Siemens GMI Series

Interrupter
/
Operator
Description
shaft
assembly
,
and
directly
reflects
the
open
or
closed
position
of
the
breaker
primary
contacts
.
As
the
circuit
breaker
is
racked
into
the
appropriate
position
inside
the
switchgear
,
the
MOC
switch
operating
arm
passes
a
wiring
protective
cover
plate
,
and
engages
the
pantograph
linkage
shown
in
Figure
26
.
Operation
of
the
circuit
breaker
causes
the
pantograph
linkage
to
transfer
motion
to
the
MOC
switches
located
above
the
pantograph
.
The
'
a
'
and
'
b
'
contacts
can
be
used
in
relaying
and
control
logic
schemes
.
All
circuit
breakers
contain
the
MOC
switch
operating
arm
.
However
,
MOC
switches
are
provided
in
the
switchgear
only
when
specified
.
The
breaker
engages
the
MOC
auxiliary
switch
only
in
the
connected
(
operating
)
position
unless
an
optional
test
position
pickup
is
specified
in
the
contract
.
If
a
test
position
pickup
is
included
,
the
breaker
will
engage
the
auxiliary
switch
in
both
positions
(
Figure
26
)
.
Up
to
24
stages
may
be
provided
.
TOC
(
Truck
Operated
Cell
)
Switch
-
Figure
26
shows
the
optional
TOC
cell
switch
.
This
switch
is
operated
by
the
circuit
breaker
as
it
is
racked
into
the
Connect
position
.
Various
combinations
of
'
a
'
and
b
'
contacts
may
be
optionally
specified
.
These
switches
provide
control
and
logic
indication
that
a
breaker
in
the
cell
has
achieved
the
Connect
(
ready
to
operate
)
position
.
Auxiliary
Switch
-
Figure
24
shows
the
breaker
mounted
auxiliary
switch
.
This
switch
provides
auxiliary
contacts
for
control
of
circuit
breaker
closing
and
tripping
functions
.
Con
-
tacts
are
available
for
use
in
relaying
and
external
logic
circuits
.
This
switch
is
driven
by
linkages
connected
to
the
jack
shaft
.
The
auxiliary
switch
contains
both
'
b
'
(
Normally
Closed
)
and
'
a
'
(
Normally
Open
)
contacts
.
When
the
circuit
breaker
is
open
,
the
'
b
'
switches
are
closed
and
the
'
a
'
switches
are
open
.
MOC
(
Mechanism
Operated
Cell
)
Switch
-
Figures
25
and
26
show
the
principal
components
that
provide
optional
control
flexibility
when
operating
the
circuit
breaker
in
the
Test
and
Connected
positions
.
Figure
25
shows
the
MOC
switch
operating
arm
that
projects
from
the
right
side
of
the
circuit
breaker
,
just
above
the
bottom
rail
structure
.
The
MOC
switch
operating
arm
is
part
of
the
jack
Figure
24
:
Auxiliary
Switch
.
Figure
26
:
MOC
and
TOC
Switches
Inside
Switchgear
.
Figure
25
:
MOC
Switch
Operating
Arm
on
Circuit
Breaker
.
16
Courtesy of NationalSwitchgear.com