Rockwell Automation 825-P Modular Protection System for Motors User Manual - Manual (Page 149)

Rockwell Automation Publication 825-UM004D-EN-P - November 2012 149
Testing & Troubleshooting Chapter 11
12. Connect the AC test source current or voltage transformers to the relay
side of the open breaker or contactor.
13. Apply the rated current.
14. If the relay is equipped with voltage inputs, apply rated voltage for your
application.
15. Use the front panel METER VALUES > INSTANTANEOUS METER function or serial
port METER command to verify that the relay is measuring the magnitude
and phase angle of both voltage and current correctly. Take into account
the relay PTR and CTR1 settings and the fact that the quantities are
displayed in primary units.
16. If you are using a core balance current transformer, apply a
single-phase current (A-Phase) as described in Step 11. Do not apply
voltage.
17. Verify that the relay is measuring the magnitude and phase angle of the GF
Current-Core Balance correctly.
The expected magnitude is (Applied Phase Current) • (CTRN). The
expected phase angle is zero.
Figure 48 - Three-Phase Wye AC Connections
NOTE: If voltage transformers are used: Apply the AC voltage signal to the relay side of an open
disconnect block, which is located between the secondary side of the voltage transformer and
the relay.
If the relay is set to accept phase-to-ground voltages (DELTA_Y = Wye): Set current
and/or voltage phase angles as shown in Figure 48.
If the relay is set to accept delta voltages (DELTA_Y = Delta): Set the current and/or
voltage phase angles as shown in Figure 49.
NOTE: If current transformers are used: Apply the AC current signal to the converter’s module
side of an open CT-shorting disconnect block, which is located between the secondary side of
the current transformer and the MCM converter module.
+120°
–120°
V
C
V
B
V
C
V
A
PHROT = ABC
+120°
–120°
PHROT = ACB
V
B
V
A
When setting Phase Rotation = ABC, set angle V
a
= angle I
a
= 0°
set angle V
b
= angle I
b
= –120°
set angle V
c
= angle I
c
= 120°
set angle V
a
= angle I
a
= 0°
set angle V
b
= angle I
b
= 120°
set angle V
c
= angle I
c
= –120°
When setting Phase Rotation = ACB,