Siemens 5-GMI-350 - Page 42

Maintenance
&
Overhaul
Page
39
Troubleshooting
Continued
Possible
Causes
&
Remedies
Symptoms
Problem
6
.
Auxiliary
switch
NC
contacts
3
-
4
are
open
when
breaker
contacts
are
open
.
Check
linkage
and
switch
.
Replace
or
adjust
as
neces
-
sary
.
7
.
Spring
charged
switch
(
LS
2
)
NO
contact
remains
open
after
springs
are
charged
.
Check
and
replace
as
required
.
1
.
Mechanical
failure
of
operating
mechanism
.
Check
and
contact
fac
-
tory
or
authorized
service
shop
.
1
.
Nuisance
or
false
closing
signal
to
secondary
disconnect
contact
13
Check
relay
logic
.
Correct
as
re
-
quired
.
2
.
Closing
coil
(
52
SRC
)
terminal
2
is
shorted
to
ground
.
Check
to
deter
-
mine
if
problem
is
in
wiring
or
coil
.
Correct
as
required
.
1
.
Mechanical
failure
of
operating
mechanism
.
Check
and
contact
fac
-
tory
or
authorized
service
shop
.
1
.
Secondary
control
power
is
de
-
ener
-
gized
or
control
power
fuses
are
blown
.
Correct
as
indicated
.
2
.
Damage
to
wiring
,
terminals
or
con
-
nectors
.
Check
and
repair
as
neces
-
sary
.
3
.
No
tripping
signal
to
secondary
dis
-
connect
contact
1
.
Check
for
con
-
tinuity
and
correct
relay
logic
.
4
.
Secondary
disconnect
contacts
1
or
2
are
not
engaging
.
Check
and
replace
if
required
.
5
.
Failure
of
trip
coil
(
52
T
)
.
Check
and
replace
if
necessary
.
•
Closing
coil
energizes
.
Sound
of
breaker
closing
is
heard
,
but
breaker
contacts
do
not
close
.
Electrical
problem
Nuisance
or
false
close
Mechanical
problem
Circuit
breaker
will
not
trip
Tripping
coil
,
or
solenoid
(
52
T
)
does
not
energize
.
There
is
no
tripping
sound
.
Courtesy of NationalSwitchgear.com