SECTION 6-lnterlocks (Cont.)
FIG. 1 5
RACKING SCREW COVER INTERLOCK
CLOSED POSITION
6.2 POSITIVE INTERLOCK
The function of the positive interlock is to keep the
breaker trip-free while it is being racked in or out between
the CONNECTED and TEST positions.
The positive interlock is located on the breaker's left side
as shown in Fig.
16.
As the breaker moves between the
CONNECTED and TEST positions, the positive interlock
engages with a ramp cam located in the breaker compart
ment. Th1s cam raises the interlock's lever assembly caus
ing the trip shaft to move and preventing the trip latch from
engaging with the secondary latch assembly roller. The
breaker
IS
held trip-free and cannot be closed during this
interval.
6.3 CLOSING SPRING INTERLOCK
The function of the clos1ng sprrng interlock is to dis
charge the clos1ng sprrng as the breaker
IS
being racked
out of 1ts hous1ng Th1s ehm1nates the hazard of a com
pletely charged breaker be1ng discharged after the breaker
is removed from 1ts compartment
The operat1on of the clos1ng sprrng 1nterlock
IS
shown
m
Fig.
17.
The rack1ng mechan1sm arms and the crank are
connected to a common shaft. As the breaker rs racked out
a pin anached to the crank moves through the slot rn the
linkage. The hnkage
IS
connected to a lever wh1ch engages
with a prn on the clos1ng solenoid armature hnkage. When
the rack1ng mechantsm approaches the
DISCONNECT
16
FIG. 1 6 - POSITIVE INTERLOCK
position, the crank's pin reaches the end of the slot in the
linkage. Continued motion of the racking mechanism
causes the linkage to rotate the lever which moves the
closing solenoid armature forward. The armature linkage
then releases the prop, discharging the closing spring.
The Closing Spring interlock should be adjusted to
cause the closing spring to discharge when the racking
mechanism is a minimum of
1
and a maximum of
2Y2
turns short of the fully racked out position. In this position
the racking handle can no longer be turned. If adjustment is
required, use the linkage adjusting screws shown in
Fig.
17.
Note - undue force on the racking handle at the fully
racked out position will cause the lever to move past the
pin on the armature linkage. This will bind u p the overall
interlock. Under these cond itions, continued application
of this force will deform the linkage assembly. A later
lever design (shown in Fig.
17)
includes a stop which pre
vents the lever from moving past the pin. When the pin is
against this stop, undue force may still d eform the link
age assembly.
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