Siemens LMV37.400A2 - Flame Detector Specifications; Ionization Probe Details

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Building Technologies Basic documentation LMV37.4... CC1P7546en
HVAC Products 4 Technical Data 01.12.2009
4.4 Flame detectors
4.4.1 Ionization probe
For continuous operation!
No-load voltage at ION terminal
(X10–05 terminal 2)
Approx. U
Mains
Caution!
Protect the ionization probe against electric shock hazard!
Short-circuit current Max. AC 1 mA
Required detector current Min. DC 4 µA, flame display approx. 30%
Possible detector current Max. DC 16…40 µA, flame display
approx. 100%
Max. perm. length of detector cable
(laid separately)
3 m (wire–ground 100 pF/m)
&
Note
With increasing detector cable capacitance (cable length), the voltage at the ionization
probe, and thus the detector current, drops. Long cable lengths plus very highly resis-
tive flames might necessitate low-capacitance detector cables (e.g. ignition cable). In
spite of technical measures taken in the circuitry aimed at compensating potential ad-
verse effects of the ignition spark on the ionization current, it must be made certain
that the minimum detector current required will already be reached during the ignition
phase. If this is not the case, the connections on the primary side of the ignition trans-
former must be changed and / or the electrodes relocated.
ION input
Ionization current in
μ
A
Flame intensity in %
100
90
80
70
60
50
40
30
20
10
0
0 2 4 6 8 10 12 14 16 18 20
7541d46e/0208
Figure 2: Ionization input at AC 120 V / AC 230 V