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3.7
CT Polarity (PCU1-SP only)
Figure 3.5 PCU1-SP CT ratio/polarity
3.7.1
Modes & Settings
Timer mode: Off
Auxiliary metering: CT polarity
3.7.2
Connections
Connect current output from
loading unit to busbar through
CT primary (or loop lead
through the CT). Ensure that
CT P2 connects to COM
terminal on loading unit.
Connect S1 & S2 on CT
secondary
to
PCU1-SP
auxiliary metering input S1 &
S2. Check that CT S1
connects to COM input.
3.7.3
Test Procedure
Switch on the main supply
switch.
Set timer mode switch to the
off position.
Ensure that the output control
is in the zero position.
Check that connections are
made as above.
Choose a suitable test current.
The test current must be
greater than 10% of the
metering range in use (e.g.
500A on 100% range with
NLU5000). The CT secondary
current must not exceed 5A.
Press the output on push-
button and increase the output
current to the desired test
current. The display will show
either “OK” for correct polarity
or “REV” for reversed polarity.
Press output off push-button.
