Siemens GMI Series

Overhaul
Replacement
of
Motor
Cut
-
Off
Switch
(
Device
LS
1
)
and
Spring Charged
Switch
(
LS
2
)
-
The
motor cut
-
off
switch
(
LS
1
)
and
spring charged
switch
(
LS
2
)
form
a common
assembly
of
two
switches
on
one
mounting
bracket
.
Should
either switch
require replacement
,
it
is
recommended that both be
replaced
as a
single assembly
.
The
motor
cut
-
off
switch
(
LS
1
)
is
the
"
outboard
"
device
with
respect
to
the
mounting
bracket
.
Re
-
moval
of
the
two
mounting
screws
shown
in
Figure
42
allows
both
switches
to
be
brought
out
for
convenient removal
of
the
interconnecting
wiring
.
Next
,
mark all
wires
to
both switches
.
Remove the wires
.
Then
replace
the
switches
,
rewire
,
and reassemble
the
switches
to
their
mounting
bracket
.
Be
sure
to
use
the
same
flat
washer
,
lock
washer
and
nut
configuration
in
reassembly
as
was
present
in
the
as
-
shipped
condition
.
Replacement
of
Trip
Latch Reset
Check
Switch
(
Device
LS
3
)
-
Note
:
Two
different
latch
systems
have been used
in
GMI
circuit breakers
,
with
changeover
from
one
design
to
the
other
occurring
in
mid
-
1991
.
This
instruction
manual
de
-
scribes
both
designs
.
Pages
10
-
11
describe
the
operation
of
the mechanism
used
beginning
in
approximately
mid
-
1991
.
Pages
12
-
13
describe
the
operation
of
the mechanism
used
from
1989
until
approximately
mid
-
1991
.
Replacement
of
LS
3
-
Mid
-
1991
and
After
The
following
paragraphs
describe
replacement
of
the
trip
latch
reset
switch
for
the
mechanism
used
beginning
in
ap
-
proximately
mid
-
1991
.
An
adjustable
crescent
wrench allows
an
easy
means
of
grasping
the
shelf
and
lifting
it
slightly
to
disengage
the
tabs
in
the
shelf
locating
holes
.
With
the
tabs
disengaged
,
and
grasping
the
top
of
the
spring
,
the whole
assembly
can
be
pulled
forward
.
A
reversal
of
this
procedure
allows
re
-
assembly
.
Note that the
jam jut
at
the lower end
of
the threaded
coupling
rod is located
so
that there
is
0.75
"
thread
engagement
of
the
jack
shaft
.
The
top
nut
above
the
upper
spring
cap
is located
so
that
the
top
surface of
the
spring
cap
is
0.50
"
from
the
end
of
coupling
rod
.
When
re
-
assembling
,
apply
upward
pressure
to
the
shelf
over
stationary
support
and
to
engage
the
shelf
tab
guides
.
The
shelf
may
then be
guided
into
place
.
Replacement
of
Closing
and
Tripping
Solenoids
(
Devices
52
SRC
and
52
T
)
-
Replacement
of
either the
closing
or
tripping
solenoids
is
straightforward
.
Each solenoid has
two
mounting
screws
and
one
quick
disconnect
terminal
.
Removing
the
mounting
bolts
and
quick
disconnect
terminal
of
the solenoid
permits
it
to
slide
out
and
to
be
removed
.
Replacement
requires
careful
insertion
of
the solenoid
and
re
-
attachment
of
the
mounting
bolts
and
quick
disconnect
.
Figure
40
shows the
two
screws
which
attach the close
coil
and
the
quick
discon
-
nect
terminal
for
control leads
.
The
trip
coil
arrangement
is
similar
.
Replacement
of
Anti
-
Pump
Relay
(
Device
52
Y
)
-
Figure
41
helps
illustrate
the anti
-
pump
relay
removal
procedure
.
The
two nuts
holding
the
relay
and its
mounting
bracket
are
removed
.
The
wires connected
to
the
relay
should be
tagged
and disconnected
,
the
relay
and bracket
can
then
be extracted
and
replaced
.
Replacement
of
the
Auxiliary
Switch
-
Figure
41
shows the
auxiliary
switch and its
key
mounting
components
.
Two
mounting
screws
hold the
switch
to
the
mounting
bracket
.
First
remove
the
quick
disconnect terminals
after
marking
their
position
.
The
screw
,
washers
and
nut
connecting
the
switch
'
s
operating
lever
to
the
operating
shaft
is removed
,
and then the
two
mounting
screws
.
Re
-
assemble
in
reverse
order
.
Figure
41
:
Replacement
of
Anti
-
Pump
Relay
or
Auxiliary
Switch
.
Figure
40
:
Replacement
of
Closing
Solenoid
.
28
Courtesy of NationalSwitchgear.com