GEK-7303 Low Voltage
Power
Circuit
Breakers
6
TROUBLE
Overheating
Failure
to Trip
AK-2
Breakers
Failure
to
Trip
AK-3
Breakers
False
Tripping
AK-2
Breakers
False
Tripping
AK-3
Breakers
Failure
.
to
Close
and Latch
Burned
Main
Contacts
TROUBLE
SHOOTING
CAUSE
Contacts not aligned.
Contacts
dirty,
greasy
or
coated
with
dark
film;
Contacts
badly
burned
or
pitted.
Current-carrying surfaces
dirty.
Corrosive atmosphere.
Insufficient bus
or
cable capacity.
Bolts and nuts at terminal connections
uot
tight.
Current in excess
of
breaker rating.
Excessive ambient temperature.
Inductive heating;
Travel
of
tripping device does not provide
positive release
gt tripping latch.
Worn
or
damaged
trip
unit
parts.
- Binds in overcurrent
trip
de.vice._
Loose
or
Disconnected Power Sensor
Disconnect Plugs.
Loose
or
Broken Power Sensor Coil
Tap Connections. -
Overcurrent pick
up
too low. _
Overcurrent time setti!)g too
short.
Bind
in
overcurrent trip device.
Captive Thumb Screw
on
Power Sensor
Loose Fail-Safe Circuitry Reverts .
Characteristic to Minimum Setting
and Maximum Time Delay.
Tap Setting Dial on Power Supply
Incorrectly Set.
External Ground Sensor Coil
Improperly Connected.
Binding in attachments preventing
resetting
of
latch.
Latch out
of
adjustment.
Latch
return
spring too weak
or
broken.
Hardened
or
gummy lubricant.
Safety pin left
in push rod.,
Motor burned out.
Faulty control circuit component.
Improper contact sequence
(main contacts
not sufficienUy parted
when
arcing contacts
part).
.
Short.circuit
current
leJel
above
inter-
rupting r.ating
of
breaker.
Loss
of
contact wipe
or
pressure.
·
REMEDY
Adjust contacts.
Clean contacts.
Rep~ace contacts.
Clean
surfaces
of
current-
carrying
parta.
Relocate
or
proVide adequate
enclosure.
Increase
capacity
of
bus
or
cable.
Tighten, but
do not exceed,
elastic
limit
of
bolts
or
fittings.
Check
breaker
application
or
modify
circuit
by
_decreasing load. _
ProVide adequate venWation. -
C~rrect
bus
or
· cable arrangement.
Re-adjust
or
_ replace tripping device.
Replace
trip
unit.
Replace
overcurrent
trip
device.
Tighten
or
Reconnect Disconnect.
Plugs.
Tighten
or
Reconnect Tap Connections.
__
Check application
of
overeurrent
trip
deVice. ·
Check appllcatiOn
of
overcurrent
trip
deVice.
Replace
overcurrent
trip
device.
Tighten Thumb Screw on
Desired
Setting.
Set Dial
to Correspond with Power
Sensor Coi! Tap.
Refer
to
Fig.
40 Page 38
for
Pola_rity
and Connections. Check Continuity
of Shield and Conductors Connecting
the
External
Ground Sensor Coil
Re-align and adjust attachments.
Adjust latch,
~eplace
spring.
Clean bearing
and
latch surfaces,
Remove safety pin,
Replace motor.
,.
-
Replace
or
adjuat faulty device.
Increase
arcing contact wipe. Adjuat
contact sequence by raising
or
lower-
ing
main
movable
contact pivot block.
ReQuires
system
study
and
possible
replacement
With
breaker haVing
ade-
quate interrupting capacity.
Replace
stationary contact
springs
and
dress
. up
or
replace contacts. _
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