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CHAPTER 5: SETTINGS
5.11.4 Underpower
UNDERPOWER
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
PATH: SETTINGS
S10 POWER ELEMENTS
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If enabled, once the magnitude of 3Φ total power falls below the Pickup Level for a period
of time specified by the Delay, a trip or alarm will occur. The Underpower element is active
only when the motor is running and will be blocked upon the initiation of a motor start for a
period of time defined by the
used to allow pumps to build up head before the underpower element trips or alarms). A
value of 0 means the feature is not blocked from start. If a value other than 0 is entered,
the feature will be disabled when the motor is stopped and also from the time a start is
detected until the time entered expires. The pickup level should be set lower than motor
loading during normal operations.
For example, underpower may be used to detect loss of load conditions. Loss of load
conditions will not always cause a significant loss of current. Power is a more accurate
representation of loading and may be used for more sensitive detection of load loss or
pump cavitation. This may be especially useful for detecting process related problems.
UNDERPOWER
BLOCK UNDERPOWER
FROM START: 0 s
UNDERPOWER
ALARM: Off
ASSIGN ALARM
RELAYS:
UNDERPOWER ALARM
LEVEL: 2 kW
UNDERPOWER ALARM
DELAY: 1 s
UNDERPOWER ALARM
EVENTS: Off
UNDERPOWER
TRIP: Off
ASSIGN TRIP
RELAYS:
UNDERPOWER TRIP
LEVEL: 1 kW
UNDERPOWER TRIP
DELAY: 1 s
BLOCK ELEMENT FROM START
Range: 0 to 15000 s in steps of 1
Range: Off, Latched, Unlatched
Range: Alarm, Alarm & Auxiliary2,
Alarm & Aux2 & Aux3, Alarm &
Auxiliary3, Auxiliary2, Aux2 &
Aux3, Auxiliary3
Range: 1 to 25000 kW in steps of 1
Range: 1 to 30 s in steps of 1
Range: On, Off
Range: Off, Latched, Unlatched
Range: Trip, Trip & Auxiliary2, Trip &
Aux2 & Aux3, Trip & Auxiliary3
Range: 1 to 25000 kW in steps of 1
Range: 1 to 30 s in steps of 1
settings (e.g. this block may be
5–83
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