• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.10a
• /
• pp.181-183
• /
• 2009

This paper proposes a programmed ignition method of high frequency electronic ballast for metal halide lamp. The method precisely controls the ignition voltage and prevents possible damage of ballast for abnormal lamp operation or lamp failure, also sures the zero voltage switching. This improved performance for igniting the lamp enables reliable product of high frequency ballast because of high efficiency, fast start and no extra ignitor.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.10
• /
• pp.530-535
• /
• 2001

Resonant-type electronic ballast for a metal halide discharge(MHD) lamp is proposed and implemented for 400W MHD lamp. HID lamps have good color rendition, long life and good focusing capability but they have flickers by acoustic resonance when driven at high frequency. A new control method is employed to remove acoustic resonance related instability in HID lamp. By using the amplitude modulation, a spread spectrum effect is employed on the ballast. The control loop of resonant inverter is analyzed and a current is designed. The ballast consists of a power factor controller, an half-bridge resonant inverter, a simple ignitor and an integrator with OP-amps. The experimental results show the good performance as PF 0.93, ballast loss 22W at output 400W and the conducted EMI level is below 60dBuV.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.05a
• /
• pp.213-216
• /
• 2008

U. S. and NATO allies have recently increased their emphasis on reducing the hazards of tactical munitions that contain energetic materials and actively started many investigations on Insensitive munitions(IM) of missile propulsion. All subcomponents of rocket motor should be properly designed and understood to increase IM properties. Insensitive propellant, motor case, ignitor and mitigation devices are important components of IM technologies of rocket motors.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.11
• /
• pp.3676-3685
• /
• 1996

Enhancement of the ignitability was necessary to realize the lean burn engine. The characteristics of multiple-spark capacitor discharge igniter(MSCDI) usefulness of which for lean burn was examined in constant volume combustion chamber and evaluated in spark ignition engine. Noise of MSCDI for engine was restricted by adoption of low voltage control system. It was found that the adaptability for high engine speed was remarkable. Lean limit in engine with MSCDI was extended 10% than conventional coil ignition system. Also maximum brake thermal efficiency was almost enhanced 1%.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.2
• /
• pp.75-83
• /
• 2001

This paper presents the evaluation of combustion characteristics of sing-hole plasma jet ignitions in comparison with conventional spark ignition for variable of swirl velocity. Plasma jet plugs are three types according to ejecting directions : center of chamber, positive and negative swirl flow direction. Experiments are carried out for equivalent ratio 1.0 of LPG-air mixture in a constant volume cylindrical vessel. Not only the flame propagation is photographed at intervals, but the pressure variation in the combustion chamber is also recorded throughout the entire combustion process. The results show that the plasma jet ignitions and spark ignition enhance the overall combustion rate by increasing the swirl velocity. The dependence of the combustion rate swirl velocity leade to the conclusion that the placma jet plug, which ejects plasma jet to the cwnter of combustion chamber is the most desirable ignitor than other plugs.

• Journal of Industrial Technology
• /
• v.29 no.A
• /
• pp.177-182
• /
• 2009

The inductor which is used at low frequency as the main part of magnetic ballast consists of an iron core, a bobbin and coil. The conventional inductor design method is not suitable for the magnetic ballast because it has various variables and is not a unique method for the magnetic ballast. Thus, this paper presents the optimal design method for a lamination type inductor using a magnetic ballast for Metal Halide Lamps. Also, the optimal inductor design method is researched for inductors of dimming ballasts and ignitors that have a gate-triggered structure using a SCR thyristor. By the simulation and experimental results, we showed that the proposed design methods is valid.

• Electrical & Electronic Materials
• /
• v.5 no.1
• /
• pp.111-121
• /
• 1992

본 연구는 Pb( $Co_{1}$3/Nb$_{2}$3/) $O_{3}$-PbTi $O_{3}$-PbZr $O_{3}$계 압전세라믹스의 조성에 따른 착화소자특성과 기계적응력 인가시의 압전열화현상에 대하여 조사하였다. 그 결과 상경계 조성에서 소결밀도, $K_{33}$ 및 출력전압이 최고치를 나타내었으며 능방정계조성에서는 조성의 변화에 따른 소결 및 전기적특성의 변화는 정방정계조성에 비하여 작았다. 기계적 응력 인가시의 압전퇴화현상은 분역의 재배열로 설명할 수 있었다.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1304-1306
• /
• 1996

A regenerative signal amplifying gate driver of self-excited electronic ballast is presented. It can be used for high pressure sodium (HPS) lamp without auxiliary external ignitor. Since the HPS lamp requires very high ignition voltage at start up, the resonant frequency of the circuit must be increased to obtain high voltage oscillations in spite of relatively small resonant current. The presented gate driver amplifies the current of gate drive transformer and raises the gate-source voltage Quickly to turn on the MOSFET switches. Hence, the resonant frequency can be increased more than 100kHz. The HPS lamp used in the simulation and experiment has the rating of 400W input power at 220V input ac voltage source. The experiments show that the resonant frequency is above 150kHz at start up.

• Journal of Korean Institute of Fire Investigation
• /
• v.3 no.1
• /
• pp.38-42
• /
• 2003

There are many origins of fire which are offered by many path, such as cigarette-butt, light of match, playing with fire, arson, and other, in and around wastebasket. Because of above-mentioned thing and the quality of the plastic, it is very difficult to discriminate the difference of burned pattern between in and around wastebasket, between an accidental fire and arson in oder to investigate the point of fire. In this study, the wastebaskets filled up with 2/3 combustibles, and then, in and around wastebasket using the gas lighter by ignitor, and we observe how the fire spread. As a result, if wastebaskets are burned inside the limit 50%, we discriminate the difference of burned pattern between in and around wastebasket. But, if wastebaskets are burned more thant 50%, it is impossible to discriminate the difference of burned pattern between in and around wastebasket.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.1
• /
• pp.1-8
• /
• 2014

The conventional Three-Stage electronic ballast is stable, but Two-Stage electronic ballast has been researching because of efficiency. Three-Stage electronic ballast is consisted of PFC circuit, buck converter, and inverter circuit, but Two-stage is consisted of PFC circuit, Buck-Inverter full bridge circuit. The Buck-Inverter full bridge inverter consists of two half bridge inverters for low frequency switching, and high frequency switching. In the case of street lamp it is far from a lamp to a ballast, the conventional pulsed high voltage ignitor can not turn on the HID lamps because of reduction of ignition voltage. Therefore, it needs to do the research on a resonant ignition to turn on the HID lamps. Therefore, in the Two-Stage electronic ballast which has the resonant tank for ignition, the transient resonant current because of low frequency changing is analyzed, the novel algorithm is proposed to resuce the transient current.