Functions
254
7UM62 Manual
C53000-G1176-C149-3
2.39
Trip Circuit Supervision
2.39.1 Functional Description
The Multifunctional Protection 7UM62 is equipped with an integrated trip circuit
monitor. Depending on the number of available binary inputs, monitoring with one or
two binary inputs can be selected. If the configuration of the binary inputs needed for
this does not match the selected monitoring type, then a message to this effect
(”
”) is sent. When using two binary inputs, malfunctions in the trip
circuit can be detected under all circuit breaker conditions. When only one binary input
is used, malfunctions in the circuit breaker itself cannot be detected.
Monitoring with
Two Binary Inputs
(not Connected to
Common Potential)
When using two binary inputs, these are connected according to Figure 2-121, parallel
to the associated trip contact on one side, and parallel to the circuit breaker auxiliary
contacts on the other.
A condition for the use of trip circuit monitoring is that the control voltage for the circuit
breaker is greater than the sum of the minimum voltage drops of both binary (U
St
>
2·U
BImin
). Since at least 19 V are needed for each binary input, the monitor can only
be used with a system control voltage of over 38 V.
Figure 2-121 Principle of Trip Circuit Monitor with Two Binary Inputs (not Connected to
Common Potential)
Monitoring with binary inputs not only detects interruptions in the trip circuit and loss
of control voltage, it also monitors the response of the circuit breaker using the position
of the circuit breaker auxiliary contacts.
Depending on the conditions of the trip contact and the circuit breaker, the binary
inputs are activated (logical condition ”H” in Table 2-15), or not activated (logical
condition ”L”).
Even for healthy trip circuits the condition that both binary inputs are not actuated (”L”)
is possible during a short transition period (trip contact is closed, but the circuit breaker
has not yet opened.) A continuous state of this condition is only possible when the trip
circuit has been interrupted, a short-circuit exists in the trip circuit, a loss of battery
voltage occurs, or malfunctions occur with the circuit breaker mechanism.
L
–
L
+
RTC
AuxCont2
Aux
U
BI1
U
BI2
U
St
7UM62
7UM62
TC
CB
Legend:
RTC
— Relay trip contact
CB
— Circuit breaker
TC
— Circuit breaker trip coil
AuxCont1 — Circuit breaker auxiliary contact (NO contact)
AuxCont2 — Circuit breaker auxiliary contact (NC contact)
U
Ctrl
— Control voltage (trip voltage)
U
BI1
— Input voltage for 1st binary input
U
BI2
— Input voltage for 2nd binary input
Note: In the figure the circuit breaker is shown closed.
Cont1
FNo.
FNo.
