Siemens SIPROTEC Manual page 499

Figure 3-2
TR
CB
TC
Aux1
Aux2
U-CTR
U-BI
R
UR
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 not energized in the above case, R
I
BI (HIGH)
U
BI min
U
CTR
R
TC
U
CBTC (LOW)
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
Principle of the trip circuit supervision with one binary input
Trip relay contact
Circuit breaker
Circuit breaker trip coil
Circuit breaker auxiliary contact (NO contact)
Circuit breaker auxiliary contact (NC contact)
Control voltage for trip circuit
Input voltage of binary input
Bypass resistor
Voltage across the bypass resistor
Constant current with activated BI ( = 1.8 mA)
Minimum control voltage for BI
17 V for delivery setting for nominal voltages of 24/48/60 V;
73 V for delivery setting for nominal voltages of 110/125/220/250 V;
154 V for delivery setting for nominal voltages of 220/250 V
Control voltage for trip circuit
DC resistance of circuit breaker trip coil
Maximum voltage on the circuit breaker trip coil that does not lead to tripping
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
499