Manual MRIK3-C EN
Woodward
DOK-TD-MRIK3-C Rev. A
13
4.1.1
Analog input circuits
The analog input signals of the phase currents I
L1
(B3 - B4), I
L2
(B5 - B6), I
L3
(B7 - B8) and the earth
current I
E
(B1 - B2) are fed to the protection device via separate input CTs. The current measuring
quantities are galvanical decoupled, analogously filtered, and then fed to the analog/digital con-
verter.
For the unit type with earth fault directional features (ER/XR-relay type) the residual voltage from
the open delta winding can directly be connected to A3 and A2.
See chapter 5.6 for voltage transformer connections on isolated/compensated systems (direction
feature of the earth fault element)
4.1.2
Output
relays
The MRIK3-C has 5 output relays. Two of these relays with two change-over contacts and three re-
lays with one change-over contact each are used for signalling. The protective functions can be
freely allocated except of those for the self-supervision relay.
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 relays are operating according to the n. o. principle with the exception of the self-supervision re-
lay, which operates acc. to the n. c. principle.
4.1.3
Digital
inputs
The MRIK3-C has 7 digital inputs with fixed functions. The input functions can be selected free for
each digital input. All inputs have a common reference point: Terminal D8. (See chapter 6.12.4 /
6.12.5) MR – Digital multifunction relays
Terminal Function Code
jumper
C8
Digital Input 1
X6
E8
Digital Input 2
X7
A2
Digital Input 3
X5
A5
Digital Input 4
X4
A6
Digital Input 5
X1
A7
Digital Input 6
X2
A8
Digital Input 7
X3