Chapter 6—Motor Protection
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
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135
Voltage Unbalance
Voltage Unbalance is estimated using the following equation.
The Voltage Unbalance protection monitors the voltage
unbalance percentage of the supply and will trip the motor if
the voltage exceeds the set threshold. The Voltage
Unbalance protection is active when the motor is in the
energized state. When the Voltage unbalance Start Inhibit
protection is enabled, the Undervoltage protection will
prevent a start into an unbalanced condition as determined
by the Unbalance Start Inhibit Level.
Table 43. Voltage Unbalance
Voltage Phase Loss
The Voltage Phase Loss protection monitors the phase
voltage of the motor and will trip the motor if the voltage falls
below 70% of the nominal mains voltage.
Table 44. Voltage Phase Loss
Fault
Code
Modbus
Fault Action
Delay (Seconds)
Protection
Action
Units
Min.
Max.
Default
Min.
Max.
Default
Modbus
11
Voltage Unbalance
Fault Trip
1043
%
1
20
6
1
60
20
1045
Fault Warning
1044
%
1
20
6
0.2
5
2
1079
Fault
Code
Modbus
Fault Action
Delay (Seconds)
Protection
Action
Units
Min.
Max.
Default
Min.
Max.
Default
Modbus
11
Voltage Phase Loss Fault Trip
1041
%
70
70
70
2
2
2
1042