Siemens GMI Series - Page 33

Maintenance
&
Overhaul
Page
30
Replacement
of
Closing
Springs
Figure
52
shows
the
use
of
a
3
/
4
inch
socket
wrench
to
relieve
spring
tension
on
the
closing
springs
.
The
top
cover
of
the
breaker
has
openings
providing
access
to
the
tension
-
ing
bolts
.
Turning
the
left
and
right
hand
support
bolts
counterclockwise
relieves
spring
tension
.
Once
tension
has
been
relieved
,
retaining
ring
pliers
are
needed
to
remove
the
top
and
bottom
retaining
rings
attaching
each
spring
to
its
cross
-
arm
support
shaft
and
its
crank
arm
.
When
one
or
both
springs
are
reinstalled
,
be
sure
the
support
bolts
are
inserted
inside
their
support
bolt
bushings
.
These
bushings
maintain
the
correct
tension
on
the
closing
springs
.
Replace
all
retaining
rings
during
the
re
-
assembly
.
Re
-
tighten
by
turning
the
support
bolts
clockwise
until
the
support
bolt
bushings
firmly
butt
up
against
the
support
bolt
attachment
bracket
and
the
cross
arm
support
shaft
.
charged
,
all
fasteners
and
connections
are
checked
again
for
tightness
and
condition
before
re
-
installing
the
breaker
into
the
metal
-
clad
switchgear
.
Overhaul
and
Component
Replacement
For
following
procedures
along
with
the
troubleshooting
charts
at
the
end
of
this
section
,
provide
maintenance
personnel
with
a
guide
to
identifying
and
correcting
possible
malfunctions
of
the
GMI
vacuum
circuit
breaker
.
^
WARNING
All
replacement
of
breaker
components
must
be
performed
with
the
breaker
com
-
pletely
de
-
energized
,
the
springs
dis
-
charged
.
Circuit
Breaker
Overhaul
Table
5
lists
the
recommended
overhaul
schedule
for
GMI
circuit
breakers
operating
under
ANSI
usual
conditions
.
When
actual
operating
conditions
are
more
severe
,
over
-
haul
periods
should
occur
more
frequently
.
The
counter
on
the
front
panel
of
the
circuit
breaker
records
the
number
of
operations
.
Table
5
.
Overhaul
Schedule
ANSI
Usual
Conditions
.
Maintenance
Based
Upon
Number
of
Closing
Operations
.
Number
of
Close
Operations
Type
Breaker
Figure
52
.
Use
of
Socket
Wrench
to
Release
Tension
on
Closing
Springs
.
5
-
GMI
-
350
15
-
G
MI
-
1000
5
,
000
Replacement
of
Opening
Spring
The
opening
spring
and
"
nested
”
kickoff
spring
(
when
used
)
may
be
removed
without
a
spring
keeper
or
compres
-
sion
aid
.
The
opening
spring
pull
rod
has
been
provided
sufficient
thread
length
to
allow
the
"
jammed
”
nuts
at
the
top
of
the
assembly
to
be
loosened
and
backed
off
to
relieve
opening
spring
precompression
.
When
used
,
the
kickoff
spring
is
installed
with
no
precom
-
pression
and
may
be
dismounted
by
removing
the
jam
nuts
10
,
000
All
others
Replacement
at
Overhaul
The
following
components
are
replaced
during
an
overhaul
of
the
circuit
breaker
,
when
required
:
Vacuum
interrupters
as
determined
by
contact
erosion
,
or
after
30
,
000
operations
.
Spring
charging
motor
brushes
should
be
replaced
after
10
,
000
operations
.
«
Courtesy of NationalSwitchgear.com