OSRAM QUICKTRONIC-M ECG for circular FL 16 mm - Manual (Page 43)

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of T5/ ∅ 16 mm- fluorescent lamps FH ® ...HE and FQ ® ...FO have a very low
thermal output, producing typically between 10 °C and 20 °C temperature
rise. It allows a wide range of ambient temperatures which is covering
almost all applications. If not, adequate measures must be taken in the
luminaire or at the site of installation to improve the thermal balance of the
luminaire.
If the limit temperature is expected to be exceeded for only short periods
(less than one hour, as may be the case in outdoor installations in direct
sunlight), but most of the entire time the operating temperature is below the
maximum recommended value (at night-time, for example), a certain
balance between reduction and extension of service life may be expected.
However, there is no guarantee from our side that this will be the case.
The temperature at the tc point must never be exceeded by more than
10 °C, otherwise the unit is very likely to suffer permanent damage.
ECGs may also suffer permanent damage if they are operated below the
specified minimum temperature. As already mentioned, if the lamps are
also too cold, there will be problems with starting, low luminous flux and a
shift towards the red end of the spectrum.
3.9.2 Control Gaer
Temperatures
For installing ECGs in luminaires, the measuring point temperature tc on
the case is of major importance in any thermal analysis. The maximum
recommended value for the unit and marked on the housing must not be
exceeded in order to reach the service life as specified in the data sheet.
To obtain a safety approval according to EN 60598 for a luminaire, this
temperature limit my be exceeded by up to 5 °C. However, this application
has a reducing effect on the ECG service life.
3.9.2.1 Measuring Point
Temperature tc
According to EN 60598, tc (c stands for case) is the maximum
recommended temperature that may occur at an indicated point on the
ECG (Tc measuring point) during normal operation at rated voltage and
within the specified temperature range.
In practice, the temperature rise of the housing results from the self-heating
of the unit, which in turn results from the power loss and the ambient
temperature of the ECG. This is influenced by the position of the lamp and
the design of the luminaire and is consequently always higher than the
ambient temperature of the luminaire.
Exceeding the maximum recommended tc temperature by a few degrees
drastically reduces the expected service life of the unit. If the temperature
is exceeded by more than 10 °C, a 50 % reduction in service life can be
expected. At 20
°C or more above the maximum recommended
temperature the unit is likely to fail very quickly. The limit temperatures of
various electronic components ,such as transistors, are primarily
responsible for this.