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Chapter 6—Motor Protection
124
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
www.eaton.com
Voltage Loss Short
The Voltage Loss Short setting is a command to
automatically reclose a contactor to restart a motor in the
event of an undervoltage condition that has exceeded the
VL Auto Time duration, if enabled. A user configurable time
delay is available to prevent out of sync starting of motors.
Time delays for multiple motors monitored by multiple C445
units can be staggered to avoid brownouts from all motors
restarting together based on a common undervoltage
condition.
Operation
Mains voltage dips below the Voltage Loss Level setting for
longer than Auto time. The contactor remains open, and
C445's relay output opens when Auto time expires. If voltage
returns to the Voltage Return Level within the Short Time
setting, C445 will close its relay output to restart the motor
after a specified delay.
Note:
C445 must maintain control power to execute short
time behavior. If the relay powers down, the C445 will
not execute restart logic. See beginning of section for
more information.
Example #3
Main voltage returns above Voltage Return Level setting in
<VL Short Time. Short Delay Time begins counting. Once the
time delay has expired, the contactor is pulled back in and
motor is restarted.
Note:
A run signal must be present for restart to occur. If
there is a run permissive in the circuit, it must also
remain active.
Figure 114. Example #3: Short-Time—Mains Voltage Returns Before Short Time Expires