ABB RELION REX640 - Commissioning; Commissioning checklist; Checking installation; Checking power supply

<U
TC1
-Q0
AUX. POWER
-A1
Control +
Control -
IRF
ES
TO
-F1
Figure 31: Motor feeder fail-safe trip circuit principle, example 1
A1 Protection relay
ES Emergency stop
Q0 Circuit breaker (CB)
TO Protection relay trip output
IRF Internal relay fault indication
<U CB undervoltage trip coil
TC1 CB trip coil 1
DCS Distributed process control system
F1 Miniature circuit breaker
In example 1, the fail-safe approach aims at securing motor shutdown via an
emergency switch and in case the control voltage disappears. In case of a
temporary internal relay fault, the circuit breaker is immediately tripped before the
relay recovers from the situation. In case the IRF output relay is directly connected
to the undervoltage trip coil circuit, the output’s performance figures (make and
break values) must be checked.
<U
TC1
-Q0
AUX. POWER
-A1
-F1
Control +
Control -
ES
IRF
DCS
TO
Figure 32: Motor feeder fail-safe trip circuit principle, example 2
A1 Protection relay
ES Emergency stop
Q0 Circuit breaker (CB)
Table continues on the next page
1MRS759142 F Basic functions
REX640
Technical Manual
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