'
SECTION 6-lnterlocks
AKA
breakers are equipped
with
safety interlock devices
that are required by Industry Standards and Certifying Au
thorities. Interlock devices for special applications are also
available as options. The standard interlock devices de
scribed below are used only on drawout breakers. Station
ary breakers have no required interlocks.
6.1 RACKING MECHANISM INTERLOCK
The function of the racking mechanism interlock is
to
prevent
the breaker from moving from its
CONNECTED
position before it is in the OPEN position.
The racking mechanism drive
shaft is located behind the
RACKING SCREW
cover
shown in Fig.
14.
This cover
must be slid to the right to gain access to the drive shaft.
When the breaker is in the CLOSED position,
a
link en
gages the RACKING SCREW cover preventing it from
being opened. This link
is driven by the motion
of the
OPEN/CLOSED indicator as shown in Fig.
15.
The TRIP button also engages with the RACKING
SCREW cover in both the OPEN and CLOSED positions.
Therefore, the TRIP button must be pushed in before the
cover can be opened. This will open the breaker if it was
closed and also remove the OPEN/CLOSED linkage dis
cussed above.
When the RACKING SCREW
c
o
ve
r
is open
it holds the
TRIP button in. This keeps the breaker t
r
i
p
-
fr
e
e
so a
mechanism closing cycle will not cause contact movement
especially when the breaker is being racked in or out.
FIG. 1 4-A - RACKING SCREW
FIG.
14-B
15
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