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HIGH
PRESSURE METAL HALIDE LAMPS
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| General
& Technical Information of Metal |
| Metal
halide lamps, a member of the high-intensity discharge
(HID) family of lamps, produce high light output for their
size, making them a compact, powerful, and efficient light
source. Originally created in the late 1960's for industrial
use, metal halide lamps are now available in numerous
sizes and configurations for commercial and residential
applications. Like most HID lamps, metal halide lamps
operate under high pressure and temperature, and require
special fixtures to operate safely. They are also considered
a "point" light source, so reflective luminaires
are often required to concentrate the light for purposes
of the lighting application.A high-pressure discharge
lamp that is enclosed in a quartz envelope containing
metal halides, usually iodides, and produces high-efficacy
white light. These lamps are widely used for sports stadiums,
roadways, commercial interiors, and industrial applications.
The singular lamp feature is the compact geometry and
high efficacy of nearly white light. The metal halide
lamp requires a high voltage in order to start.These lamps
are always connected to an auxiliary power supply called
the ballast which supplies the proper voltage and current
for starting and operating the lamps. The light output
gradually increases over approximately 2 min as the various
ingredients begin to vaporize and emit light. Special
ingredients can be used inside these lamps to make them
suitable for plant growth, photocopying, and scientific
usages.In cases where a more diffuse light source is desired,
the outer jacket of the lamp can be coated with a white
phosphor in order both to diffuse the light and to change
the color of the output and in some cases actually improve
the efficiency. A cold metal halide lamp cannot immediately
begin producing its full light capacity because the temperature
and pressure in the inner arc chamber require time to
reach full operating levels. Starting the initial arc
sometimes takes a few seconds, and the warm up period
can be as long as five minutes (depending upon lamp type).
During this time the lamp exhibits different colors as
the various metal halides vaporize in the arc chamber.If
power is interrupted, even briefly, the lamp's arc will
extinguish, and the high pressure that exists in the hot
arc tube will prevent re-striking the arc; a cool-down
period of 5-10 minutes will be required before the lamp
can be re-started. |
| DIFFERENT
COLOR : Astra Lighting
Limited offers lamps in many colors to suit virtually
any lighting application. Outlined below are the various
color temperature ( CCT ) currently available: |
| » Warm-white
ww, T < 3300K: Used as a replacement for
very warm incandescent lamps. Used as a generl warm, white
light source, available in clear or coted finish for retail
or intet\rior application: blends with halogen lamps. |
» Neutral
White nw: 3300>T<5000K: Used as a neutral
white light source, available in clear or coated finish
for general lighting, factories, parking lots, warehouse.
A moderately high CCT daylight light source , used in
general and retali lighting applications. |
| » Daylight
dw: T > 5000K: A high CCT daylight source
used to simulate average outdoor light conditions 10,000
- 20,000 K A very CCT, daylight light source, used in
horticulture and aquarium application |
| » Special
Color : Designer color lamps that produce
blue, green, aqua, and pink lightare available for sepcial
applications where color is needed without light loss
due to filters. |
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| PROPER
USE OF METAL HALIDE LAMP :
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Correct
operation and Warnings for High Intensity Discharge
lamp: High
intensity discharge (HID) lamps requir auxiliary equipment
(ballasts, capacitors, ignitors or power supplies) to
provide the correct electrical value for starting and
operating. This auxiliary equipment must meet all electrical
specification outlined by the American National Standards
Institute (ANSI) or IES> Ad\stra lighting limited
will not be responsible for poor performance, personal
injury, property damage, burns or fire from lamps operating
on unapproved equipment.
Power should always be returned off and preferably locked
out in accordance with local guidelines whenever installation,
removal or maintenance is perfomed on lighting systems.
Safety glasses and loves should be used when instralling
or removing HID lamps. Lamps Should be installed firmly
in to appropriate lamp sockets, with out over tightening,
to avoid loosening from vibration.
