SECTION 7-Breaker Maintenance (Cont.)
7.3 DRAWOUT MECHANISM POSITION
Maintenance or inspection should be cond ucted with the
breaker on a workbench. The d rawout mechanism must be
placed i n 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 DISCONNECT 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 given below.
The c l o s i n g spring m ust be i s o l ated fro m the
mechanism camshaft. This is done by disconnecting the
lower spring assembly from the mating camshaft linkage.
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 m inimum 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 tightened during the slow close
operation.
After the bolt is removed, use the maintenance handle
to rotate the ratchet assembly rol ler onto the closing
p rop (see Chargi ng Usin g The Maintenance Handle, sec
tion 5.4). At t h i s point, the c l osing prop m ust be removed
by either pushing the CLOSE button on Manual breakers,
or pushing the closing solenoid armatu re on electric
breakers (see Fig. 1 3). When the closing p rop is removed,
contin ue turn i ng 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 w i l l develop max i m um depression.
Push the TRI P button to release the mechanism and
open the contacts.
CAUTION
-
The mechan ism and contacts w i l l o pen
with normal speed and force.
When replacing the hex-head bolt, t u rn the camshaft
with the maintenance handle to align the mating holes i n
the lower spring assembly a n d camshaft l i n kage.
FIG. 21 - SLOW CLOSING-LOWER SPR ING ASM HARDWARE
20
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