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Fault detection and locating
Page 9 of 34
QCA144 1.5 MB/S RPE Cabinet
Maintenance and equipment replacement
Procedure 2
AC BRKR breaker on –48 V rectifier trips
Step
Action
Verification
1
Reset breaker.
If breaker does not trip, fault has cleared.
If fault reoccurs, replace the following
items in the order shown until the fault
clears:
—
The –48 V rectifier
—
The batteries (if equipped)
—
The QBL24 battery box (if equipped)
—
The QUAA3 power unit
—
The QUX19 power unit
—
The QUX20 power unit (if equipped)
2
Disconnect red and black wires from
TB3 at rear of rectifier. Reset breaker.
If breaker trips, replace defective –48 V
rectifier.
3
Set breaker to OFF and reconnect wires.
4
Disconnect red and black wires from
TB1 at rear of QUX19 unit. Reset
breaker.
If breaker trips and no batteries are
provided, the fault is in the red and black
wiring between TB3 of the rectifier and
TB1 of the QUX19 unit. Repair wiring.
5
Set the DC BRKR breaker on the QBL24
battery unit to OFF. Reset breaker.
If breaker trips, replace the QBL24
battery box. If breaker does not trip,
replace the batteries.