HID lamps and their arc tubes operate at extremely high
temperature and may shatter as a result of misapplication,
system failure or other factors. Scratches on the outer
bulb, direct contact with water or excessive installation
pressure canalso cause these lamps to break, Breakage
may release extrenemly hot glass and lamp parts in to
the surrounding environment and raise the risk of fire,
personal injury or property damage. Injury may also
be caused by ultraviolet energy from an unjackeeted
HID lamp. If the outer Jacket should break, immediately
turn the power off. Do not remove a lamp until it has
completely cooled the replace it with newAstra lamp.
In areas susceptible of personal injury, users should
seek additional protective measures by using open fixture
(O-rated) lamps and enclosed luminaries.
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Luminaire Requirements and operating
positions : It is imperative that users adhere
to specified luminaire and lamp operating position and
requirements. The operation of a lamp in positions other
than those specified can result in severe reductions
in lamp performance, including lamp life, light output
color. Incorrect operating positions can also create
the possibility of an early failure.
Refer
to each lamp's technical data specification sheet to
determine correct operating position and luminaire requirements.
Also, refer to the diagram in this section to determine
allowable operating position.
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| CAUTION
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Warning ! This
lamp can cause serious skin burn and eye inflammation
from short-wave ultraviolet radiation if outer envelope
of the lamp is broken or punctured and the arc tube
continues to operate. Do not use where people will remain
for more than a few minutes unless adequate shielding
or other safety precautions are used. Lamps that will
automatically extinguish when the outer envelope is
broken or punctured are commerically available."
Careful
adherence to the precautions mentioned above may not
eliminated all possible risks associated with the use
of metal halide lamps, but will reduce the likelihood
of injury or property damage.
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End-of-Life and Reduction of Risk
: At end-of-life, the vast majority of metal
halide lamps will fail simply by not regniting. On rare
occasions, metal halide lamps may fail in a violent
manner. The possibility of this failure is significantly
reduced by group relamaping at or before the rated end
of life, In any application where lamps are operated
continuously (24 hrs/day, seven days/week), the lamps
should always be turned off for a period of at least
15 minutes once a week, a precaution that can reduced
the possibility of violent failures. This procedure
is not required when Astra's open rated, shrouded lamps
are used.
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Starting and Restarting Characteristics
: Probe start metal halide lamps will start
at ambient temperature of -30 C (-22F) or higher. Full
light output does not occur immediately when power is
applied to any metal halide lamp; there is a time delay
of at least two to four minutes after starting for lamps
reach full light output. After lamps have started, a
power interruption 1/4 cycle (1/240th of second) or
more may cause the lamps to extinguish. Several minutes
are required before an arc can be re-established by
the ballast and full light output achieved. The exact
time is dependent on a number of factors including lamp
wattage, ballast and ignitor Characteristics, ambient
temperature, fixture dimensions and supply voltage.
The time needed to establish full light output can be
as short as three minutes and as long as 15 to 20 minutes.
In general, pulse start technology dramatically decreases
the time for hot restart. Astra's exclusive uni-form
pulse start formed body arc tube provides warm-up and
hot restrike in up to 60% less tome and allows better
starting, even down to -40 C (-40F).
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Main Voltage : The
standard operating conditions for the lamp is in an
AC voltage network with supply voltage at 230V/50 HZ.
Some special market lamps have to operate at 400V/ 50
HZ m - supply network. On deviated supply voltage special
ballast with appropriate tap must be used.
Permitted
mains voltage of HPSV lamps is : ± 10%
Metal
halide & HPMV lamps is :
± 3%
Short-term
± 5%
An
increased deviation from above can result in reduced
life time and colour performance.
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Luminous Flux : The
value of luminous flux refers to a vertical burning
position (except lamps for horizontal burning position
only) and operation on reference ballast at rated voltage.
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Colour Characteristics :
It is possible that Metal Halide Lamps due to increase
in voltage fluctuation, burning position, operation
appliance and luminary finish the light colour could
be influenced.
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Safety Regulations : Aatra
High Intensity Discharge Lamps correspond to the safety
regulation in accordance with IEC 60 035.
Astra
Lamps for enclosed fixture finish must be operated in
fixtures with a tightly closed thermal and break safety
glass.
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