Siemens GMI Series

Overhaul
Introduction
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
.
Replacement
of
Closing
Springs
-
Figure
38
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
tensioning
bolts
.
Turning
the
left
and
right
hand
support
bolts
counterclockwise
relieves
spring
tension
.
For
early
models
of
the
GMI
breaker
,
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
.
For
later
models
of
the
GMI
breaker
,
the
lower
spring
hangers
are
fastened
to
the
crank
arms
using
hex
socket
shoulder
bolt
and
nut
.
The
nut
is
applied
using
thread
locking
adhesive
,
Loctite
271
,
with
Loctite
type
T
primer
.
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
.
Replacement
of
Opening
Spring
-
The
opening
spring
may
be
removed
and
replaced
without
the
need
to
use
a
spring
keeper
or
compression
aid
.
The
opening
spring
assembly
consists
of
the
top
and
bottom
spring
caps
,
threaded
coupling
rod
with
nuts
,
and
a
support
-
ing
shelf
.
The
shelf
features
location
holes
and
tabs
which
work
in
concert
with
supports
in
the
breaker
frame
to
secure
the
shelf
.
WARNING
h
Hazardous
voltages
and
high
speed
mechanical
parts
.
Can
cause
death
,
severe
personal
injury
,
or
property
damage
.
All
replacement
of
breaker
components
must
be
performed
with
the
breaker
completely
de
-
energized
and
the
springs
discharged
.
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
,
overhaul
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
Closing
Operations
Breaker
Type
5
-
GMI
-
350
15
-
GMI
-
1000
5
,
000
J
All
others
10
,
000
7
Replacement
at
Overhaul
-
The
following
components
are
replaced
during
an
overhaul
of
the
circuit
breaker
,
when
required
:
•
Vacuum
interrupters
as
determined
by
vacuum
integrity
test
,
contact
erosion
,
or
after
30
,
000
operations
.
•
Spring
charging
motor
brushes
should
be
replaced
after
10
,
000
operations
(
reference
kit
18
-
658
-
612
-
886
)
.
|
o
)
0.50
1
4
B
in
:
JuA
JHHli
0.75
u
1
3
*
Figure
39
:
Removal
of
Opening
Spring
.
Figure
38
:
Use
of
Socket
Wrench
to
Release
Tension
on
Closing
Springs
.
27
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