SECTION 6-lnterlocks (Cont.)
6.6
KEY INTERLOCK-STATIONARY
BREAKER
The function of the Key I nterlock 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. 1 9. When
the breaker is in the OPEN position, the end plate assem
bly item #2 on the main shaft pivots the lever item #6
counter-clockwise. This removes the pin item #3 on the
lever from blocking the lock bolt. Extending the lock bolt
rotates the linkage which moves the trip shaft, preventing
the m echanism from closing the breaker.
1 .
Lock
2.
End Plate
3. P i n
4 . Lock Bolt
5.
P i n
6.
Leve r
2
/
·.
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..
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: \
•
I �
I
./ I
' � /
When the breaker is in the CLOSED position, the fly
wheel assembly item #2 is away from the lever item #6.
The lever is spring loaded and rotates clockwise causing
its pin to block the lock bolt extension.
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.
\
\
\
4
5
6
FIG. 1 9 - KEY INTERLOCK-STATIONARY BREAKERS
SECTION 7-Breaker Maintenance
1 8
SAFETY PRECAUTION
WAR NING :
B EFORE INSPEC TING OR BEGIN
NING A N Y MAIN TENA N C E WORK ON THE
BREAKER, IT MUST BE DISCONNECTED FROM
ALL VOL TA G E SOURCES, BOTH POWER A ND
CONTROL, AND THE BREAKER MUST BE IN THE
"OPEN" POSITION.
7.1
LUBRICATION
I n general, the circuit breaker requ i res moderate
l u brication. The m ajority of the factory l ubricated bear
i ng poi nts and s l iding surfaces are accessible for i nspec
tion and if necessary, cleaning and rel u bricating. The on
ly l ubricant used on the breaker for both electrical and
mechanical areas is General Electric specification
D50H D38 (D6A1 5AI Mobilgrease 28 or 32).
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