How does Metal Halide technology operate?
Metal halide lamps have an efficacy of 60 to 110 lumens per watt and have a warm-up time of 2 to 5 minutes. They have a re-strike time of 10 to 20 minutes. Lamp wattages most commonly range from 175W to 1000W, with the 175W lamp using a 10uf-400Volt Capacitor and the 1000W lamp using a 24uf-480Volt Capacitor, with lamp life of 6,000 to 20,000 hours. Specialty lamps used for sports lighting feature wattages from 1500W to 2000W the 1500W lamp being more common and using a 32uf-525Volt Capacitor, with lamp life ratings of only 3000 to 5000 hours. The advantage of metal halide lighting is its bright, crisp, white light output suitable for commercial, retail, and industrial installations where light quality is important. However, light maintenance over the life of the lamps is less than optimal relative to other HID sources.
The standard arc tube for metal halide lamps has been quartz until the last five to ten years when ceramic arc tube technology was developed. Ceramic arc tubes are predominantly used in low wattage (20 to 150W) lamps, though new designs up to 400W have emerged in recent years. Ceramic arc tubes provide improved constant color over lamp life. This technology is ideal for lamp applications requiring truer color as in fruit, vegetables, clothing, and other accent lighting in retail displays.