Nexus 1250 - Isolating a CT Connection Reversal; Instrument Power Connections

Doc# E107706 4- 7
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4: Electrical Installation
4.7: Isolating a CT Connection Reversal
For a Wye System, you may either:
• Check the current phase angle reading on the meter's external display (see Chapter
6). If it is negative, reverse the CTs.
• Go to the Phasors screen of the Communicator EXT
TM
software (see Chapter 13 in
the Communicator EXT
TM
4.0 and MeterManager EXT Software User Manual for
instructions). Note the phase relationship between the current and voltage: they
should be in phase with each other.
For a Delta System:
• Go to the Phasors screen of the Communicator EXT
TM
software program (see
Chapter 13 in the Communicator EXT
TM
4.0 and MeterManager EXT Software User
Manual for instructions). The current should be 30 degrees off the phase-to-phase
voltage.
4.8: Instrument Power Connections
The Nexus® 1250/1252 meter requires a separate power source.
To use AC power:
1. Connect the line supply wire to the L+ terminal
2. Connect the neutral supply wire to the N- terminal on the meter.
To use DC power:
1. Connect the positive supply wire to the L+ terminal.
2. Connect the negative (ground) supply wire to the N- terminal on the meter.
Power supply options and corresponding suffixes are listed in the table shown on the
next page.