7.1.3 Measuring points for thermocouples in different lamp types. Osram HQI-E 150 W/NDL CL
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• When measuring the outer bulb temperature, corresponding evaluation must consider the radiation (cooling-down curve)
7.1.3 Measuring points for thermocouples in different lamp types
The radiation of the arc tube heats up the thermocouple on the outer bulb above the temperature of the quartz glass on which it is positioned. Because of the low thermal capacity, the thermocouple cools down quickly to the temperature of the quartz glass, after switching off the lamp, and then cools down slowly with the quartz, as shown in Fig. 36 and Fig. 37. The flat part of the cooling curve can be extrapolated back to the switch-off point to ascertain the temperature of the outer bulb during operation.
The measurement must be made under worst case conditions, i.e. for the pinch temperature: base up burning position, for the outer bulb temperature: horizontal burning position (if permitted).
The specific limit values are stated in the Technical
Information.
The measured values are to be ascertained under the worst case conditions.
Both supply voltage and choke impedance influence lamp wattage. A lower choke impedance and higher supply voltage each cause an increase in lamp wattage. As the limit temperatures also increase with increasing lamp wattage, the worst case is to be ascertained at the maximum possible lamp wattage. To cover all possible parameters such as choke impedance, spread of lamp wattage and supply voltage tolerance.
Lamp wattage should be set to approximately 20% above the normal wattage for measurement purposes.
Compliance with the outer bulb temperature is not always sufficient to design a “good” luminaire.
500
T m1 temperature read when switching off, includes additional heating up of the thermocouple by radiation
T m2 extrapolated temperature of the quartz glass when switching off
The operating temperatures of a lamp differ according to the burning position. The worst case operation is the base up burning position for pinch or base edge temperature measurements and the horizontal burning position for the outer bulb temperature measurement, insofar as this is possible with the permitted burning positions.
400
300
Temperature measurement lamps prepared with thermocouples are available from OSRAM on request for a fee.
200
100
0
0 50 100 150 200 cooling time in s
250 300
Fig. 36: Cooling curve for HCI-T 150 W/830 PB in closed luminaire, lamp wattage 180 W
350
°C 530
520
510
500
490
480
470
460
450
440
430
420
410
400
390
380
0
T m1 temperature read when switching off, includes additional heating up of the thermocouple by radiation
T m2 extrapolated temperature of the quartz glass when switching off
5 10 15 20 sec
Fig. 37: Enlarged detail of figure 36
25 30 35
33
7.1.3.1 HCI ® -TC G8.5
Pinch temperature
(in base up burning position)
Outer bulb temperature
(in horizontal burning position)
7.1.3.4 HCI ® -E and E/P / HQI ® E27 and E40
Base edge temperature
(in base up burning position)
Outer bulb temperature
(in horizontal burning position)
34
7.1.3.2 HCI ® -T / HQI ® -T G12
(similar for the HCI ® -TM and HQI ® -TM G22)
Pinch temperature
(in base up burning position)
7.1.3.5 HCI ® -T and TT / HQI ® -T E27 and E40
Base edge temperature
(in base up burning position)
Outer bulb temperature
(in horizontal burning position)
Outer bulb temperature
(in horizontal burning position)
7.1.3.3 HCI ® -TF, GU 6.5
Pinch temperature
(in base up burning position)
Outer bulb temperature
(in horizontal burning position)
7.1.3.6 HCI ® -TX/P
Base edge temperature
(in base up burning position)
Outer bulb temperature
(in horizontal burning position)
7.1.3.7 HCI ® -TS, RX7s, RX7s-24 and HQI ® -TS Fc2
Outer bulb temperature
(in horizontal burning position)
7.1.3.10 HQI ® -T, ≥ 1000 W
Base edge temperature
(in base up burning position)
Outer bulb temperature
(in base up burning position)
Pinch temperature
(in horizontal burning position)
Outer bulb temperature
(in horizontal burning position)
Base edge temperature
(in horizontal burning position)
7.1.3.8 HCI ® -PAR E27
Base edge temperature
(in base up burning position)
7.1.3.11 HQI ® -TS Excellence
Pinch temperature
(in horizontal burning position)
Reflector neck temperature
(in base up burning position)
Reflector edge temperature
(in horizontal burning position)
7.1.3.9 HQI ® -TS long arc and short arc ≥ 1000 W
Pinch temperature
(in horizontal burning position)
Outer bulb temperature
(in horizontal burning position)
Measurement with radiation pyrometry
The temperature limits for lamps where only one burning position is permitted are determined in the allowed burning position.
35
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