Siemens GMI Series

Interrupter
/
Operator
Description
Page
9
condenses
on
the
surrounding
vapor
shield
.
Contact
materials
and
configuration
are
optimized
to
achieve
arc
motion
and
to
minimize
switching
disturbances
.
Primary
Disconnects
Figure
13
is
a
side
view
of
the
circuit
breaker
with
a
side
phase
barrier
removed
to
show
details
of
the
primary
dis
-
connects
.
Each
circuit
breaker
has
three
upper
and
three
lower
primary
disconnects
.
Upper
primary
disconnects
are
connected
to
the
stationary
contacts
of
the
vacuum
interrup
-
ters
,
and
the
lower
primary
disconnects
to
the
movable
contacts
.
Each
disconnect
arm
has
a
set
of
multiple
spring
loaded
fingers
that
mate
with
bus
bars
in
the
Metal
-
Clad
switchgear
.
The
number
of
fingers
in
the
disconnect
as
-
sembly
varies
with
the
continuous
and
/
or
momentary
rating
of
the
circuit
breaker
.
Phase
Barriers
Phase
barriers
are
variable
among
GMI
breakers
of
dissim
-
liar
voltage
and
continuous
current
ratings
.
Figure
14
is
a
rear
view
of
a
circuit
breaker
that
shows
the
two
outer
(
phase
to
ground
)
insulating
barriers
.
Some
circuit
breaker
ratings
also
have
inner
barriers
(
phase
to
phase
)
.
These
four
plates
of
glass
polyester
insulating
material
are
attached
to
the
circuit
breaker
housing
and
provide
suitable
electrical
insulation
between
the
vacuum
interrupter
primary
circuits
and
the
housing
.
Figure
14
.
Breaker
with
Insulating
Outer
Phase
Barriers
.
Stored
Energy
Operating
Mechanism
The
stored
energy
operating
mechanism
of
the
GMI
circuit
breaker
is
an
integrated
arrangement
of
springs
,
solenoids
,
and
mechanical
devices
designed
to
provide
a
number
of
critical
functions
.
The
energy
necessary
to
close
and
open
the
contacts
of
the
vacuum
interrupters
is
stored
in
powerful
tripping
and
closing
springs
.
These
springs
are
normally
charged
automatically
,
but
there
are
provisions
for
manual
charging
.
The
operating
mechanism
that
controls
charging
,
closing
and
tripping
functions
is
fully
trip
-
free
,
i
.
e
.
,
spring
charging
does
not
automatically
change
the
position
of
the
Figure
13
.
Upper
and
Lower
Primary
Disconnects
.
There
are
three
insulating
push
rods
.
Each
push
rod
con
-
nects
the
movable
contact
of
one
of
the
vacuum
interrupters
to
the
jack
shaft
driven
by
the
closing
and
tripping
mechanism
.
Flexible
connectors
ensure
secure
electrical
connections
between
the
movable
contacts
of
each
inter
-
rupter
and
its
bottom
primary
disconnect
.
Courtesy of NationalSwitchgear.com