Siemens GMI Series

Maintenance
Damper
Assembly
Check
-
GMI
circuit
breakers
contain
a
viscous
damper
assembly
,
shown
in
Figure
37
,
and
described
in
some
detail
on
page
14
,
and
in
Figure
19
.
While
performing
the
manual
spring
charging
check
,
a
simple
check
of
the
damper
mounting
yoke
,
pin
,
retaining
rings
,
and
the
nut
for
tightness
should
be
completed
The
cylindrical
surface
of
the
damper
and
telescoping
tube
should
be
well
greased
.
The
full
periphery
of
the
tube
and
cylinder
should
be
coated
with
Beacon
325
.
of
acceptable
contact
condition
is
checked
by
the
visibility
of
the
white
erosion
mark
shown
in
Figure
36
.
The
white
erosion
mark
is
located
in
the
keyway
(
or
slot
)
on
the
movable
stem
of
the
vacuum
interrupter
,
near
the
plastic
guide
bushing
.
The
contact
erosion
check
procedure
is
:
•
Be
sure
the
breaker
primary
contacts
are
Closed
.
•
Observe
the
white
erosion
mark
(
Figure
36
)
of
each
pole
.
When
this
mark
is
visible
,
contact
wear
is
within
acceptable
limits
.
For
some
circuit
breakers
(
with
a
vacuum
interrupter
having
an
internal
arc
shield
)
,
a
flashlight
and
dental
mirror
will
be
needed
to
observe
the
white
erosion
mark
Electrical
Control
Checks
The
electrical
controls
of
the
GMI
circuit
breaker
should
be
checked
during
inspections
to
verify
absence
of
any
mechani
-
cal
damage
,
and
proper
operation
of
the
automatic
spring
charging
and
Close
and
Trip
circuits
.
Unless
otherwise
noted
,
all
of
these
tests
are
performed
without
any
control
power
applied
to
the
circuit
breaker
.
WARNING
Tripping
spring
is
charged
.
If
trip
latch
is
moved
,
high
-
speed
movement
of
components
can
cause
serious
injury
.
Observe
precautions
concerning
physical
contacl
with
components
of
the
circuit
breaker
subjected
to
sudden
,
h
gh
speed
movement
.
Check
of
the
Wiring
and
Terminals
-
1
Physically
check
all
of
the
breaker
wiring
for
evidence
of
abrasion
,
cuts
,
burning
or
mechanical
damage
.
2
.
Check
all
terminals
to
be
certain
they
are
solidly
attached
to
their
respective
device
.
Check
of
the
Secondary
Disconnect
-
In
addition
to
checking
the
terminals
of
the
secondary
disconnect
,
the
secondary
contact
fingers
need
to
be
free
to
move
without
binding
Depress
each
finger
,
confirm
presence
of
spring
force
(
con
-
tact
pressure
)
,
and
verify
freedom
of
motion
.
4
.
Press
the
red
Trip
pushbutton
after
completing
the
contact
erosion
check
.
Visually
verify
the
Discharge
condition
of
the
closing
springs
and
that
the
circuit
breaker
contacts
are
Open
.
5
.
Press
the
black
Close
pushbutton
.
Nothing
should
happen
.
The
manual
spring
check
should
demonstrate
smooth
op
-
eration
of
the
operating
mechanism
.
AWARNING
h
Hazardous
voltages
and
high
-
speed
mechanical
parts
.
Will
cause
death
,
severe
personal
injury
,
or
property
damage
.
Read
instruction
manuals
,
observe
safety
instructions
and
limit
use
to
qualified
personnel
Automatic
Spring
Charging
Check
—
Control
Power
Re
-
quired
-
Repeat
the
automatic
spring
charging
check
de
-
scribed
in
the
section
entitled
Installation
Checks
and
Initial
Functional
Tests
.
Primary
tasks
of
this
check
are
:
1
.
The
breaker
is
energized
with
control
power
*
or
this
check
.
2
.
De
-
energize
the
source
of
control
power
(
Figure
1
)
.
3
.
Install
the
breaker
end
of
the
split
plug
jumper
over
the
secondary
disconnect
of
the
circuit
breaker
.
The
split
plug
jumper
has
one
male
and
one
female
connector
and
cannot
be
installed
incorrectly
(
Figure
7
)
.
4
.
Install
the
switchgear
end
of
the
plug
jumper
over
the
second
-
ary
disconnect
block
inside
the
switchgear
(
Figure
8
)
.
5
.
Energize
the
control
power
source
.
6
.
When
control
power
is
connected
to
the
circuit
breaker
,
the
clos
ng
springs
should
automatically
charge
.
Visually
verify
that
the
closing
springs
are
charged
.
Figure
37
:
Damper
Assembly
.
24
Courtesy of NationalSwitchgear.com