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4 SETPOINT PROGRAMMING
4.10 S9 VOLTAGE ELEMENTS
S UNDERVOLTAGE
S [ENTER] for more
The U/V ACTIVE ONLY IF BUS ENERGIZED setpoint may be used to prevent nuisance alarms or trips when the bus
is not energized. If this setpoint is programmed to "Yes", at least one voltage must be greater than 20% of the
nominal nameplate voltage rating for any alarm/trip. If the load is high inertia, it may be desirable to trip the
motor off-line or prevent it from starting in the event of a total loss of line voltage. Programming "No" for this set-
point ensures that the motor is tripped and may be restarted only after the bus is re-energized.
If the undervoltage alarm or trip feature is enabled, once the magnitude of either Va, Vb, or Vc falls below the
pickup level while running or starting pickup level while starting (for a period of time specified by the delay), a
trip or alarm will occur (pickup levels are multiples of motor nameplate voltage). The running pickup level also
applies when the motor is stopped and the U/V ACTIVE ONLY IF BUS ENERGIZED setpoint is programmed to "No".
An undervoltage on a running motor with a constant load results in increased current. The relay thermal model
typically picks up this condition and provides adequate protection. However, this setpoint may be used in con-
junction with the time delay to provide additional protection that may be programmed for advance warning by
tripping.
Attempting to start a large motor when the supply voltage is already down may also be undesirable. An under-
voltage of significant proportions that persists while starting a motor may prevent the motor from coming up to
rated speed. This may be especially critical for a synchronous motor. This feature may be used in with a time
delay to provide protection for undervoltage conditions before and during starting.
GE Power Management
ð
U/V ACTIVE ONLY IF
ENTER
BUS ENERGIZED: No
ESCAPE
UNDERVOLTAGE
ESCAPE
ALARM: Off
MESSAGE
ASSIGN ALARM RELAYS:
ESCAPE
Alarm
MESSAGE
UNDERVOLTAGE ALARM
ESCAPE
PICKUP: 0.85 x RATED
MESSAGE
STARTING U/V ALARM
ESCAPE
PICKUP: 0.85 x RATED
MESSAGE
UNDERVOLTAGE ALARM
ESCAPE
DELAY: 3.0 s
MESSAGE
UNDERVOLTAGE ALARM
ESCAPE
EVENTS: Off
MESSAGE
UNDERVOLTAGE
ESCAPE
TRIP: Off
MESSAGE
ASSIGN TRIP RELAYS:
ESCAPE
Trip
MESSAGE
UNDERVOLTAGE TRIP
ESCAPE
PICKUP: 0.80 x RATED
MESSAGE
STARTING U/V TRIP
ESCAPE
PICKUP: 0.80 x RATED
MESSAGE
UNDERVOLTAGE TRIP
ESCAPE
DELAY: 3.0 s
MESSAGE
469 Motor Management Relay
4.10 S9 VOLTAGE ELEMENTS
Range: No, Yes
Range: Off, Latched, Unlatched
Range: Alarm, Alarm & Auxiliary2, Alarm & Aux2 & Aux3,
Alarm & Auxiliary3, Auxiliary2, Aux2 & Aux3, Auxiliary3
Range: 0.60 to 0.99 x RATED, step 0.01
Range: 0.60 to 0.99 x RATED step 0.01, Off
Range: 0.0 to 60.0 sec., step 0.1
Range: On, Off
Range: Off, Latched, Unlatched
Range: Trip, Trip & Auxiliary2, Trip & Aux2 & Aux3,
Trip & Auxiliary3
Range: 0.60 to 0.99 x RATED, step 0.01
Range: 0.60 to 0.99 x RATED step 0.01, Off
Range: 0.0 to 60.0 sec., step 0.1
4.10.1 UNDERVOLTAGE
4-63
4
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