OSRAM QUICKTRONIC INTELLIGENT DIM CFL - Manual (Page 56)

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Why are the light losses so small due to the temperature limitation?
Assuming a luminaire whose inside temperature (= lamp ambient
temperature) is to be lowered from 65 °C to 55 °C. A reduction of
the system power by 20 % is required for this. The diagram shows the
Φ
(T) curves of T5 lamps for 100 % and 80 % system power.
During the transition from the 100 % curve to the 80 % curve and the
lowering of the lamp ambient temperature by 10 °C, the luminous
flux remains roughly the same.
Figure 39: Temperature regulation and relative luminous flux
QTi (DALI)…DIM never stop thinking: Instructions for the ther-
mal coupling of lamp and ECG
Temperature limitation is control engineering in the classical sense
and requires, therefore, a closed control loop: The lamps must be
able to heat the ECG. This is ensured when the ECG and lamps are
housed in the same luminaire space, separated by a reflector if neces-
sary.
If the ECG is mounted outside the luminaire, it cannot exploit the ben-
efits of the thermal managment.
(T) curves of T5 lamps
0
20
40
60
80
100
120
0 10 20 30 40 50 60 70 80
Lamp ambient temperature [°C]
Relative luminous flux [%]
10 0 % system power
80 % system power temperature
regulation
!