5–78 469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
Note
Set UNDERVOLTAGE TRIP MODE to “3-Phase”, when the settings S2 SYSTEM SETUP Z
VOLTAGE SENSING
ZV ENABLE SINGLE VT OPERATION is set to “On”. The relay assumes a
balanced three phase system when fed from a single VT.
5.10.2 Overvoltage
PATH: SETTINGS ZV S9 VOLTAGE ELEM. ZV OVERVOLTAGE
If enabled, once the magnitude of either Vab, Vbc, or Vca rises above the pickup level for a
period of time specified by the delay, a trip or alarm will occur (pickup levels are multiples
of motor nameplate voltage).
An overvoltage on running motor with a constant load results in decreased current.
However, iron and copper losses increase, causing an increase in motor temperature. The
current overload relay will not pickup this condition and provide adequate protection.
Therefore, the overvoltage element may be useful for protecting the motor in the event of
a sustained overvoltage condition.
5.10.3 Phase Reversal
PATH: SETTINGS ZV S9 VOLTAGE ELEM. ZV PHASE REVERSAL
OVERVOLTAGE [
OVERVOLTAGE
ALARM: Off
Range: Off, Latched, Unlatched
MESSAGE
ASSIGN ALARM
RELAYS:
Range: Alarm, Alarm & Auxiliary2,
Alarm & Aux2 & Aux3, Alarm &
Auxiliary3, Auxiliary2, Aux2 &
Aux3, Auxiliary3
MESSAGE
OVERVOLTAGE ALARM
PICKUP: 1.05 x
Range: 1.01 to 1.20 x RATED in steps of
0.01
MESSAGE
OVERVOLTAGE ALARM
DELAY: 3.0 s
Range: 0.5 to 60.0 s in steps of 0.1
MESSAGE
OVERVOLTAGE ALARM
EVENTS: Off
Range: On, Off
MESSAGE
OVERVOLTAGE
TRIP: Off
Range: Off, Latched, Unlatched
MESSAGE
ASSIGN TRIP
RELAYS:
Range: Trip, Trip & Auxiliary2, Trip &
Aux2 & Aux3, Trip & Auxiliary3
MESSAGE
OVERVOLTAGE TRIP
PICKUP: 1.10 x
Range: 1.01 to 1.20 x RATED in steps of
0.01
MESSAGE
OVERVOLTAGE TRIP
DELAY: 3.0 s
Range: 0.5 to 60.0 s in steps of 0.1
PHASE [
PHASE REVERSAL
TRIP: Off
Range: Off, Latched, Unlatched
MESSAGE
ASSIGN TRIP
RELAYS:
Range: Trip, Trip & Auxiliary2, Trip &
Aux2 & Aux3, Trip & Auxiliary3
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