Phasors - GE 469 Manual

5 ACTUAL VALUES
S PHASORS
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To aid in wiring, the tables on the following page can be used to determine if VTs and CTs are on the correct
phases and that their polarity is correct. Problems arising from incorrect wiring are extremely high unbalance
levels (CTs) or erroneous power readings (CTs and VTs) or phase reversal trips (VTs).
To correct wiring, simply start the motor and record the phasors. Using the tables below along with recorded
phasors, system rotation, VT connection type, and motor power factor the correct phasors can be determined.
Note that the phase angle for Va (Vab if delta) is always assumed to be 0° and is the reference for all angle
measurements.
Common problems include: Phase currents 180° from proper location (CT polarity reversed)
GE Power Management
ð
Va PHASOR
ENTER
0.0% AT 0°Lag
ESCAPE
Vb PHASOR
ESCAPE
0.0% AT 0°Lag
MESSAGE
Vc PHASOR
ESCAPE
0.0% AT 0°Lag
MESSAGE
Ia PHASOR
ESCAPE
0.0% AT 0°Lag
MESSAGE
Ib PHASOR
ESCAPE
0.0% AT 0°Lag
MESSAGE
Ic PHASOR
ESCAPE
0.0% AT 0°Lag
MESSAGE
Phase currents or voltages 120 or 240° out (CT/VT on wrong phase)
469 Motor Management Relay
5.3 A2 METERING DATA

5.3.9 PHASORS

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