Rockwell Automation 825-P Modular Protection System for Motors User Manual - Manual (Page 155)

Rockwell Automation Publication 825-UM004D-EN-P - November 2012 155
Testing & Troubleshooting Chapter 11
Periodic Tests (Routine Maintenance)
Due to the 825-P being equipped with extensive self-tests, the most effective
maintenance task is monitoring the front panel messages after a self-test failure.
In addition, review each relay event report generated by a fault. Such reviews
frequently reveal problems with equipment external to the relay, such as
instrument transformers and control wiring.
The 825-P does not require specific routine tests, but your operation standards
can require some degree of periodic relay verification. If you need or wish to
perform periodic relay verification, the following checks are recommended.
Relay Status Verification
Use the front panel STATUS or MPS Explorer software to verify that the relay
self-tests have not detected any WARN or FAIL conditions.
Meter Verification
Verify that the relay is correctly measuring current and voltage (if included) by
comparing the relay meter readings to separate external meters.
Control Input Verification
Using the front panel MAIN > TARGETS > ROW 9 function, check the
control input status in the relay. As the appropriate voltage is applied across input
and input common, its corresponding position in Row 9 changes from zero to
one.
Table 88 - Power Quantity Accuracy — Delta Voltages
Applied Currents and
Voltages Real Power
(kW) Reactive Power
(kVAR) Power Factor
(pf)
PHROT = ABC
Ia = 2.5
∠
–26
Ib = 2.5
∠
–146
Ic = 2.5
∠
+94
Expected:
P =
0.4677 • CTR1 • PTR
Expected:
Q =
0.2286 • CTR1 • PTR
Expected
pf =
0.90 lag
Vab = 120
∠
+30
Vbc = 120
∠
–90
Measured: Measured: Measured:
PHROT = ACB
Ia = 2.5
∠−
26
Ib = 2.5
∠
+94
Ic = 2.5
∠−
146
Expected:
P =
0.4677 • CTR1 • PTR
Expected:
Q =
0.2286 • CTR1 • PTR
Expected:
pf =
0.90 lag
Vab = 120
∠−
30
Vbc = 120
∠+
90
Measured: Measured: Measured: