Earth Fault - ABB UMC22-FBP Technical Description

Universal Motor Controller UMC22-FBP
Software version 4.0
V 6
Chapter 3.5~1

3.5 Earth fault

The CEM11 device monitors if the sum of the currents fl owing through it is zero. It can be used in motor
feeders to detect leakage currents respectively ground faults caused for example by insulation break-
downs.
Detection of such ground faults can be
- used to interrupt the motor to prevent further damage, or
- to alert the maintenance personnel to perform timely maintenance.
The following fi gure shows how the earth fault sensor CEM11 can be connected to the UMC22.
UMC22
SW version 5
DIN rail mounting unit
(also possible:
mounting with screws)
CEM11:
Earth Leakage Monitor
(with current transformer)
through-hole diameter:
20 mm / 35 mm / 60 mm
Fig. 3-9: UMC22 with connected earth fault monitor CEM11
FieldBusPlug / Issue: 02.2008
L1, L2, L3
1 2 3 4
- 29 -
UMC22:
+24 V supply output
digital input (n/c contact)
with selectable delay time:
DI2
(CEM11 output is good
for 24 V digital inputs
that meet IEC61131 part 2)
CEM11:
adjustment of the
current threshold
terminals
1: 24 V DC supply
2: Signal output
UMC22-FBP