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4 7
after disconnecting the shunt
connection
.
Figure
20
shows the method
of lifting
the
13.8
KV
arc
chute with the accessory
arc
chute
lifter
.
DH
-
P line is
about the
same as
the
West
-
inghouse Type DH suffix E line for
a
given
set
of conditions
.
With experience
,
each
user can set an
inspection and maintenance
schedule which is
most
economical for the
particular
case
.
With the maintenance
closing
handle
,
close the breaker
contacts
slowly
.
The
movable
arcing
contact
and
two
main
contacts
should
enter
the stationary fingers
centrally
between
pairs
of fingers
.
Move
-
ment
outward of the
stationary
fingers
on
each side
of
the movable member
as
the
movable
contact
enters
should be
about
equal
.
Complete the closing
of the
breaker
until it is latched closed
.
These breakers
are
adjusted
,
inspected
and tested
at
the factory in line with high
standards
of quality control and reliability
.
They should
not
require readjustments
before
placing in service
.
Do
not
change
any
adjustments
,
assemblies
or
parts
unless
there has been
an
obvious damage
or
in
-
correct
adjustment
.
However
,
handling and
transportation
conditions could
cause
loss
of
adjustment
or
damage
.
In this overall
operation
refer
to
Fig
.
21 for
required
deflections
,
overlap
and tolerances in the
contact system
.
Therefore
,
some
inspection
should be
done
on the breaker
immediately
after
unpacking
.
The
4.16
KV breaker is packed
all in
one crate
,
cartons ,
and the main barrier assembly
are
inside
the
crate
with the breaker
.
Adjustment
for
contact
overlap
is by
change in
the effective length of the lift
rod
.
fective length of lift rod
by adjusting
the
nuts at
the
top
end of the rod
.
To decrease
overlap
,
decrease effective length of lift
rod
.
The
arc
chutes
,
in 3
To increase overlap
,
increase ef
-
The
13.8
KV breakers
are
packed in
3
crates
, the
basic breaker unit in
one
crate ,
3
arc
chutes in
one crate
and the
barrier assembly in another
crate
.
On the
rare
possibility that
some
of the
main stationary fingers may be slightly
out
of alignment with the movable
number
beyond the tolerances in Fig
.
21
,
they
may
be
set
by
careful
blows with
a
soft
mallet
.
These packing methods permit easy
inspection
before final
assembly
of
arc
chutes
and barriers
on
the breakers
.
CONTACTS SETTINGS
NOTE
:
Slight misalignment of the arcing
con
-
tacts may
be remedied in
a
similar
manner
.
If there is much misalignment
or
damage
to
any of the
contacts ,
they
should be
replaced
.
On breakers with
stored
energy
mechanisms
,
be
-
fore
trying
to
close the breaker with the
mainte -
nance
closing
handle
,
make
sure
that the closing
spring is
discharged . It
can
not
be closed this
way
with the
spring
charged
.
If
it is
tried
,
the
tripping
linkage
may
be damaged . Breaker should
be
open
and
spring
discharged
as it is
unpacked
.
The movable
contact
is
hinged
to
the
lower
contact
block by
a
stud and
spring
washers
.
against the block and it should
not
be pos
-
sible
to
rattle
the
blades
against
the block
by sidewise hand effort
.
The blades should fit snugly
Figure lb shows a 4
,
16 KV breaker
arc
chute tilted back for getting
to
the
contacts
.
This is done directly
by hand
,
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