Uv Flame Detectors Qra2 / Qra4 / Qra10 - Siemens LMV36.520A1 Basic Documentation

Measuring circuit for
detector current
measurement
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4.4.2 UV flame detectors QRA2 / QRA4 / QRA10

Caution!
If flame detectors QRA2 / QRA4 / QRA10 are used for flame supervision with the
LMV36..., it must be ensured that the basic unit is permanently connected to
power (conforming to EN 230 / EN 298), thus enabling the system to detect
flame detector failures during startup and shutdown. Generally, the system
works with QRA flame detectors in intermittent operation.
For technical data, refer to Data Sheet N7712 covering QRA2 / QRA10 UV flame
detector!
For technical data, refer to Data Sheet N7711 covering QRA4 UV flame detector!
Operating voltage
Required detector current in operation
Possible detector current in operation
Permissible length of flame detector cable
- normal cable (laid separately)
Threshold values when flame is supervised by QRA...:
- Start prevention (extraneous light)
- Operation
UV flame detector QRA...
QRA...
Legend
A Incidence of light
C Electrolytic capacitor 100...470 µF; DC 10...25 V
Microammeter Ri max. 5000 
M
Warning!

Input QRA... is not short-circuit-proof!
Short-circuits of X10-06 pin 2 against earth can destroy the QRA... input

Simultaneous operation of QRA... and ionization probe is not permitted!
Basic documentation LMV36...
4 Technical data
Max. 350 V peak
Min. 70 µA
Max. 600 µA
Max. 20 m
Intensity of flame (parameter 954) ≥18%
Intensity of flame (parameter 954) >24%
CC1P7544en
25.09.2013