Woodward MRM4, Manual

Page: 41 / 460

Installation and Connection
The current measuring inputs may exclusively be connected to current
measuring transformers (with galvanic separation).
CT secondary circuits must always to be low burdened or short-circuited
during operation.
For current and voltage sensing function external wired and appropriate
current and voltage transformer shall be used, based on the required input
measurement ratings. Those devices provide the necessary insulation
functionality.
All current measuring inputs can be provided with 1 A or 5 A nominal.
Make sure that the wiring is correct.
Current Transformer Connection Examples
EN MRM4 01/11 Page 41
L1 L2 L3
IL1
IL2
IL3
1
X3.
2
3
4
5
6
7
8
9
10
11
12
Three phase current measurement; In secondary = 5 A.
IL1
1A
5A
N
IL2
1A
5A
N
IL3
1A
5A
N
IG
1A
5A
N
IL2'
IL3'
IL1'
IG calc = IL1 + IL2 + IL3 = IG