Siemens SIPROTEC 7SD80 Manual page 235

This results in an upper limit for the resistance dimension, R
value of the arithmetic mean R should be selected:
In order that the minimum voltage for controlling the binary input is ensured, R
To keep the circuit breaker trip coil energized in the above case, R
I
BI (HIGH)
V
BI min
V
CTR
R
CBTC
V
CBTC (LOW)
If the calculation has the result R
. This threshold is determined via the parameters 260 Threshold BI 1 to 266 Threshold BI 7 The
V
BI min
settings Thresh. BI 176V, Thresh. BI 88V, Thresh. BI 19V are possible.
For the power consumption of the resistance:
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
Constant current with activated BI ( = 0.25 mA)
Minimum control voltage for BI (= 19 V at delivery setting for nominal voltages of 24
V/ 48 V; 88 V at delivery setting for nominal voltages of 60 V/ 110 V/ 125 V/ 220 V/
250 V)
Control voltage for trip circuit
Ohmic resistance of the circuit breaker coil
Maximum voltage on the circuit breaker coil that does not lead to tripping
< R , the calculation has to be repeated with the next smaller threshold
max min
Mounting and Commissioning
3.1 Mounting and Connections
, and a lower limit R , from which the optimal
max min
is derived as:
max
is derived as:
min
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