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Universal Motor Controller
UMC100-FBP
Technical Description
Earth Fault Protection with CEM11
The earth fault protection function protects the motor and the network against ground current low. During
an earth fault, the motors can reach a dangerous potential above the ground level thus posing a safety
hazard to personnel. The earth faults are mainly caused due to ageing of the insulation, deterioration of
insulation due to sustained or cyclic overloading, moisture or conductive dust. The monitoring of the earth
fault is carried out with the help of the auxiliary device CEM11. The CEM11 device monitors if the sum of
the three phase currents is zero.
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 CEM11 can be connected to one of the multifunction inputs of the UMC. The earth fault signal can be
optionally delayed. It is also possible to suppress the earth fault during the motor start-up phase.
Block Diagram:
CEM11 Signal
Suppress
during
start up
Sample Circuit Diagram:
To use CEM11 with the UMC proceed as follows:
1.
Select the CEM11 model that suits your application needs. There are four different models available
with feed-through holes from 35mm to 10mm.
.
Connect the CEM11 to one of the multifunction inputs DO0, DI1 or DI and 4V DC supply.
3.
Conigure the corresponding multifuncion input as earth fault input. You can select if the earth fault
supervision shall be suppressed during motor start or not.
4.
Optionally a time can be conigured to delay the creation of a fault or warning. It is adjustable from 0.1
to 5.5 s.
5.
Conigure the threshold when an earth fault should be signalled. The threshold can be set directly at
the earth fault monitor (CEM11) itself. See the CEM11 technical manual for further details.
Relevant Parameters:
•
Multifunction Delay Time
UMC100
UMC100-FBP
Ton
&
10 11
13 14
DI0
DI1 DI2 DI3 DI4 DI5
0 V
24 V DC
Earth Fault
Trip / Warning
•
Multifunction Inputs 0,1, or
15
16
17
18
M
- 4 -
3
3
FieldBusPlug / Issue: 11.009
V 6
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