VARILITE VL4 Manual page 20

1-6
V *L
ARI ITE®
CONFIDENTIAL
- VL4™ W
L
ASH UMINAIRE
• When handling a lamp, use the ceramic base to hold the lamp. Do not
touch the glass part of the lamp. If you touch the glass part with your
fingers, wipe off the fingerprints with alcohol. Oils contained in the
skin, and therefore the fingerprints, deteriorate the glass when the oils
are heated causing hot spots on the glass. Lamps could explode at
these hot spots.
• On occasion, lamps have exploded. Wear protective glasses whenever
the covers are removed from the head of the luminaire and the lamp is
exposed.
• Use care when opening and closing the rear door of the VL4
luminaires. Any jarring of the rear door can undo the optical alignment
of the lamp.
• In the event that a large quantity of luminaires need to be optically
aligned, wear dark glasses during the alignment procedure to prevent
eye strain. In addition, always operate the lamp in the closed housing.
There is a danger of glare due to high luminance. Also, a high portion
(three to five percent) of the consumed electrical power is given off in
the form of ultraviolet radiation.
• When operating arc lamps, allow luminaires to operate for at least three
minutes. It takes about three minutes for the fill components (mercury
and halogen-metal compounds) in the lamp tubes of 250-, 400- and
600-watt lamps to vaporize completely. If the lamps are switched off
earlier than three 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.
• Luminaire heads should be tilted to the horizontal position before
starting lamps. The lamps generate light in an electrical discharge arc,
whereby the electrons from the 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 the service life of the lamp.
• When system will be unattended for more than two hours, luminaire
lamps should be doused. Otherwise, if system will be unattended for
less than two hours, system can remain in standby.
S M
ERVICE ANUAL
02.9628.0010
7-Oct-97