Philips Electromagnetic Lamp Indoor Furnishings User Manual


 
Once ignited, the lamp warms up its surroundings and, after run-up, the
low ambient temperature has less influence on the electrical
performance. Still, the light output varies with the actual tube wall
temperature. Capacitive circuits give less light at low temperatures than
inductive circuits due to the constant-current characteristic of the
capacitive circuit.
2) Gear
The minimum temperature for some electronic components and for
compensating capacitors is -25 ºC.The capacitance of capacitors, for
instance, declines steeply below that temperature. For that reason
gear should be installed at places where the ambient temperature will
not fall below -25 ºC.
3) Luminaires
In general the construction of the luminaires and optics is not affected
by low ambient temperatures down to -25 ºC.Of course plastic parts
such as clips are more brittle at low temperatures and should then be
handled with care.
Maximum temperatures
1) Lamps
For fluorescent lamps the temperature of the glass tube wall is of
prime importance, especially with regard to the applied phosphors. It
will be clear that the actual lamp temperature very much depends on
the luminaire in which the lamps are placed. Lamps must only be used
in luminaires which are constructed for that particular type of lamp.
For some lamp types absolute maximum temperatures of a specified
spot are given (see SL, Fig. 128).With this in mind, also see maximum
and ambient temperatures under point 3) Luminaires.
5
134
Fig. 128.The maximum recommended
ambient temperature at which an SL lamp
can operate is 55 ºC.The part of the lamp
with the highest temperature is a 5 mm
wide section around the circumference of
the housing.The temperature measured in
this region, on the surface of the housing,
is about 150 ºC. Exceeding this
temperature can result in reduction of
lamp life.
3.12 Ambient and operating temperatures
5 mm
warmest region
of the housing