Woodward highprotec MRI4, User Manual

Page: 53 / 727

Installation and Connection
53 MRI4 DOK-HB-MRI4-2E
L1 L2 L3
IL1
IL3'
IL2
IL3
IL1'
1
X?.
2
3
4
5
6
7
8
9
10
11
12
IL2'
IL1'
Two phase current measurement (Open Delta); In secondary = 5 A.
Earth-current measuring via cable-type current transformer ; IGnom secondary = 5 A.
IL3'
IG'
IL1
1A
5A
N
IL2
1A
5A
N
IL3
1A
5A
N
IG
1A
5A
N
Warning!
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 .
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.
IG meas = IG
IG calc = IL1 + IL2 + IL3