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7UM62 Manual
C53000-G1176-C149-3
contact (AuxCont2), to facilitate the detection of a malfunction when the circuit breaker
auxiliary contact (AuxCont1) open and the trip contact has dropped out (see Figure 2-
124). This resistor must be sized such that the circuit breaker trip coil is no longer
energized when the circuit breaker is open (which means AuxCont1 is open and
AuxCont2 is closed). The binary input should still be picked up when the trip contact
is simultaneously opened.
This results in an upper limit for the resistance dimension, R
from which the optimal value of the arithmetic mean should be selected:
R
+
R
max
min
R
=
---------------------------------
2
In order that the minimum voltage for controlling the binary input is ensured, R
derived as:
U
–
U
æ
St
BI min
-------------------------------- -
R
=
è
max
I
BI (High)
So the circuit breaker trip coil does not remain energized in the above case, R
derived as:
U
æ
Ctrl
⋅
-------------------------------------------- -
R
=
R
è
min
TC
U
I
Constant current with BI on (= 1.8 mA)
BI (HIGH)
U
Minimum Control Voltage for BI (= 19 V for delivery setting for
BI min
nominal voltage of 24/48/60 V;
= 88 V for delivery setting for nominal voltage of 110/125/220/250 V)
U
Control voltage for trip circuit
Ctrl
R
DC Resistance of circuit breaker trip coil
TC
U
Maximum voltage on the circuit breaker trip coil that does not lead to
TC (LOW)
tripping
If the result of the calculation is R
next lowest pickup threshold U
set in the device (see Section 3.1.3).
For the power consumption of the resistance:
Example:
I
1.8 mA (from SIPROTEC
BI (HIGH)
U
19 V for delivery setting for nominal voltage of 24/48/60 V (from the
BI min
7UM62)
88 V for delivery setting for nominal voltage of 110/125/220/250 V)
(from the 7UM62)
U
110 V (from system / trip circuit)
Ctrl
500 Ω (from system / trip circuit)
R
TC
U
2 V (from system / trip circuit)
TC (LOW)
ö
–
R
ø
TC
–
U
ö
TC (LOW)
ø
TC (LOW)
< R
the calculation must be repeated, with the
max
min
; for this threshold one or more jumpers must be
BI min
U
æ
2
⋅
-------------------- -
P
=
I
R
=
è
R
R
+
®
7UM62)
Trip Circuit Supervision
, and a lower limit R
max
2
ö
Ctrl
⋅
R
ø
R
TC
,
min
is
max
is
min
259
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