Energy balance of metal halide lamps in quartz and ceramic envelopes

Summary form only given. Energy conservation has accelerated the efforts toward development of compact low wattage metal halide (MH) lamps with warm color temperature as a replacement for incandescent lamps in indoor applications. These technologically advanced MH lamps combine a high efficacy of 85-95 lm/W with a long life of 10-15 thousand hours. Applications require excellent color rendering properties and color consistency comparable to that exhibited by incandescent lamps. The energy balance of MH lamps having discharge envelopes made of quartz and PCA ceramic was studied. The energy balance was obtained by spectral power distribution measurements in the UV, visible and IR spectral regions and by absolute radiometric measurements using a detector with spectrally broad response. The study was conducted at different levels of lamp electrical input power. A linear relationship between total discharge radiated power and input wattage was observed. This relationship was fitted to lamps of different material, shape and chemical fill.