SECTION &-Interlocks (Cont.)
6.6
KEY INTERLOCK-STATIONARY
B REAKER
The function of the Key Interlock is to prevent an open
breaker from being closed when the lock bolt is extended
and its key is removed.
The operation
of
this interlock is shown in Fig.
19.
When
the breaker is in the OPEN position, the end plate assembly
on the main shaft pivots the lever counter-clockwise. This
removes the pin on the lever from blocking the lock bolt.
Extending the lock bolt rotates the linkage which moves the
trip shaft, preventing the mechanism from closing the
breaker.
1.
Lock
2.
End Plate
3.
Pin
4.
Lock Bolt
5.
Pin
6.
Lever
6.7
OPTIONAL INTERLOCKS
The optional interlocks are key interlocks and door inter
locks. On drawout breakers, these devices are mounted in
the equipment and are part of the breaker enclosure. Pad
locks may be used to lock the "inner" house in the "discon
nected" position.
When the breaker is in the CLOSED position, the
flywheel assembly is away from the lever. The lever is
spring loaded and rotates clockwise causing its pin to block
the lock bolt extension.
5
6
FIG. 1 9 - KEY INTERLOCK-STATIONARY BREAKERS
SECTION 7-Breaker Maintenance
18
SAFETY PRECAUTION
WARNING:
BEFORE INSPECTING OR BEGIN
NING ANY MAINTENA NCE WOR K ON THE
BREAKER, IT MUST BE DISCONNECTED FROM
ALL VOL T AGE SOURCES, BOTH POWER AND
CONTROL. AND THE BREAKER MUST BE IN THE
"OPEN" POSITION.
7.1
LUBRICATION
In general, the circuit breaker requires moderate
lubrication. The majority of the factory lubricated bear
ing points and sliding surfaces are accessible for inspec
tion and if necessary, cleaning and relubricating. The on
ly lubricant used on the breaker for both electrical and
mechanical areas is General Electric specification
D50HD38 (Mobilgrease 28).
'
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