7 .1 2.2 F AND G SWITCH ADJUSTMENT
For proper electrical operation, the F and
G
mechani
cally operated switches must operate at the proper point in
the closing cycle. If these switches are to be replaced,
measure the distance between the tip of the switch button
and the bracket on which they are mounted. When the new
switch is mounted, duplicate the measured dimension,
then check for proper operation.
When a normal closing operation occurs, the ratchet
usually comes to a stop with an arbitrarily designated
ratchet tooth No.
1 ,
Fig. 37, engaged by the holding pawl.
This tooth is the one which is In line with an I maginary
line passing through the centers of the camshaft (2) and
the rivet opposite the roller on the ratchet assem bly. It Is
matter of no concern If the action stops on a different
tooth, but it is i m portant to positively identify tooth No.
1
by the method described.
To check the switch action, after tooth No.
1
has been
identified, turn the camshaft with the maintenance handle
and count the teeth as they pass the holding pawl. By using
a continuity tester, observe when the switches operate as
the ratchet turns. The normally open F switch on the left will
close, and the
G
switch will open.
Electrical breakers should operate the switches while
moving from tooth No.
1 0
to tooth No.
1 1 .
If this check shows that an adjustment is needed, the
switch to be corrected can be moved closer to or farther
away from the paddle which operates the switches.
A
very
thin open-end 5/8-inch wrench will be needed to loosen or
tighten the nuts which fasten the switches to the bracket.
7.1 3 DRAWOUT
MECHANISM
The drawout mechanism shown in Fig. 38 moves the
breaker through the DISCONNECTED, TEST, and CON
NECTED positions. Fig. 39 shows how the d rawout
mechanism
is mounted to the breaker.
As the ra
ck
i
ng handle is turned, the internally threaded
trunn1on moves on the screw threads, rotating the hex
shaft. on the ends of which are fastened the arms which
engage the f 1xed pins in the draw
o
ut
e
ncl
os
u
r
e
.
The
trunn1on travels between the two jamb nuts on the
end
of
t he
screw. and the adjustment sleeve, which stops
th
e trunn1on
movement at the other extreme point of
its
travel The trunnion
i
s
against the jamb nuts when the
breaker 1s fully racked
out
and
against the sleeve when
fu
ll
y racked m .
The rackmg mechanism
i s adjusted at the factory as
sembly operat1on so
that the action is stopped in either
d1rect1on at t he prec1sely
correct point. The jamb nuts are
set so
that w hen
the trunn1on is against them the relation
between the arms
and the equipment pins they engage is
shown
m
F1g
38
The length of the sleeve, which is free to
slide
on the threaded shaft ,
IS
controlled by the amount of
thread
engagement
between the sleeve and its collar. This
lengt h 1s adJ usted
to stop the trunn1on when the distance
between the ends
of
the equipment
and breaker studs is
.032"
to
.2 1 8
. . .
After th1s
adJustment is made, the sleeve
and 1ts collar are locked together
by the set screw.
1 TOOTH
FIG. 37 - LOCATION OF RATCHET TOOTH
N0. 1
29
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