Ray G. Gibson

Yellow to White: Ceramic Discharge Metal Halide Retrofit Lamps

Abstract A new breed of high-pressure sodium retrofit lamps has evolved utilizing the best of high-pressure sodium and metal halide technologies. These medium wattage ceramic discharge metal halide lamps have brought color and clarity to formerly dreary HPS industrial installations. A comparison of the two lamp technologies, with the intent of addressing both the similarities and differences, is presented. This comparison focuses on some of the physical, electrical, and photometric aspects of these two different, and yet similar, lamp types.

Energy Saving Ceramic Metal Halide Lamps suitable for Probe-Start and Pulse-Start Systems

Abstract Reduction of energy consumption for lighting has received more and more attention as a global effort to preserve our natural resources. In past years, high efficiency pulse-start quartz metal halide (QMH) lamps have gained momentum and have been applied in many new installations. However, over 80 percent of systems installed in the North American (NA) market are probe-start ballasts. The technologically advanced ceramic discharge metal halide (CDM) lamp has emerged in the market having excellent color properties and improved lumen maintenance compared to QMH lamps while limited to operation on pulse-start metal halide ballasts. Furthermore, the existing QMH and CDM lamps are designed to operate at nominal power on these systems, therefore no energy savings can be realized in existing installations. In realizing the future, this paper describes new energy saving medium wattage CDM lamps that can directly retrofit on either probe-start or pulse-start ballasts. The lamps, which operate at 205 watts and 330 watts respectively on 250/400 watt ballasts, can save 18 percent in energy while providing the equivalent mean luminous flux, superior lumen maintenance, greater service life, and enhanced color properties compared to the existing QMH lamps. By utilizing the latest advancements in ceramic arc tube design, the energy saving CDM retrofit lamps can reliability start on probe-start ballasts. Furthermore, the lamps have universal orientation in open fixtures and long life. With significant energy savings and improved lamp features, the energy saving CDM lamps are ideal for existing and new lighting applications.

Medium power ceramic HID lamps; problems and opportunities resulting from low lamp power factor

Development of medium power ceramic discharge metal halide (CDM) lamps for retrofit onto existing magnetic ballasted quartz metal halide (QMH) systems has posed many technical challenges and forced certain design choice trade-offs for operation on systems originally meant for QMH lamps. The electrical root cause for the trade-offs is the lower power factor (Pf) of the CDM lamps compared to the Pf of QMH lamps. This paper explores the basic physics of the arc plasma and how the high CRI and high efficacy CDM lamps necessarily have power factors lower than their quartz counterparts. Two design approaches that manage the low Pf issue are discussed.

Investigations into LFSW Ballast Induced Instabilities in Ceramic Metal Halide Lamps

A brief study of helical instabilities brought about by the interaction between electronic LFSW ballast and ceramic metal halide lamp parameters is described. Ballast parameters investigated were frequency and rise time while lamp parameters were Hg pressure, discharge tube inner diameter, and electrode diameter. It was found that while the Hg pressure has the greatest impact on the occurrence of instabilities, the commutation frequency and rise time are also of significant importance. A proposed modification to the established theory incorporates the influence of LFSW ballast design parameters. The implications for future ceramic lamp/ballast system developments are discussed