Westinghouse DBN-1016 Technical Manual page 2

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PREliMINARY DATA
PRELIMINARY DATA
PURPOSE
A circuit breaker has two fundamental pur-
poses: First, to perform normal switching op-
erations
to
isolate a circuit, and second, to
isolate a circuit under fault conditions.
CAUTION - WARNING - THE CIRCUIT BREAKER
SHOULD BE IN THE OPEN POSITION AND THE
SWITCHBOARD DE-ENERGIZED BEFORE IN-
STALLING, ADJUSTING, INSPECTING. REPLAC-
ING PARTS, OR REMOVING THE CIRCUIT
BREAKER. IF THE BUS CANNOT BE DE-EN-
ERGIZED, USE INSULATED HANDLE TOOLS,
RUBBER GLOVES, AND A RUBBER FLOOR
MAT.
INSTALLATION
Tbe
movable component must be removed
before stationary component can be bolted in
switchboard. Normal care in handling the sta-
tionary component is suffiCient.
After securing
the
stationary component the
movable component should be lifted by hooks in
the "lifting holes".
When installing the circuit breaker, care
should be taken to see tbat the supporting sur-
face is even and vertical, and that all leads to
be connected to the circuit breaker are de-en-
ergized. Protect the circuit breaker from dirt
and possible damage.
The connections to
the
circuit breaker studs
should be cleaned, flat and free of burrs to as-
sure full contact area, and firmly clamped or
bolted in place to prevent excessive heating.
The connecting cables should bave adequate cur-
rent carrying capacity. Connecting cables should
be supported so tbat the Circuit breaker studs
Will not be subjected to unnecessary strain.
At no time should the circuit breaker be
allowed to rest upon or be supported by the
current studs. This Will result in unnecessary
damage and stress to the studs and the insu-
lated moldings.
Any discoloration or pitting of the circuit
breaker contacts in evidence when
the
circuit
breaker is received from the manufacturer is
caused by calibrating the breaker and will in
no way interfere with proper functioning of the
circuit breaker.
MAINTENANCE
Periodic inspection
of the
breaker is rec-
ommended. An inspection should always be
made after it is known tbat the breaker bas
opened on a severe short cirCuit. When a cir-
cuit breaker is not operated for long periods
of time, a high resistance oxide or suifide may
form on the contact surfaces which results in
overheating. To burn off this high resistance
film, operate the circuit breaker several times
under normal load at regular inspection periods.
Be sure the breaker is disconnected from
all sources of power before inspecting or re-
pairing.
If excessive heating occurs, look for loose
or corroded contacts or connections.
When inspecting the breaker, examine the
contacts to see if there bas been any severe
pittings or burning of the contact surfaces which
will prevent proper contact Wipe. Rough or
high spots should be removed with a very fine,
clean file or fine, clean sandpaper.
LUBRICATION
In general, the breaker mechanism re-
quires very little lubrication which should be
applied sparingly. Any excessive amount of oil
on
the
breaker parts is apt to collect dust and
dirt and is to be avoided.
The lubrication applied during manufacture
should be sufficient for the life of the breaker.
REPLACNG PARTS
Before replacing any part, the operator
shouid note the position of each part before
remOVing.
When remOving or replacing tension springs
with hooks, the work may be facilitated by pull-
ing On the hooks with a cord or a wire.
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