74Tc Trip-Circuit Supervision; Overview Of Functions; Structure Of The Function - Siemens 7SR51 Device Manual

Overcurrent protection device
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Supervision Functions

6.5 74TC Trip-Circuit Supervision

6.5
74TC Trip-Circuit Supervision

Overview of Functions

6.5.1
The Trip‑Circuit Supervision function monitors the integrity of the wiring connections between the
protection device and the circuit‑breaker trip coil.
An alarm is issued if the circuit is not complete i.e. an open circuit is detected.
6.5.2

Structure of the Function

The device provides 3 trip‑Circuit supervision function elements. All elements are identical in operation and
independent from each other allowing 3 trip‑circuits to be monitored. This allows trip‑circuit monitoring of
both circuit‑breakers with phase segregated trip coils or circuit‑breakers with a single common trip coil.
1 or more binary inputs can be mapped to 74TCS-n. The inputs are connected into the trip‑circuit such that at
least 1 input is energized when the trip‑circuit wiring is intact. If all mapped inputs become de-energized due
to a break in the trip‑circuit wiring or loss of CB trip supply an output is given after a time delay.
The use of 1 or 2 binary inputs mapped to the same trip‑circuit supervision element (e.g. 74TCS-n) allows the
user to realize several alternative monitoring schemes.
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Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019

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