Improved Starting of the 100-W Metal Halide Lamp

Zaslavsky, G.; Cohen, Sheppard; Keeffe, W.M.

doi:10.1080/00994480.1990.10747966

Cited by 16 publications

(9 citation statements)

References 2 publications

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“…The cold fill of HID lamps consists of tens to a few hundreds of Torrs of rare gases, typically Ar, with doses of metal halide additives and/or mercury having a few milliTorrs vapour pressure at room temperature. In the steady state, HID lamps operate as thermal arcs producing quasi-continuum radiation from a multi-atmosphere, metal vapour plasma [1][2][3][4][5]. 3 Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Avalanche process in an idealized lamp: II. Modelling of breakdown in Ar/Xe electric discharges

Bhoj¹,

Kushner²

2004

J. Phys. D: Appl. Phys.

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The breakdown phase of the startup of metal halide lamps is typically through a cold fill of a rare gas and the ambient vapour pressure of a dose of metals. The dynamics of the breakdown stage are of interest for improving the efficiency and lifetime of lamps. A computational investigation of the breakdown of Ar/ Xe mixtures in an idealized lamp geometry was performed using global and two-dimensional (2-d) models to provide insight into the lamp ignition processes and to facilitate comparison with experiments. The experimental trends for breakdown for pressures of 10-90 Torr were qualitatively captured with the global model. Quantitative agreement required accounting for the temporal and spatial plasma dynamics included in the 2-d model. Small fractions of Xe in Ar were found to decrease the breakdown time as the ionization rates increased due to the lower ionization potential of xenon, while the electron energy distribution was not significantly affected. With higher Xe fractions the electron temperature in the ionization front decreased due to there being larger momentum transfer and inelastic losses to the Xe, and as a result the breakdown times increased. The compression of voltage ahead of the ionization front produced large electric fields at the cathode that enabled significant contributions to ionization by secondary electrons.

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Section: Introductionmentioning

confidence: 99%

Avalanche process in an idealized lamp: II. Modelling of breakdown in Ar/Xe electric discharges

Bhoj¹,

Kushner²

2004

J. Phys. D: Appl. Phys.

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“…Metal-halide lamps typically operate in the steady state as multi-atmosphere thermal arcs through a vapour provided by doses of mercury and metal halides [1][2][3][4][5][6][7][8]. The cold fill of the lamp is usually 10-100 Torr of a rare gas and the room temperature vapour pressure of the dose.…”

Section: Introductionmentioning

confidence: 99%

Avalanche processes in an idealized lamp: I. Measurements of formative breakdown time

Moss

Eden

Kushner

2004

J. Phys. D: Appl. Phys.

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Electrical breakdown of cold (room temperature) metal-halide arc lamps typically occurs through the fill of a rare gas (at a pressure of tens of Torrs) and the vapour produced by the metal donor. Restarting a warm lamp is often made difficult by the high pressure of the metal and metal-halide vapours. To reliably start cold lamps with a minimum voltage and a minimum sputtering of the electrodes, and to restart warm lamps that have a high pressure of the metal and metal-halide vapours, auxiliary sources of ionization are often used. As a point of departure for the study of these processes, measurements of formative breakdown times were made in a cylindrical discharge tube resembling a compact polycrystalline alumina envelope metal-halide lamp. Breakdown times were measured for Ar/Xe gas mixtures at total pressures of 10-90 Torr and biases up to 2 kV applied to a 1.6 cm gap. The data provide a knowledge base for a companion computational investigation. We found that breakdown times generally decreased with small admixtures of Xe in Ar (5-15%) and increased with larger admixtures. We attribute these trends to the changing shape of the tail of the electron energy distribution.

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“…This shortcoming limits metal halide lamps from some applications that require fast starting. In the literature, the transient duration is shown to vary with the current applied to a lamp [5,6]. When an electronic ballast with a higher starting current is required, it is essential to use components of higher current and voltage ratings, consequently increasing the production cost.…”

Section: Introductionmentioning

confidence: 99%

Starting Transient Characteristics of Metal Halide Lamps

Tang

Chen

Lee

et al. 2007

2007 Power Conversion Conference - Nagoya

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This paper aims at investigating the effects of the lamp current and power on the electrical behavior, the spectral distribution and the produced luminance. Based on the results observed, the starting transient characteristics can be well understood and the times for entering thermal equilibrium and the steady-state light output can be defined in a more reasonable manner. Experimental evidence shows that the glow-to-arc transition stage takes most of the transient period, and the starting time of a metal halide lamp can be effectively shortened by increasing the lamp current during the glow-to-arc transition stage. More importantly, a specifically-regulated operating power enables the lamp to further enhance luminance, and hence to reduce the starting transient period remarkably.Index Terms --Metal halide lamp, electronic ballast, starting transient.I.

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Improved Starting of the 100-W Metal Halide Lamp

Cited by 16 publications

References 2 publications

Avalanche process in an idealized lamp: II. Modelling of breakdown in Ar/Xe electric discharges

Avalanche process in an idealized lamp: II. Modelling of breakdown in Ar/Xe electric discharges

Avalanche processes in an idealized lamp: I. Measurements of formative breakdown time

Starting Transient Characteristics of Metal Halide Lamps

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