6
TB MRIK3 12.00 E
3.1.1
Analog input circuits
The protection unit receives the analog input signals of
the phase currents IL1 (B3-B4), IL2 (B5-B6), IL3 B7-B8)
and the current IE (B1-B2), each via separate input
transformers.
The constantly detected current measuring values are
galvanically decoupled, filtered and finally fed to the
analog/digital converter.
3.1.2
AR Information input circuits
With the aid of information inputs unit
MRIK3
decides
whether and when auto-reclosing may take place:
Circuit breaker position (A7)
With input A7 the position of C.B. can be supervised.
When the circuit breaker is closed the auxiliary voltage
is connected to input A7.
Circuit breaker energy (e.g. motor-wound spring-
closed breakers) (A5)
Because the circuit breaker needs a certain time bet-
ween two reclosing-attempts in order to close again, the
ready signal of the C.B. (auxiliary voltage at A5) is
checked before a new auto reclosing takes place. (see
also para. 4.5.8)
External blocking input (A3)
The unit is blocked when applying voltage to A3.
Common point of the inputs (A2)
All listed inputs have a common connection point for
L- or N.
3.1.3
Blocking input
The protection functions adjusted before will be blocked
if an auxiliary voltage is applied to (terminals) D8/E8
(refer to chapter 5.7.1).
3.1.4
External reset input
Please refer to chapter 5.10.
3.1.5
Output relays of
MRIK3
relays
Two relays are equipped with two change-over contacts
and three relays with each one change-over contact for
alarm. Apart from the relay for self-supervision, all pro-
tective functions can be optionally assigned:
•
Relay 1: C1, D1, E1 and C2, D2, E2
•
Relay 2: C3, D3, E3 and C4, D4, E4
•
Relay 3: C5, D5, E5
•
Relay 4: C6, D6, E6
•
Relay 5: Self-supervision C7, D7, E7
All trip and alarm relays are working current relays, the
relay for self supervision is an idle current relay.
The output relays can be assigned to the tripping func-
tions as required.
