Eaton NRX Instruction Manual page 63

Table 7. Circuit breaker troubleshooting guide.
Symptom
The circuit breaker trips open (red fault trip
indicator button is out and/or fault indicator
LED is lighted) when closed on a load current
Circuit breaker opens (fault trip indicator but-
ton is not out)
Circuit breaker cannot be opened remotely,
but can be opened locally
Circuit breaker cannot be opened locally
Circuit breaker makes no attempt to close
with either local (manual) or remote controls;
springs do not discharge
Circuit breaker can't be closed remotely (can
be closed locally)
Circuit breaker can't be closed locally (can be
closed remotely)
Circuit breaker does not recharge electrically
but will recharge manually
Drawout circuit breaker will not lever in
Series NRX with PXR - type RF low voltage power (air) circuit breakers instruction manual MN013002ENH03 September 2016 www.eaton.com
Probable cause
Repeated closing on transient (in-rush) current with
thermal memory active
An overload or fault current condition
Undervoltage release operates; voltage too low or
zero
Shunt trip opens
Trip latch is defective
Shunt trip control signal absent or too low
Shunt trip is faulty or improperly installed
Secondary wiring problem
OPEN pushbutton locked
Faulty mechanism or main contacts welded
Closing spring not fully charged (check SPRING
CHARGED indicator)
If equipped with undervoltage release, undervoltage
release is not energized or is faulty
Circuit breaker locked in OPEN position
Drawout position interlock is operating; levering
screw
Circuit breaker interlocked with another circuit
breaker or device
Spring release (closing) coil supply voltage low or SR
faulty
Secondary contact wiring problem
Opening and/or closing pushbuttons locked
Charging motor supply voltage absent or too low
(<85%)
Charging motor faulty
Cell rejection code plate
Levering-in screw not fully in DISCONNECT position
at insertion
Circuit breaker not pushed into cassette far enough
Protective shutters jammed/locked
Position detent is engaged
Section 8: Troubleshooting
Corrective action
Wait for circuit breaker (and loads) to cool before
reclosing
Use status and fault indicators to help locate and
remove overload or fault condition
Check and correct the UVR supply voltage (85–110%
rated voltage)
Check control signal(s) to shunt trip; correct if neces-
sary
Inspect latch condition and engagement before clos-
ing; consult Eaton
Check supply voltage exceeds 70% of rated voltage
when signal is applied to shunt trip
Check voltage supplied to shunt trip; make sure ST is
seated in its tray; check for ST motion; replace ST if
faulty
Make sure electrical connections are properly made
and verify proper wiring
Remove lock
Contact Eaton
Charge spring manually; check voltage to electrical
operator; replace operator if faulty
Remove left accessory tray containing UVR and retry
closing operation; if OK, check voltage supply to UVR
(>85%); replace UVR if faulty
Check reason for lock
Make sure circuit breaker is at a position that permits
closure; check that shutter door over levering screw is
fully closed
Check for presence of an interlocking scheme (cable
or key); check to see if interlocked circuit breaker is
CLOSED
Check power supply voltage; replace spring release if
faulty
Make sure electrical connections are properly made
and verify proper wiring
Check reason for lock
Check charging motor electrical circuit voltage (under
load)
Replace motor assembly
Breaker rating not compatible with cassette require-
ment
Rotate levering handle counterclockwise to
DISCONNECT position, then insert circuit breaker fully
into cassette
Push circuit breaker in as far as possible
Clear problem
Reset detent system
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