Rockwell Automation 193-EC4 EC4 Current Monitoring Relay User Manual - Manual (Page 40)

Rockwell Automation Publication 193-UM011A-EN-P - September 2010 41
Protective Trip and Warning Functions Chapter 3
Undercurrent Protection Motor current less than a specific level may indicate a mechanical malfunction in
the installation, such as a torn conveyor belt, damaged fan blade, broken shaft, or
worn tool. Such conditions may not harm the motor, but they can lead to loss of
production. Rapid undercurrent fault detection helps to minimize damage and
loss of production.
Undercurrent Warning
The EC4 Current Monitoring Relay will issue a warning with an undercurrent
condition if:
• The current in an of the phases is lower than the current specified for the
corresponding UC Trip Level parameter (Parameter 110 for L1, parameter
113 for L2, & parameter 116 for L3)
• No warning condition already exists
If an undercurrent warning parameter is satisfied, the following will occur:
• The TRIP/WARN LED will flash a yellow blinking pattern depending on
which phase encountered the undercurrent warning condition
–
2 blinks for L1 undercurrent
– 3 blinks for L2 undercurrent
– 4 blinks for L3 undercurrent
• Parameter 15, Warning Status, will change
– Bit 1 will go to "1" for L1 undercurrent
– Bit 2 will go to "1" for L2 undercurrent
– Bit 3 will go to "1" for L3 undercurrent
• Bit 1 in Parameter 21, Device Status, will go to "1"
IMPORTANT In EC4 Current monitoring relays, the Ground Fault warning function
does not include a time delay feature. Once the GF Inhibit Time has
expired, the Ground Fault warning indication is instantaneous.
Table 12 - Undercurrent Setting Ranges
Current Range [A] Min. [A] Max. [A] Default [A]
0.4…2 0.2 2 2
1…5 0.5 5 5
3…15 1.5 15 15
5…25 2.5 25 25
9…45 4.5 45 45
18…90 9 90 90
9…5000 5 5000 45