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LEUKOS - The journal of the Illuminating Engineering Society of North America
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The Journal of the Illuminating Engineering Society of North America    Volume 5     Number 3     January 2009

Publisher's data


Editorial:

EMERGING TECHNOLOGIES AND ECONOMIC DOWNTURNS

Articles:

NEW ADVANCEMENTS IN MEDIUM WATTAGE CERAMIC METAL HALIDE LAMPS

JUNMING TU, JOOST VAN DER EYDEN, TOM DE BAERDEMAEKER, JOSEPH WOODS, KEITH GRAHAM, ALEXANDER DUNAEVSKY, AND NANCY CARUSO

A family of medium wattage ceramic discharge metal halide (CDM) lamps operating on magnetic ballasts was introduced several years ago to the North American market. These medium wattage (MW) lamps (175W – 400W) provide excellent color consistency, high color rendering properties, and long life. However, due to tungsten sputtering and evaporation, wall blackening and consequent lumen reduction is inevitable at late life. Moreover, the efficacy for these lamps is typically in the moderate range of 90 lumens per watt. We present the new technically advanced medium wattage ceramic discharge metal halide lamps that operate on new efficient electronic ballasts. The features and performance for these technically advanced MW ceramic lamps are compared with the three existing metal halide lamps; probe-start (also known as switch-start) quartz metal halide lamp, pulse-start quartz metal halide lamp, and the first generation ceramic metal halide lamp. By utilizing new chemical fillings and an optimized arc tube shape, the new MW ceramic metal halide lamps have high efficacy up to 123 lumens per watt, excellent lumen maintenance, and long service life. The typical color rendering index is 90 and the saturated red color index (R9) is 40 or higher. Furthermore, the lamps are compact and suitable for universal operation, which are desirable for improving optical performance and overall fixture efficiency. The lamps are dimmable to 50% of the nominal power. With these new and improved features, the next generation of energy efficient MW CDM lamps is ideal for general lighting applications including outdoor, high bay industry, public spaces, and retail lighting.

RESEARCH METHODS TO AVOID BIAS IN CATEGORICAL RATINGS OF BRIGHTNESS

S.A. FOTIOS AND K.W. HOUSER

This article presents evidence of potential contraction bias in the category rating task associated with the stimulus presentation sequence, response range and response range anchors, and a grouping bias associated with the number of stimuli and response categories. These biases tend to reduce the difference between ratings given to stimuli. It is demonstrated that such bias is sufficient to hide differences in brightness under lighting from lamps of different spectral power distribution but that precautions can be taken to successfully counter the bias. Research methods that can be employed to avoid bias in categorical ratings of brightness are summarized.

FAREWELL TO THE INCANDESCENT LAMP: A RETROSPECTIVE TO RECOUNT, ASSESS, AND HONOR A PASSING TECHNOLOGY

DAVID L. DILAURA

This article gives a recounting of the principle technologies used in the development of the early commercial incandescent lamp. Criteria are proposed to assess whether a lighting technology is disruptive, and an assessment of the incandescent lamp is made in this regard. The development of the Swan and Edison carbon filament lamps is recounted, including the scientific data and previous technologies that were used and the people involved. Early intellectual property issues are discussed and the technological legacy of the incandescent lamp is assessed.

AN APPLICATION OF A RIPPLE CURRENT CANCELLATION TECHNIQUE TO A BOOST POWER FACTOR CORRECTION CIRCUIT FOR ELECTRONIC BALLASTS

M.G. MARITA, A.V. STANKOVIC, AND L. NERONE

In this article the analysis, design, and implementation of a universal input 150- Watt boost power factor correction converter with a ripple current cancellation circuit for lighting industry is presented. A simulation and experimental bench test model of the 150-Watt boost power factor converter with the ripple current cancellation circuit is presented. The results obtained from the simulation and experimental model are presented. The EMI results of the ripple current cancellation circuit are compared with the traditional filtering method used for the EMI suppression on the 150-Watt boost power factor correction converter. Advantages of the proposed ripple current cancellation circuit are discussed.

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