• 대한기계학회논문집B
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• 제23권1호
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• pp.114-122
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• 1999

Reignition as special cases of acoustic pressure responses of flame are numerically studied by employing methanol droplet flame as a laminar flamelet. Quasi-steady flame responses occur in the range of small amplitude, low frequency oscillation. Reignition phenomena can occur when, by increasing the frequency of large amplitude acoustic pressure, the magnitude of characteristic acoustic time is the same order of that of characteristic reaction time of flames. And more increasing of amplitude of acoustic pressure induces the direct extinction of flame. Flame can sustain its own intensity even under the steady extinction temperature in case of high frequency acoustic oscillation, and this tendency is remarkable with increasing frequency. Reignition regime with respect to amplitude and frequency of acoustic pressure doesn't exist in low frequency($10^2$ Hz, in this study), but broadens with frequency of acoustic pressure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.15-17
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• 1994

As VCB has many advantages which is an excellent interruption capability, compact structure, easy maintenance and light weight, it has been widely used as a load breaker. But steep-fronted surge voltage due to high frequency extinguishing capability in switching has been occurred. If it impinges into induction motor, it acts on the electrical stress, and causes to deteriorate winding insulation. In this research, in order to protect motor insulation from the steep-fronted reignition surge, the occurring condition, the cause of the reignition surge and the influence of circuit parameters which have been an effect on the occurrence of reignition and multiple reignition surge has been also analyzed.

• 전기학회논문지
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• 제62권2호
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• pp.190-195
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• 2013

Vacuum circuit breaker(VCB) has been widely used for interruption of load current and fault current for high voltage motor in the industrial field. Its arc extinguishing capability is excellent compared to other breakers. But it has the potential to cause multi reignition surge by high extinguishing capability. Surge voltage is generated by the opening and closing of VCB. Multi reignition surge of VCB is steep-fronted waveform. It may have a detrimental effect on the motor winding insulation. So, most of users install a protection device to limit steep-front waveform at the motor terminal or breaker side. So, most of users install a protection device at the motor terminal or breaker side. This protective device is surge absorber(SA) such as ZnO and RC type. In this study, we analyzed whether there is any effect when two type SA is applied to the VCB multi reignition surge. We confirmed that ZnO SA is slightly more effective than RC SA for reduction of multi reignition surge.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.581-586
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• 2000

Gas metal arc welding(GMAW) uses a continuously fed electrode as a filler metal. The arc is shielded from atmospheric contamination by an inert gas active or inert/active gas mixture delivered through the welding gun and cable assembly. The recent research topics on $CO_2$ are welding machines are focused mainly on the reduction method of generated spatter by using new type consumable electrode metal or inverter control method. The various current waveform control methods have been researched for welding performance improvement. Until now current waveform control methods reduce to spatter occurred by instantaneous short circuiting,. but these methods is drawback that no reduce spatter occurred by arc reignition. In this paper the previous arc reignition current control method for welding performance improvement of inverter arc welding machine is studied and compared the various current control methods with the previous arc reignition current control method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1310-1315
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• 2004

The present study deals with the unique characteristics of hydrogen jet diffusion flames, such as split flames and reignition phenomenon. The split flames are composed of a small flamelet on the nozzle rim and a lifted main flame at downstream. When mass flow rates of fuel reach a critical point, a small-sized flamelet is found to remain in the vicinity of the nozzle exit and the flame reignition subsequent to blowout of main flame occurs repeatedly. In this study, the non-luminous hydrogen jet diffusion flames are visualized by using schlieren technique in order to analyze the combustion characteristics of hydrogen jet diffusion flames with focus on the flame reignition phenomenon.

• 한국추진공학회지
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• 제26권4호
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• pp.64-71
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• 2022

개량된 성능의 상단엔진 개발을 위해 다단연소 사이클 액체로켓엔진의 연구가 진행 중이다. 재점화 기술을 개발하기 위한 수류시험, 점화시험, 연소시험을 계획하여 수행하였다. 재점화 시 터보펌프에서 캐비테이션 현상을 발생시킬 수 있는 연료라인으로의 퍼지가스 유입문제를 해결하기 위해, 각 단계의 시험결과를 분석하였다. 분석결과를 바탕으로 기포제거 밸브의 작동, 퍼지밸브와 엔진 연료밸브의 열림 중첩시간 줄임을 통해 퍼지가스 유입문제를 해결하였다. 이를 바탕으로 재점화 연소시험을 성공적으로 수행하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1856-1858
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• 2000

This paper describes the principles of reignition system which has newly been developed and used as KERI's high power testing facilities. Synthetic short-circuit testing method is generally adopted to perform the short-circuit test of the ultra high-voltage circuit breakers, which consists of two separated sources such as the current source from short-circuit generator and the voltage source from charged energy in capacitor. And, in case of synthetic short-circuit test, it will be necessary to use the reignition system in order to extending the arcing time of the circuit breaker and provide the arc energy equivalent to the direct testing method.

• 대한기계학회논문집
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• 제12권2호
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• pp.328-337
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• 1988

본 연구에서는 전보의 연구를 통해 가장 성능이 우수하다고 평가된 형상의 연소시스템을 선택해서, 연소실의 압력변동과 이온전류변동의 동시측정, 압력변동과 온도변동의 동시측정결과를 신호분석기에 의해 통계처리함으로써 아직까지 이해가 대단히 부족한 재착화 및 연소메카니즘, 그리고 공기유동특성에 관한 물리적 현상을 규명하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.86-89
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• 1991

In recent years, Vacuum Circuit Breaker(VCB) has been widely used to enhance the confidence and at the same time to ease maintenance of waterworks requipment as the power supply breaker of high voltage motor. When making and breaking the sources as VCB the powerful surge voltage, repetitive reignition phenomenon resulted from exceeding inter-pole endurance voltage of CB, has occured. It has transmitted to the winding of motor stator through the cable, and this surge voltage is repeated over and over again before finishing making and breaking action of CB according to cumulation of repetitive reignition surge, motor has become burned in the end. This paper describes surge voltage occuring in making and breaking of VCB as circuit parameters by transient phenonenon and examines closely the variance of peak values, wavefront-length, wavetail-length, when changing inductance and capacitance of a cable. Finally we will expect to protect motor winding breakdown from surge voltage through parallel connection of suitable-size in the motor.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권7호
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• pp.362-368
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• 2006

This paper presents the results of a small capacitive current interruption test for the three types of interrupter which are called 'serial type', 'parallel/separated type' and 'puffer type' according to the arrangement of the thermal expansion chamber and the puffer cylinder. After the preconditioning test the small current interruption capability of the 'puffer type' decreased, on the contrary, that of the hybrid interrupters increased. A number of reignition have been occurred in the 'serial type' hybrid interrupter and the change of small current interruption capability after preconditioning test is mainly influenced by the structure of interrupter. Finally it has been proved that the 'parallel/separated type' hybrid interrupter has the best interruption performance through the verification tests.