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The color temperature of a metal-halide lamp can also be affected by the electrical characteristics of the electrical system powering the bulb and manufacturing variances in the bulb itself. If a metal-halide bulb is underpowered, because of the lower operating temperature, its light output will be bluish because of the evaporation of mercury ...
Streetlamp with a ceramic metal halide bulb Ceramic metal halide bulb with G12 socket. A ceramic metal-halide lamp (CMH), also generically known as a ceramic discharge metal-halide (CDM) lamp, [1] is a type of metal-halide lamp that is 10–20% more efficient than the traditional quartz metal halide [2] and produces a superior color rendition (80-96 CRI).
A red sticker indicates the lamp is metal halide (MH). A sticker that is half-red and half-white indicates a pulse start metal halide lamp (PSMH). Green is also used on HPS units in Canada. Gray indicates that the fixture is of an LED type.
HID lamps produce different colors of light primarily through the use of various metal additives in the lamp's arc tube and the physics of the gas discharge process. [11] Metal Additives: HID lamps contain an arc tube filled with a mixture of gases, including a noble gas (like xenon). These metal additives are crucial for producing different ...
More than this: HID lamps like the metal halide lamps and high pressure sodium lamps have reduced reliability when operated at high frequencies in the range of 20 – 200 kHz, due to acoustic resonance; for these lamps a square wave low frequency current drive is mostly used with frequency in the range of 100 – 400 Hz, with the same advantage ...
With HMI bulbs, color temperature varies significantly with lamp age. A new bulb generally will output at a color temperature close to 15,000 K during its first few hours. As the bulb ages, the color temperature reaches its nominal value of around 5600 K or 6000 K. With age, the arc length becomes larger as more of the electrodes burn away.
Luminous efficacy can be normalized by the maximum possible luminous efficacy to a dimensionless quantity called luminous efficiency.The distinction between efficacy and efficiency is not always carefully maintained in published sources, so it is not uncommon to see "efficiencies" expressed in lumens per watt, or "efficacies" expressed as a percentage.
Two systems are common: plasma lamps, in which microwaves or radio waves, energizes a bulb filled with sulfur vapor [1] or metal halides, and fluorescent induction lamps, which are like a conventional fluorescent lamp bulb that induces current with an external or an internal coil of wire via electromagnetic induction.