Flame Supervision With Uv Flame Detector Qra2; Qra10; Measuring Circuit For Detector Current Measurement - Siemens LME7 Series Basic Documentation

Building Technologies
HVAC Products
4.11 Flame supervision with UV flame detector
QRA2... / QRA4.U / QRA10...
Operation voltage
Mains frequency
Required detector current
Possible detector current
- Operation
Perm. length of detector cable
- Normal cable, laid separately ¹)
¹)
Multicore cable not permitted

4.11.1 Measuring circuit for detector current measurement

UV flame detector QRA...
QRA...
Figure 4: Measuring circuit for QRA...
Legend
A Exposure to light
C Electrolytic condenser 100...470 µF; DC 10...25 V
Microammeter Ri max. 5,000 Ω
M
Caution!
•
Input QRA... is not short-circuit-proof!
Short-circuits X10-06/2 against earth can destroy the QRA... input
•
Simultaneous operation of flame detector QRA... and ionization
probe is not permitted!
Basic Documentation LME7...
4 Technical Data
AC 280 V ±15 %
50...60 Hz ±6 %
Min. 70 µA
Max. 700 µA
Max. 100 m
25/164
CC1P7105en
13.10.2009