• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2446-2452
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• 2009

A Ceramic Metal-halide lamp is achieved by adding multiple metals to a basic mercury discharge. Because the vapor pressure of most metals is very much lower than mercury itself, metal-halide salts of the desired metals, having higher vapor pressures, are used to introduce the material into the basic discharge. The metal compounds are usually polyatomic iodides, which vaporize and subsequently dissociate as they diffuse into the bulk plasma. Metals with multiple visible transitions are necessary to achieve high photometric efficiency and good color. Compounds of Sc, Dy, Ho, Tm, Ce, Pr, Yb and Nd are commonly used. The maximum visible efficacy of a Ceramic Metal Halide lamp, under the constant of a white light source, is predicted to be about 450lm/W. This is controlled principally by the chemical fill chosen for a particular lamp. Current these lamps achieve 130lm/W and these life time are the maximum 16,000[hr]. So factors of performance lower are necessary to improve lamp performance. In this paper, we analyzed factors of performance lower by accelerated deterioration test. The lamp was operated with short duration turn-on/turn-off procedure to enhance the effect due to electrode sputtering during lamp ignition. The tested lamp that was operated with a longer turn-on/off(20/20 minutes) showed blackening, changed distance between electrodes and lowered color rendering & color temperature by losses of Dy at 421.18nm, I at 511nm, T1 at 535nm and Na at 588nm compared with the new lamp.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.123-127
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• 2011

To clarify the relations of optical properties to the main factors responsible for the loss and damage of luminous efficacy, a 20 min turn-on/turn-off test for 2,000 h for a ceramic metal halide lamp is conducted. The corrosion rates of the arc tube wall and electrode are estimated based on thermal stress. Wall blackening is attributed to the tungsten being transported from the hot electrode tips to the relatively cold arc tube wall. Furthermore, the grain boundaries of the arc tube are changed by the degradation. Distortion of the electrode is observed, and the ignition and the driving voltage of the load both increase. Finally, the color rendering index and the color coordinates are changed after the degradation. The luminous flux and the intensity of the luminous distribution are decreased significantly.

• Journal of Industrial Technology
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• v.31 no.B
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• pp.67-73
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• 2011

Ceramic metal halide lamps have been widely used due to long lifetime, high luminous efficiency and good colour rendering. In this paper, we developed dimming control system of electronic ballast for 70W ceramic metal halide lamp by using 1-10V interface. The proposed electronic ballast is consists of EMI filter, Full-wave rectifier, Active PFC, DBI(Dual Buck Inverter), Igniter and control circuit.It enables to supply both low-frequency rectangular wave voltage and current to the lamp by using DBI(Dual Bcuk Inverter) structure. By using 1-10V interface, the system that able to dimming the lamp is demonstrated by P-spice simulation and experimental results.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.75-81
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• 2010

We described the operating principles of two different type of igniters for lightning of Ceramic Metal Halide Lamp(CMHL) and also provide some useful comparisons. One is for magnetic ballast, the other one is for electronic ballast which operates lamp by low-frequency square-waveform. Ignition voltage of lamp depends on the structure of igniter, such as the length and electrical characteristics of cable, which make troubles for ignition in real sites. Therefore, we measured and analyzed ignition voltages from igniters which are used in magnetic and electronic ballast in cables at a distance of 5 meters between a lamp and a igniter to suggests an applicable solution in real sites.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1947-1953
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• 2009

Metal halide (MH) lamps have been largely used due to high luminous efficiency, good color rendering, and long life. Since the metal halide lamps have problems of high ignition voltage and acoustic resonance. Thus, the design of ballast is very difficult for engineers. This paper proposes prototype of electric ballast in order to solve above two problems. The proposed electric ballast is consisted of EMI filter, full wave rectifier circuit, active PFC, DBI(Dual Buck Inverter), dimming circuit and ignitor circuit. The DBI supplies both rectangular voltage and current to the lamp. As the result of the experiment, the acoustic resonance was eliminated and the ignitor circuit was designed to generate high ignition voltage than 5kV. It makes the dimming circuit possible to control the lamp power in range between 230W and 350W.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2262-2267
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• 2010

