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GEK-731O,
Power Circuit Breokers
If
the breaker
has an
auxiliary
switch,
external
connections
may be made directly to the
terminaLs
of the switch.
PRE-SERVICE CHECK
Before putting the breaker into service
for
the
first time,
it
would be well to make a cursory ex-
amination and
a preliminary
check of the operation
of the breaker.
This may be
carried
out with
the
breaker
on
a
workbench
or
on
the extended
rails
of
an
equipment
drawout compartment. The
check
should
consist of the following:
1.
Attach
thedrawout racking
handle
to the shaft
onthebreaker afterpushing
thetrip
button and
slid-
ing
the cover
aside.
Turn the handle clockwise un-
til it
stops.
This
will
deactivate the
various
inter-
Iocks which
otherwise would
keep the
breaker from
closing.
NOTE: Remember,
later,
that this
me-
chanism must be
set
back
to
i,ts
original
position before the breaker can be in-
serted
in
the equtpment.
2.
Remove the
arc quencher from
each
pole
and
examine
it for
the
possibility
of broken
or
missiqg
parts.
Do
not
replace the arc quenchers until after
the
preliminary
examination
is
completed.
3.
Charge the
closing
spring.
If
the
breaker is
manually
operated, turn
the
handle
eounterclockwise
as
far
as
it
will
go
(140
degrees), then reverse
the
motion
and
rdturn
it
to the vertical
position. If
the
breaker
is
electrically
operated, use the mainte-
nance handle,
Fig. 5, to turn the
camshaft which
charges the
ciosing spring.
NOTE:
It
probably
nill
be
necessa',ry to
align the triangular socket in
the
handle to
make
it
go on the end
of the shaft.
4.
Close the
breaker.
The
manual
breaker is
closed
by
pushing
the
CLOSE
button in the escutch-
eon.
The
"quick-close" electrical breaker
may
be
closed
by pulling forward
on the armature
of
the
closing solenoid which
is
located
beneath
the
me-
chanism
and may
bereached
throughthe large rec-
tangular
opening
in thelower
end
of the
escutcheon.
This maybe
done
safelysince
none
of the parts that
move
in closing are in this
area.
(See
Fig.
64,.)
Observe the difference between the position of
the
stationary
contacts when the
breaker
is
opened
and when
it is
closed. The main
contacts
should
8
move
in
("wipe") at least 1/16
inch.
If
they
do
not
seem
to
do
so,
and
careful measurement confirms
this, refer to
the section
of
these
instructions en-
tiiled
"CONTACT MAINTENANCE.
"
5.
Make
swe
that
a-ll
the
devices used
for trip-
ping
the breaker
open
Erre
operable. Manually
ac-
tivate
thesewith thebreaker closedto establish this.
Devices
in this
category
are the
manual
trip,
the
overload devices,
the
shunt
trip,
and
the
under-
voltage device.
6.
If
the
breaker
is
a
drawout breaker,
check
the
operation
of
the
interlock devices.
Make sure
that
Iifting interlock pin
(3),
Fig. 4,
will trip
the
breaker and that the
sliding
cover (1),
Fig.
8 can-
not
be opened
if
the breaker
is closed.
Check
that
the closing spring
wiII
discharge
automatically
if it
is
charged,
and
the
drawout
racking
handle
is
cralked
as
far
as
itwill
go
inthe
counterclockwise
direction.
7.
Replace the
arc
quenchers, clamping them
securely.
8.
The
electrical
operation
of
electricai break-
ers
should
be checked when
control power
is avail-
able, with the breaker
in
the
"test"
position
in
the
drawout equipment compartment.
OPERATING
THE BREAKER
A breaker may be
equipped
to
operate either
manually
or electrically.
Both types
of
operation
result in
the
same
fast-closing
movement
as far
as
the contact action
is
concerned.
The
variation
is in
the rpay
energy
is
stored in theclosing spring,
and how i.t
is
released.
'NANUAt
CLOSING
Manually operated AI(R
breakers are constructed
with
front-mounted
handles.
Handle
operation
re-
sets the mechanism
and
fully
charges the closing
spring.
A
complete charge
is
accomplished in
either cranking the
handle
through
one
cycle
(135-
degree swing)
or
three cycles
(50-degree swing).
The
CLOSE
button, mounted
on
the escutcheon,
is
used
to close
the breaker contacts and the TRIP
button
to
open
them.
If
equipped
with
a closing solenoid, a
manual
breaker may beclosed remotelyby a control switch
or
relay.
Before
this
can be done, however,
the
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