198 Rockwell Automation Publication 193-UM015D-EN-P - February 2015
Chapter 6 Protective Trip and Warning Functions
Frequency Protection
The E300 Electronic Overload Relay has the capability to help protect against
poor voltage quality by offering frequency-based protection. This protection is
used when electric power is provided by stand-alone electric generators. You can
prevent a contactor from energizing if the voltage frequency is either too high or
too low. The E300 Electronic Overload Relay can monitor for this condition
with its Over and Under Frequency Trip and Warning function, and it can detect
for an improper voltage frequency to minimize motor damage and loss of
production.
Under Frequency Inhibit Time
Under Frequency Inhibit Time (Parameter 369) allows you to inhibit an under
frequency trip and warning from occurring during the motor starting sequence. It
is adjustable from 0…250 seconds.
Table 239 - Under Frequency Inhibit Time (Parameter 369)
Over Frequency Inhibit Time
Over Frequency Inhibit Time (Parameter 373) allows you to inhibit an over
frequency trip and warning from occurring during the motor starting sequence. It
is adjustable from 0…250 seconds.
Range
1 = ABC
2 = ACB
Parameter Type USINT
Size (Bytes) 1
Scaling Factor 1
Units
The Phase Rotation Inhibit Time starts after a phase voltage transitions from
0V to 20V L-L. The E300 Electronic Overload Relay does not begin monitoring
for a phase rotation mismatch condition until the Phase Rotation Inhibit Time
expires.
Default Value 10
Minimum Value 0
Maximum Value 250
Parameter Type USINT
Size (Bytes) 1
Scaling Factor 1
Units Seconds
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