PRG Controlling VARI-LITE Equipment Using DMX 512 - Manual (Page 64)

DMX512 R EFERENCE G UIDE
5 6 02.3004.0300.54
Equipment Handling
Lamps
Servicing
• When handling a lamp, hold it by the ceramic base while wearing cotton gloves or finger cots. Do
not touch the glass envelope (bulb). If you touch the glass with bare fingers, wipe off any
fingerprints with alcohol.
• Use care when opening and closing the rear door of the VL2B and VL2C luminaires. Any jarring
of the rear door can undo the optical alignment of the lamp.
Heat
• When lamps are lit, the interior of the luminaires becomes very hot. To aid in the airflow
circulation within the luminaires, after dousing the lamps, wait ten minutes before removing power
to the luminaires. This will provide enough time for the equipment fan to cool off the unit.
Lamp Life
• When operating arc lamps, allow luminaires to operate for at least 3 minutes. It takes about 3
minutes for the fill components (mercury and halogen-metal compounds) in the lamp tubes to
vaporize completely. If the lamps are switched off earlier than 3 minutes, the fill components are
partially vaporized. The inadequately vaporized fill components and the electrode material
(tungsten) are deposited in the areas of the lamp tubes that have remained cool. As a result, the
lamp tubes blacken prematurely and reduce the service lives of the lamps.
• If system will be unattended for more than two hours, luminaire lamps should be doused. Standby
mode should not be used for more than two hours.
• For VL6 luminaires, if lamp is struck, the luminaire should be maintained in a horizontal position
when not in use.
• For arc lamp luminaires, heads should be tilted horizontal before starting lamps. Lamps generate
light by an electrical discharge arc, whereby the electrons from two electrodes excite the fill
components to give off light. Because of the alternating current "position", the electrons are
alternately given off by the two electrodes. When a lamp is set in a vertical position, the halogen-
metal compounds, which determine the color temperature of the lamp, collect at the top end of the
glass envelope. When the lamp is started, color deviations occur since the concentration of halogen
compounds is greater around the top electrode than the bottom electrode. In addition, the fill
components that are difficult to vaporize congeal around the bottom electrode, thereby reducing
lamp life.