
63230-507-201A1 Power Meter 750
03/2007 Appendix C—Instrument Transformer Wiring: Troubleshooting Guide
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Table C– 13:Section IV—Case E
Symptoms: 4-Wire Possible Causes
• kW = near 0
• kVA = near 0
• 3-phase average power factor flip-flopping lead and lag
• Voltages, currents, and kVA are normal
• Two CT secondary leads are swapped (A-phase on B-phase terminal, for
example)
• Two PT secondary leads are swapped (A-phase on B-phase terminal, for
example)
NOTE: In either case, the phase input that is not swapped will read normal lagging power
factor.
Table C– 14:Section IV—Case F
Symptoms: 4-Wire Possible Causes
• kW = negative and less than kVAR
• KVAR = negative and close to value expected for kW
• kVA = expected value
• Power factor low and leading
• Voltages and currents are normal
• All three PT lead connections “rotated” counterclockwise: A-phase wire on
C-phase terminal, B-phase wire on A-phase terminal, C-phase wire on B-
phase terminal.
• All three CT lead connections “rotated” clockwise: A-phase wire on B-phase
terminal, B-phase wire on C-phase terminal, C-phase wire on A-phase
terminal.
Table C– 15:Section IV—Case G
Symptoms: 4-Wire Possible Causes
• kW = negative and less than kVAR
• kVAR = positive and close to the value for kW
NOTE: looks like kW and kVAR swapped places
•
kVA = expected value
• Power factor low and lagging
• Voltages and currents are normal
• All three PT lead connections “rotated” clockwise: A-phase wire on B-phase
terminal, B-phase wire on C-phase terminal, C-phase wire on A-phase
terminal.
• All three CT lead connections “rotated” counterclockwise: A-phase wire on
C-phase terminal, B-phase wire on A-phase terminal, C-phase wire on B-
phase terminal.
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