Section 7: Troubleshooting; Introduction - Eaton SBN-508 Instructions For Installation, Operation And Maintenance

Instructional Leaflet
Effective March 2012

Section 7: Troubleshooting

Introduction

Table 16 will help to determine the probable causes of simple
circuit breaker problems and possible corrective actions .
Possible problems associated with the electronic trip unit
are covered in companion publications, IL70C1037H05 and
IL70C1036H06 . If the problem cannot be resolved with the
aid of one or both of these guides, contact the Cutler-Hammer
service center for more in-depth assistance .
Table 16. Circuit Breaker Troubleshooting Guide
Symptom Probable Cause
The circuit breaker trips open Rating plug not installed
(red fault trip indicator button and load current through
is out and/or fault indicator LED the breaker
is lighted) when closed on a
Repeated closing on
load current
transient (in-rush) current
with thermal memory
active
An overload or fault
current condition
Circuit breaker opens Undervoltage release
(fault trip indicator button operates; voltage too low
is not out) or zero
Shunt trip operates
Trip latch is defective
Circuit breaker cannot Shunt trip control signal
be opened remotely, but absent or too low
can be opened locally
Shunt trip is faulty or
improperly installed
Secondary contact wiring
problem
Circuit breaker cannot OPEN pushbutton locked
be opened locally
Faulty mechanism or
main contacts welded
68 EATON CORPORATION www.eaton.com
IB2C12063H03
Corrective Actions
Install rating plug that
corresponds to current sensors
Wait for circuit breaker (and
loads) to cool before re-closing
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 necessary
Inspect latch condition and
engagement before closing;
consult Cutler-Hammer service
center
Check supply voltage exceeds
70% of rated voltage when
signal is applied to shunt trip
Remove front cover; check
voltage supplied to shunt
trip; make sure shunt trip is
seated and retainer snapped
into place. Check for shunt
trip motion; replace shunt
trip if faulty
Make sure electrical pin and
socket connectors are properly
seated in molded plug. Verify
proper wiring
Remove lock
Contact Cutler-Hammer
service center
Instructions for Installation, Operation and
Maintenance of Magnum SB Insulated Case
Low Voltage Power Circuit Breakers
Circuit breaker makes Closing spring not fully
no attempt to close with charged (check SPRING
either local (manual) or CHARGED indicator)
remote controls; springs
do not discharge
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
Circuit breaker cannot be closed Spring release (closing)
remotely (can be closed locally) coil supply voltage low or
spring release faulty
Secondary contact wiring
problem
Spring release closing
coil signal blocked
Circuit breaker cannot be closed Opening and/or closing
locally (but can be closed pushbuttons locked
remotely)
Circuit breaker does not Charging motor supply
recharge electrically but will voltage absent or too low
recharge manually (<85%)
Charging motor faulty
Drawout circuit breaker will not Circuit breaker will not
lever-in fully enter cell (cell
rejection code plate)
Levering-in screw not
in fully DISCONNECT
position at insertion
Levering-in screw in
DISCONNECT position
but not pushed in far
enough
Protective boots covering
stationary disconnects
Shutter jammed or
locked
Charge spring manually; check
voltage to electrical operator;
replace electrical operator if
faulty
Unplug undervoltage release
from mounting deck and retry
closing operation; if OK, check
voltage supply to undervoltage
release (>85%); replace
undervoltage release if faulty
Check reason for lock
Make sure that circuit breaker
is at a position that permits
closure; door is open check that
shutter (door) over the levering
screw is fully closed
Check for presence of an
interlocking scheme (cable
interlock or key interlock);
check to see if interlocked
circuit breaker is CLOSED
Check power supply voltage;
replace spring release if faulty
Make sure electrical pin and
socket connectors are properly
seated in molded plug. Verify
proper wiring
Clear Digitrip 1150 relay
contact
Check reason for lock
Check charging motor electrical
circuit voltage (check under
load)
Replace charging motor
assembly
Circuit breaker ratings do not
correspond to the cassette
requirements
Rotate levering-in screw
counterclockwise to
DISCONNECT position, then
insert breaker fully into
cassette
Push circuit breaker in as far
it will go, cover should be
flush with front of cassette
side plate
Remove boots
Clear problem