Woodward SEG HighPROTEC MRA4, Device Manual

Page: 47 / 510

Current Transformers (CT)
EN MRA4 04/09 Page 47
L1 L2 L3
IL1
IL3'
IL2
IL3
IL1'
1
X3.
2
3
4
5
6
7
8
9
10
11
12
IL2'
IL1'
Two phase current measurement (V-connection); In secondary = 5 A.
Earth-current measuring via cable-type current transformer ; IGnom secondary = 5 A.
IL3'
MRI4, MCI4, MRA4, MCA4 => terminal markings X3.
IG'
IL1
1A
5A
N
IL2
1A
5A
N
IL3
1A
5A
N
IG
1A
5A
N
Notice!
Warning!
Recommended for isolated or compensated networks
The shielding at the dismantled end of the line has to be put through the cable-type current
transformer and has to be grounded at the cable side.
Connection example Clockwise Rotating Field
Ring Core Type Current
Transformer: Measures the
ground current. (Sum of the
three phase currents). Can
be used for measuring the
earth current in isolated and
compensated networks. The
shield is to be returned
through the ring core current
transformer.