Product description and operating information
Short arc metal-halide lamps are lamps for dc and ac operation in which the discharge arc burns at high pressure
in an atmosphere of halogen and mercury vapor. Short arc metal-halide lamps are available in wattages from 10
W to 18000 W.
When the lamps are in a cold state, in other words at room temperature (21°C), the mercury is generally present
in the form of small metallic droplets in the discharge vessel. When the lamp is started, the mercury vaporizes
as the temperature in the bulb rises and heats up in the arc between the electrodes to around 10,000°C. The
temperature on the inside wall of the bulb is around 800°C. When thermal equilibrium is reached (which may
take from 1 to 10 minutes after the lamp has been switched on, depending on the type of lamp), the mercury
vapour exerts a pressure of up to 200 bar on the bulb, depending on the type of lamp.