Siemens SIPROTEC 7UT613 series Manual page 343

7UT613/63x Manual
C53000-G1176-C160-2
Figure 3-2 Logic diagram of the trip circuit supervision using one binary input
TR Trip relay contact
CB Circuit breaker
TC Circuit breaker trip coil
Aux1 Circuit breaker auxiliary contact (make)
Aux2 Circuit breaker auxiliary contact (break)
U Control voltage (trip voltage)
CTR
U Input voltage of binary input
BI
U Voltage across the Bypass resistor
R
R Bypass resistor
This results in an upper limit for the resistance dimension, R
from which the optimal value of the arithmetic mean R should be selected:
In order that the minimum voltage for controlling the binary input is ensured, R
derived as:
So the circuit breaker trip coil does not remain energized in the above case, R
derived as:
I
Constant Current with BI on (= 1.7 mA)
BI (HIGH)
U Minimum control voltage for BI (= 19 V for delivery setting for nominal
BI min
voltage of 24/48/60 V; 73 V for delivery setting for nominal voltage of
110/125/220/250 V)
U Control voltage for trip circuit
CTR
3.1 Mounting and Connections
and a lower limit R
max
,
min
is
max
is
min
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