SECTION 7 -Breaker Maintenance (Cont.)
7.3
DRAWOUT MECHANISM POSITION
Maintenance or inspection should be conducted with the
breaker on a workbench. The drawout mechanism must be
placed in the CONN ECT position . This will deactivate the
various i nterlocks which would otherwise prevent the
mechanism or contacts from closing. Engage the racking
handle with the racking shaft and turn clockwise until it
stops.
Remember, before installing the breaker back into its
compartment, the drawout mechanism must be returned to
the DISCONN ECT position.
7.4
SLOW CLOSING THE BREAKER
Closing the breaker slowly, while observing the action of
the mechanism and contacts, is a good way of judging the
correctness of mechanical and contact relationships.
Some of the maintenance procedures described later will
involve operating the breaker in this manner. The proce
dure for slow closing is g iven below.
The c l o s i n g spring m u st be i s o l ated from the
mechanism camshaft. This is done by disconnecting the
lower spri ng assembly from the mating camshaft l inkage.
Remove the hex-head bolt as shown in Fig . 2 1 . Remove
this bolt only with the mechanism in the D ISCHARGED
position and the spring at its minimum extension.
Remove the hex-head bolt only, do not remove or loosen
the slotted head screw shown in Fig. 2 1 . Removal of the
slotted head will cause the closing spring to become dis
engaged from the camshaft with considerable force. Verify
that this screw remains tig htened during the slow close
operation.
After the bolt is removed, use the mai ntenance handle
to rotate the ratchet assembly rol ler onto the closing
prop (see Charging Using The Mai ntenance H and le, sec
tion 5.4). At this point, the closing prop must be removed
by either pushing the CLOSE button on Manual breakers,
or push i ng the closing solenoid armature on electric
breakers (see Fig. 1 3). When the closing prop is removed,
continue turning the camshaft. When the ;contacts and
mechanism are in the fully closed position, the cam will
support the cam rol ler (refer to Fig. 10
&
section 5.3) and
the contacts will develop maximum depression.
Push the TRIP button to release the mechanism and
open the contacts.
CAUTION
- The mechan ism and contacts wi l l open
with normal speed and force.
When replacing the hex-head bolt, turn the camshaft
with the mai ntenance handle to align the mating holes i n
t h e lower spri ng assembly a n d camshaft l i n kage.
FIG. 21 - SLOW CLOSING-LOWER SPRING ASM HARDWARE
20
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