The operation of TCM can be described by using a module diagram. All the modules in
the diagram are explained in the next sections.
A070785-ANSI V1 EN
Figure 426: Functional module diagram
TCM status
This module receives the trip circuit status from the hardware. A detected failure in the trip
circuit activates the timer.
Timer
Once activated, the timer runs until the set value Trip delay time is elapsed. The time
characteristic is according to DT. When the operation timer has reached the maximum
time value, the ALARM output is activated. If a drop-off situation occurs during the operate
time up counting, the fixed 0.5 s reset timer is activated. After that time, the operation
timer is reset.
The BLOCK input can be controlled with a binary input, a horizontal communication input
or an internal signal of the relay program. The activation of the BLOCK input prevents the
ALARM output to be activated.
6.1.5 Application
TCM detects faults in the electrical control circuit of the circuit breaker. The function can
supervise both open and closed coil circuits. This supervision is necessary to find out the
vitality of the control circuits continuously.
Figure 427 shows an application of the trip circuit supervision function use. The best
solution is to connect an external R
ext
shunt resistor in parallel with the circuit breaker
internal contact. Although the circuit breaker internal contact is open, TCM can see the
trip circuit through R
ext
. The R
ext
resistor should have such a resistance that the current
through the resistance remains small, that is, it does not harm or overload the circuit
breaker's trip coil.
Section 6 1MAC059074-MB A
Supervision functions
836 615 series ANSI
Technical Manual
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