Phase Reversal; Vt Fuse Fail - GE 339 Instruction Manual

CHAPTER 6: SETPOINTS

Phase reversal

VT fuse fail

339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
The 339 can detect the phase rotation of the three phase voltages. When all three Phase
to Phase Voltages (Vab, Vbc and Vca) are greater than 50% of the Motor Rated Voltage, if
the phase rotation of the three phase voltages is not the same as the Supply Rotation
setpoint, and there is no fuse failure, either an alarm or a trip and a Start Inhibit will occur
within 100ms.
PATH:
SETPOINTS > S3 PROTECTION > PHASE REVERSAL
PHASE REVERSAL
Range: Disabled, Alarm, Trip
Default: Disabled
Sets the Phase Reversal action.
Figure 33: Phase Reversal Protection logic diagram
SETTI G
Supply Rotation
Vab
Vbc
Phase Reversed
Vca
LOGIC OPERA D
Fuse Fail
ACTUAL VALUE
Vab > 50% x Rated
AND
Vbc > 50% x Rated
Vca > 50% x Rated
SETTI G
Phase Reversal
= Disabled
= Alarm
= Trip
MOTOR STATUS
Running
KEYPAD RESET
I PUTS
Emergency Restart Input
Lockout Reset Input
Reset Input
SETTI GS
S4 CO TROLS
Emergency Restart
Off = 0
Lockout Reset
Off = 0
Reset
Off = 0
If one or two of the three phase to phase voltages drops to less than 70% of nominal, and
at the same time any of the three voltages is greater than 85%, either an alarm or a trip
and Start Inhibit will occur after a 1 second delay. The 70% threshold allows for the
possibility that the voltage downstream from a blown fuse is pulled up above zero by
devices connected between the open fuse and another phase.
PATH: SETPOINTS > S3 PROTECTION > VT FUSE FAILURE
FUSE FAIL FUNCTION
Range: Disabled, Alarm, Trip
Default: Trip
Sets the Fuse Fail action.
0.1 s
AND
0
AND
AND
AND
S3 PROTECTION
LOGIC OPERA D
PH Reversal Alarm
AND
Any Alarm Op
TARGET MESSAGE
PH Reversal Alarm
State: Operate
PH Reversal Trip
State: Operate
AND S
LOGIC OPERA D
PH Reversal Trip
LATCH
Any Trip Op
R
Set Dominant
LOGIC OPERA D
AND
PH Rvrsl Inhibit
Any Start Inhibit
OR
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