ABB 15VHK500 - Circuit Breaker Operation

AM
IB
6.2
.
7.7
.
-
1
Page
7
ASEA
BROWN
BOVERI
d
.
The
measurement
with
the breaker
open
should
be
at
least
.
020
"
greater
than
when
the
breaker is closed
.
e
.
When
contact
wipe
is
less
than
the
.
020
and
it
has
been determined that the breaker
closes
fully
and
there
is
not
a
mechanical
problem
,
then
the
interrupter
should
be
replaced
due
to contact
erosion
.
4
.
Contact
Air
Gap
(
See
Fig
.
5
)
The
contact
air
gap
is
set at
the
factory
at
the nominal dimension
of
.
43
.
This value
will
normally
increase
as
the
contacts
erode
.
A
check
of
the
contact
air
gap
checks
that the breaker does
open
fully
and
that the
gap
is
sufficient
to
withstand
the
applied
voltage
.
The
measurement
is made
as
follows
for
the three
poles
.
a
.
Open
the
breaker
and
discharge
the
closing springs
.
b
.
Measure
and
record dim
.
Y
2
.
c
.
Close
the
breaker
,
measure
and record
dim
.
Y
.
d
.
The
air
gap
is the
difference
between
the
two
meas
-
urements
.
The
acceptable
limits
are
.
40
—
.
54
,
with
the
upper
limit
being
approached
as
contact
wipe
approaches
the minimum
.
On
circuit breakers
with
normal
or
less than normal load
-
ings
,
the listed values
may
be
exceeded
up
to
150
%
.
For
optimum
performance
of
the
circuit
breakers
during
periods
of
increased
loading
,
it
is
recommended that
the
listed values
not
be
exceeded
.
Insulation
Cleaning
Any
dirt
,
dust
or
grease
should
be
removed
from
the
surfaces of
the
entire
current
carrying
structure
,
vacuum
interrupter
,
base
insulation sheet and
interphase
barrier
assembly
.
Wiping
the
surface
with
an
oil
-
free
solvent
on a
clean
cloth
or
industrial
wiper
is
normally
sufficient
for
this
purpose
.
‘
Remember
to
discharge
mid
-
band
ring
on
interrupters
so
equipped
.
CIRCUIT
BREAKER
OPERATION
AND
CONTACTS
1
.
To
check
breaker
operation
,
the breaker
should
be
withdrawn
from
the switchboard
,
the
front
cover
and barrier
removed
and
the
racking
screw
turned
two
to
three
turns
clockwise
until
the
racking unlocking
lever
snaps
into
the
first
position
corresponding
to
the
disconnect
position
.
2
.
Fully
closed
breaker
(
See
Fig
.
3
)
.
Charge
the
closing
springs
and
turn
the
motor
switch
(
1
)
off
.
Close
the breaker
.
Engage
manual
charge
handle
(
3
)
with
charging
lever
(
3
)
.
During
the
initial
portion
of
the
downward
stroke
of
the
handle check
to
see
which direction
the
closing spring
guides
(
2
)
move
.
If
the
spring
guides
start
to
move
out
then
the
breaker
did
fully
close
. If
the
spring
guide begins
to
move
in
and
with
additional
pumping
moves
in
until
the
mechanism
can
be
heard
to
“
snap
in
”
,
then the breaker did
not
fully
close
originally
.
Excess
contact
pressure
orfriction
can cause
this condition and
if
it
cannot
be relieved then
the
factory
should
be
consulted
.
3
.
Contact
wipe
(
contact
pressure
)
(
See
Fig
.
5
)
.
The
contact
air
gap
and
contact
wipe
is
set
at
the
factory
by
setting
the
vertical
position
of
the
interrupter
(
1
)
and
the
vertical
position
of
the
pushrod
(
2
)
.
These
parts
should
not
be
repositioned
in
the
field
unless
a
pushrod
change
is
required
to
correct contact
sequence
as
described
else
-
where
.
Contact
wipe
is
set at
the
factor
at
.
11
minimum
.
Contact
erosion and
wear
in
mechanical
parts
will
cause a
reduction
in
contact
wipe
over
the
life of
the breaker and
a
check should
be
made
to
insure
that
the
wipe
is
not
less
than
.
020
"
.
The
measurement
is
made
as
follows
for
the
three
poles
:
a
.
Open
the breaker and
discharge
the
closing springs
.
b
.
Using
a
thin
6
"
scale
measure
from
the
spring
base
to
pivot pin
3
.
Record
dimension
X
2
.
c
.
Close
the breaker and
again
measure
between the
spring
base and
pivot
pin
3
.
Record
Dim
.
X
.
5
.
Contact
sequence
(
See
Fig
.
5
)
.
All
three
poles
should
touch
within
2
millisecond
at
normal
closing
speeds
.
An
oscilloscope
,
oscillograph
or
other
timing
method
may
be
used
to
establish the
2
millisecond
timing
.
Before
checking
contact
sequence
,
check that
the
contact
wipe
and
air
gaps
are
correct
.
It
is
not
expected
that the
contact
sequence
should
exceed
the
2
millisecond
limit
;
therefore
,
before
attempting
to
readjust
,
check
that the
test
equipment
and
procedure
are
correct
.
Also consider
,
espe
-
cially
when
testing
with
electronic
equipment
,
that
.
002
seconds
vacuum
interrupter
contact
bounce is
permissible
during
normal
closing
and this bounce
can
influence
the
contact
touch
measurements
.
If
it
is determined that the
contact
sequence
is
not
within
the
2
milliseconds
,
then
adjustment
is
required
.
Usually
,
read
-
justment
of
one
pole
should
be
sufficient
so
that
all
three
poles
touch
within
2
milliseconds
.
The
air
gap
of
the
pole
to
be
changed
should be decreased
if
the
contacts
of
that
pole
are
touching
afler
the other
two
poles
,
or
increased
if
the
contacts
are
touching
before
fhe
other
two
poles
.
The air
gap
is decreased
by
turning
pushrod
(
2
)
clockwise
,
viewing
from
the
top
of
the
breaker
,
and increased
by
turning
counterclockwise
.
Before
the
pushrod
can
be turned
,
the
breaker
must
be
open
,
closing springs discharged
and
pin
(
3
)
removed
.
With
the breaker
open
,
the
vacuum
in
the
interrupter
maintains
a
constant
upward
force of
approx
.
25
lbs
.
on
the
moving
contact
and
pushrod
(
2
)
.
Therefore
,
before
remov
-
ing
pin
(
3
)
,
the
contact must
be held down
in
the
open
position
by
temporary
spacers
at
location
(
z
)
.
After
remov
-
ing retaining ring
(
4
)
and
pin
(
3
)
,
rotate
pushrod
(
2
)
as
Courtesy of NationalSwitchgear.com