Rockwell Automation 193-EC4 EC4 Current Monitoring Relay User Manual - Manual (Page 39)

40 Rockwell Automation Publication 193-UM011A-EN-P - September 2010
Chapter 3 Protective Trip and Warning Functions
Parameter 37, GF Trip Level, allows the installer to define the ground fault
current at which the EC4 Current Monitoring Relay will trip. It is adjustable
from 20.0 mA…5.0 A
Ground Fault Trip Inhibit
Ground faults can quickly rise from low-level arcing levels to short circuit
magnitudes. A motor starting contactor may not have the necessary rating to
interrupt a high magnitude ground fault. In these circumstances it is desirable for
an upstream circuit breaker with the proper rating to interrupt the ground fault.
When enabled, Parameter 89,
GF Trip Inhibit, inhibits a ground fault trip from
occurring when the ground fault current exceeds the maximum range of the core
balance sensor (approximately 10 A). Note: This feature is only available in series
B and later devices.
Ground Fault Warning
The EC4 Current Monitoring Relay will indicate a Ground Fault warning if:
• No warning currently exists
• Ground fault warning is enabled
• GF Inhibit Time has expired
• GF Current is equal to or greater than the GF Warn Level (Series C and
later devices; for a time period greater than the GF Warn Delay)
When the Ground Fault warning conditions are satisfied, the following will
occur:
• The TRIP/WARN LED will flash an amber 4-blink pattern
• Bit 3 in Parameter 15, Warning Status, will go to “1”
• Bit 1 of Parameter 21, Device Status, will go to “1”
Parameter 38, GF Warn Level, allows the installer to define the ground fault
current at which the EC4 Current Monitoring Relay will indicate a warning and
is adjustable from 20 mA…5.0 A.
Parameter 105, GF Warn Delay (Series C and later), allows the installer to define
the time period (adjustable from 0.0…25.0 s) for which a ground fault condition
must be present before a warning occurs.
IMPORTANT The ground fault inhibit timer starts after the maximum phase of load
current transitions from 0 A to 30% of the device’s minimum FLA Setting
or the GF Current is greater than or equal to 50% of the device’s
minimum GF Current setting. The EC4 Current Monitoring Relay does not
begin monitoring for a ground fault condition until the GF Inhibit Time
expires.