Welch Allyn Solarc Light - User Manual - Manual (Page 5)

5
Appearance
S ¯olarc lamps contain small amounts of metals. These metals
are in both liquid and solid forms when the lamp is cold.
When cold, these metals may appear to be dark reddish
or reddish-brown in color, can appear as spots or even
a film on the inside surface of the arc tube chamber. This
appearance is normal and, as the lamp warms up, the
metals evaporate and do not interfere with the proper
operation of the lamp.
Warm-up
S ¯olarc lamps take a brief time to come up to full power
after they are turned on (the general rule being about 1
second per watt). For example, a 20 W lamp will take
about 20 seconds to come to normal brightness. Some
amount of instability, i.e., flickering or flashing, is normal
during warm-up and will diminish after the lamp reaches
its thermal equilibrium.
Restart
If power is interrupted to an operating lamp, the pressure
inside the chamber is still very high and the starting pulses
will not be strong enough to form an arc between the
electrodes. The lamp must cool to a point where an arc
can be started. The time required to cool follows our
general rule of about 1 second per watt. (A 10 W lamp
will require about 10 seconds to cool down prior
to restarting.)
Ballast Compatibility
A ballast is the electronic control circuit required to operate
a discharge lamp. S ¯olarc lamps are direct current (DC)
metal halide arc lamps. As such, they are to be operated
with only approved electronic ballasts. In order to start
the lamp, an arc must be struck across the gap formed by
the electrodes. To do this, the ballast generates a series of
very high voltage (~10 kV) and very short (<1 microsecond)
pulses to start the lamp. They can often be heard and
sound like a series of clicks. Again, S ¯olarc lamps are DC
operated and there is a distinct polarity associated with
proper electrical connection. Improper wiring can cause
either lamp or ballast failure.
Operating Orientation
S ¯olarc’s arc is a glowing, heated ball of vapor. Because
heat rises relative to the force of gravity, high-intensity
discharge lamps are sensitive to orientation. S ¯olarc lamps
are designed to be operated in one orientation, usually
horizontal unless otherwise specified. Orienting the lamp
contrary to its original design will cause the thermal
environment to change, thus increasing output variability
and possibly reducing life.
Output Ratings
The industry standard for measuring output of light is the
lumen. Lumen is a measure of the visible light related to
the sensitivity of the human eye. S ¯olarc lamps are generally
designed, built, and characterized using the lumen as the
measure of output and using maintained lumens as the
measure of output over time. Because S ¯olarc lamps produce
full-color light across the entire visible spectrum (UV to
IR), they are often chosen for their unique blue (UV curing)
or red (IR detection) output. Check specifications carefully
to be sure that the lamp is controlled for the light
characteristics you are designing in.
Output Stability
Light output fluctuations are a normal characteristic of
discharge lights. Generally, fluctuations are not objectionable
if they vary no more than 5% at any given time. S ¯olarc
lamps are controlled to have no more than 5% fluctuations
in initial output. Metal halide lamps can also exhibit
occasional flaring, or bright flashes of red or pinkish light.
Flaring occurs as the liquid metals settle into a stable
thermal location within the bulb chamber. Flaring generally
occurs during initial warm-up, if the lamp is jarred, or if it
changes orientation.
Safety
As with any high-power lighting system, it’s important to
remember specific safety issues. The S ¯olarc lamp system
generates a series of high-voltage ignition pulses of
approximately 6 – 10 kV for a short time during each
starting cycle. If a lamp fails to start, those starting pulses
will stop after 2 seconds. Do not switch the light source
from ON to OFF in rapid succession, as this will dramatically
shorten lamp life. We also recommend that each application
be fused in order to protect the product against any
internal failures.
Always allow lamp to cool before replacing. Do not
remove the lamp from equipment until it has cooled
completely. For optimum performance, avoid handling the
bulb or the reflector. Fingerprints or other contaminants
on the glass may result in performance degradation.
S¯olarc LAMP OPERATING CHARACTERISTICS
LAMP SAFETY, HANDLING & DISPOSAL