Rockwell Automation 592- E300 Overload Relay User Manual - Manual (Page 149)

Rockwell Automation Publication 193-UM015B-EN-P - June 2014 149
Protective Trip and Warning Functions Chapter 5
Table 138 - Under Frequency Trip Level (Parameter 371)
Under Frequency Warning
The E300 Electronic Overload Relay will indicate an Under Frequency warning
if:
• No warning currently exists
• Under Frequency Warning is enabled
• Voltage is present
• Under Frequency Inhibit Time has expired
• The voltage frequency is equal to or less than the Under Frequency
Warning Level
When the Under Frequency Warning conditions are satisfied, the:
• TRIP/WARN LED will flash a yellow 1-long / 5-short blink pattern
• Bit 4 in Voltage Warning Status (Parameter 11) will set to 1
• Bit 1 in Device Status 0 (Parameter 20) will set to 1
• Any relay outputs configured as a Warning Alarm will close
Under Frequency Warn Level
• Under Frequency Warn Level (Parameter 372) allows the user to define
the frequency at which the E300 Electronic Overload Relay will indicate a
warning. It is user-adjustable from 46…65 Hz.
Table 139 - Under Frequency Warn Level (Parameter 372)
Default Value 57
Minimum Value 46
Maximum Value 65
Parameter Type USINT
Size (Bytes) 1
Scaling Factor 1
Units Hz
IMPORTANT The Under Frequency Inhibit Time starts after a phase voltage transitions from
0V to 20V L-L. The E300 Electronic Overload Relay does not begin monitoring
for an under frequency condition until the Under Frequency Inhibit Time
expires.
Default Value 58
Minimum Value 46
Maximum Value 65
Parameter Type USINT
Size (Bytes) 1
Scaling Factor 1
Units Hz