Siemens 5-GMI-350 - High-Potential Tests; Vacuum Integrity Check; As-Found Insulation and Contact Resistance Tests

Maintenance
&
Overhaul
Page
22
t
Figure
40
shows the
breaker
spring
condition
indicator
in
the
Discharged
position
.
5
.
Remove the
breaker
from
the
switchgear
.
Refer
to
the
preceding
installation
section
of
this
manual
for
special
instructions
and
precautions
regarding
removal
of
the
upper
breaker
.
6
.
The breaker
can
be located either
on
the
floor
or an
insulating
pallet
.
Each breaker
has
four
wheels
and
handles
to
allow
one
person
to
maneuver
the
unit
on a
level
surface
without
assistance
.
Checks of
the
Primary
Power
Path
The
primary
power
path
consists
of
the
three
vacuum
inter
-
rupters
,
the three
upper
and
the
three lower
primary
discon
-
nects
.
These
components
are
checked
for
cleanliness
and
condition
.
The
vacuum
interrupters
are
also
checked
for
vacuum
integrity
.
Some
test
engineers
prefer
to
perform
the
contact
erosion
check
during
the
manual
spring
charging
check
of
the
operator
,
since
charging
of
the
springs
is
necessary
to
place
the
contacts
in
the
closed
position
.
Also
,
the
vacuum
integrity
check is
usually
performed
in
conjunction
with
the
High
Potential
tests
.
These
instructions
follow
the
recommendation
that
these
tests
(
contact
erosion
/
manual
spring
charging
check
,
and
vacuum
integrity
/
high
potential
tests
)
will
be
combined
as
described
.
Cleanliness Check
Figure
41
is
a
side view
of
the
GMI
circuit
breaker
with
one
of
the
side
insulating
panels
removed
tor
show the
vacuum
interrupter
,
and the
upper
and lower
primary
disconnects
.
All
of
these
components
must
be
cleaned and
free
of
dirt
or
any
foreign
objects
.
Use
a
dry
lint
-
free
cloth
.
Inspection
of
Primary
Disconnects
Figures
42
and
43
show
the
primary
disconnect
contact
fingers
both
in
the
engaged
(
Figure
42
)
,
and
the
disen
-
gaged
positions
(
Figure
43
)
.
When
the
contacts
are
mated
with
the
switchgear
’
s
primary
stud
assembly
,
there is
force
-
ful
contact
distributed
over
a
wide
area
.
This
maintains low
current
flow
per
individual
contact
finger
.
I
Figure
39
.
Outer
Door
of
Switchgear
Cubicle
Open
for
Access
to
Breaker
Controls
.
4
.
Perform
the
spring discharge
check
.
This
is done
by
first
depressing
the
red
Trip
pushbutton
.
Second
,
depress
the
green
Close
pushbutton
.
Third
,
depress
the red
Trip
pushbutton
again
,
and observe
the
spring
condition
indicator
.
It
should read
“
Discharged
.
”
4
Figure
40
.
Tripping
Breaker
to
be
Inspected
.
Courtesy of NationalSwitchgear.com