987
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• 2011

본 논문은 파생형엔진의 설계를 위해 시동시간 예측모델을 개발하는 경우를 다루었다. 파생형엔진 설계를 위해 압축기/터빈의 특성맵을 새로 제안한 Modified Pump Scaling Law(MPS)방법을 사용하여 시동모델링에 필요한 아이들 이하 회전수(sub idle rpm) 영역으로 확장시켰고, 기준엔진의 손실특성에서 압력/온도와 엔진별 특성차이를 고려한 파생형엔진의 손실모델을 도출하였다. 이러한 특성을 반영한 파생형엔진의 시동시간 예측모델은 시험결과와 비교하여 비교적 양호한 결과를 나타내었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.321-324
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• 1998

A single phase induction motor (SPIM) rated in fractional horsepower is widely used in home and industrial equipment: washing machines, fans, refrigerators, etc. In this paper, authors present the experimental results of the SPIM under controlling of currents of main and auxiliary windings by using a one-chip micro stator(OMS). This new starting method is developed to replace the conventional starting device consisted with a mechanical switch and a capacitor. In mentioned method, the soft-starting of SPIM is simply implemented and higher efficiency is obtained in comparison with conventional condenser type SPIM.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권1호
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• pp.70-76
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• 2000

This paper describes a one-chip micom controller and phase angle control method for self-starting and energy saving of single-phase induction motor. The proposed method is based on the optimal efficiency control which is running by variable phase angle of main winding current such as to maintain the maximum efficiency characteristics of the motor, in voltage control with TRIAC. Experiments are focused on a capacitor starting single-phase induction motor. The optimal energy saving by variable phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.