In order to analyze the reason of wall blackening, which affect the decline of lifetime in a ceramic metal halide lamp, we carried out the deterioration of ceramic tubes by a change in operating conditions with arc tubes of two types of spherical and cylindrical, and we have confirmed the cause of wall blackening through the analysis of element composition and spectrum from SEM/EDS and spectrum analyzer. Wall blackening of tungsten was shown by sputtering from ignition in 20 minute on/off condition and wall blackening from chemical reaction between PCA wall and rare earth halides was shown significantly in a condition without on/off test. Especially, the wall blackening and the decline of luminous flux were reduced by inner convection in spherical type arc tube. Moreover, the color temperature and color coordinate were changed by reduction of emission spectrum of Dy which causes the chemical reaction with PCA wall.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1989-1994
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• 2009

This study purposes are improvement of system (lamp & ballast) efficacy with and optical characteristics through the developed ceramic arc tube. The designed electronic ballast is substituted for conventional magnetic ballast. These electric signal and optical, thermal characteristics through the improving efficacy of lighting system compared with conventional magnetic ballast. properties of lamp by driving method is researching in ballast. Particularly, electronic ballasts, which improved against weakness of Magnetic Ballast, are researching and applying to control of ceramic metal-halide lamp. but One major limitation is the acoustic resonance problem in CMH lamps at high-frequency operation. In order to avoid acoustic resonance, driving frequency decided 21[kHz]. Before discharge in this paper. The PSpice simulation result obtained sufficient voltage gain and the ignition voltage obtained over 3[kV] at 75[kHz]. After discharge, driving voltage obtained approximately 90[Vrms] at 21[kHz].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.219-219
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• 2009

ceramic metal halide lamps are a subset of high intensity discharge lamps so named because of their high radiance These lamps weak ionized plasma in a fire-resisting but light transmissive wrapping by the corridor of current through atomic and molecular vapors. for commercial applications, For commercial applications, the conversion of electric power to light must occur with good efficiency and with sufficient spectral content throughout the visible (380-800 nm) to permit the light so generated to render colors comparable to natural sunlight. the purpose of this paper is to carry out a study on the variation of ageing time(2000 On/Off[hr]) on the performance of 150W CMH lamps. Experimental results show that the blackening by reacting W(tungsten)with I atomic has been created in the arc tube of an ageing lamp(2000 On/Off[hr]), the arc was unstable, and increased a lamp resistance made lamp voltage increases significantly. Also, Color temperature of the ageing lamp was moved by the losses of Ho with Dy atomics and by recombination of Na with I.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.1055-1061
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• 2002

This paper deals with a design and fabrication of an electronic ballast for 70[W] ceramic discharge metal halide lamps. The proposed ballast is composed of a rectifier, an active power factor correction circuit (PFC), a half-bridge inverter, a LC resonant circuit and a microprocessor. The developed ballast also includes a specially designed time circuit which provides reignition signal of lamps. Running frequency of the ballast is .jet at 40[kHz] to avoid acoustic-resonance and flickering. From the experimental results, input power factor and efficiency of the ballast are estimated 99.8[%] and 93.1[%], respectively.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.81-84
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• 2008

1960년대 중반부터 이미 고압 나트륨램프에 사용되어 오던 반투명의 세라믹 재료(Polycrystalline Ceramic Alumina ; PCA)를 기존 메탈핼라이드램프의 석영(Quartz) 발광관에 적용시킨 세라믹 메탈핼라이드(Ceramic Metal Halide ; CMH) 램프는 1995년 처음 소개된 이래 색 제어, 연색성, 광속유지율 등에서 전통적인 석영 메탈핼라이드(Quartz Metal Halide ; QMH)램프보다 우수한 특성을 가지고 있어 저와트급(150W이하)에서 고와트급에 이르기까지 폭넓게 사용되어지고 있으며 현재 국내에서도 이러한 CMH램프의 개발이 진행 중이다. 본 논문에서는 CMH램프의 우수한 특성을 살펴보기 위하여 국외 선진제품에 대한 전기적, 광학적 특성을 살펴보았으며 실험 결과 CMH 램프의 광속유지 율이 기존 QMH 램프보다 우수한 특성을 갖는 것을 확인할 수 있었다.