User Manual

Rockwell Automation Publication 193-UM002I-EN-P - December 2011 63
Protective Trip & Warning Functions Chapter 3
• Current Imbalance protection is enabled,
• CI Inhibit Time has expired, and
• Current Imbal is equal to or greater than the CI Trip Level for a time
period greater than the CI Trip Delay.
If the relay trips on a Current Imbalance, the:
• TRIP/WARN LED will flash a red 9-blink pattern,
• bit 8 in Trip Status, Parameter 14, will set to “1”,
• bit 0 in Device Status, Parameter 21, will go to “1”,
• Trip Relay contacts will open, and
• outputs will be placed in their Protection Fault State (if so programmed).
CI Inhibit Time, Parameter 49, allows the installer to inhibit a current imbalance
trip from occurring during the motor starting sequence. It is adjustable from
0…250 seconds.
CI Trip Delay, Parameter 50, allows the installer to define the time period for
which a current imbalance condition must be present before a trip occurs. It is
adjustable from 0.1…25.0 seconds.
CI Trip Level, Parameter 51, allows the installer to define the percent current
imbalance which will cause the relay to trip on a Current Imbalance. It is
adjustable from 10…100%.
Current Imbalance Warning
The E3 Overload Relay will indicate a Current Imbalance warning if:
• no warning currently exists,
• Current Imbalance warning is enabled,
• CI Inhibit Time has expired, and
• Current Imbal is equal to or greater than CI Warn Level.
When the Current Imbalance warning conditions are satisfied, the:
IMPORTANT
The Protection Fault State of OUT A and OUT B is defined by:
• OUTA Pr FltState, Parameter 65
• OUTA Pr FltValue, Parameter 66
• OUTB Pr FltState, Parameter 71
• OUTB Pr FltValue, Parameter 72
IMPORTANT
The Current Imbalance inhibit timer starts after the maximum phase of
load current transitions from 0 A to 30% of the device’s minimum FLA
Setting. The E3 Overload Relay does not begin monitoring for a current
imbalance condition until the CI Inhibit Time expires.