24 S&C Instruction Sheet 761-515
Installation
Checking Operation
Step 27
NOTICE
Open and close the switch slowly ONLY when checking
the operation or making adjustments to the de-energized
switch.
When opening or closing an energized switch, swing the
operating handle vigorously through its full travel without
hesitation.
Arcing and damage to the switch will occur if the ener-
gized switch is operated slowly or left in the partially
Open or Closed position.
Open and close the switch slowly through its full travel.
Check to be sure that the following conditions exist:
(a) With the operating handle as far as it will go in the
closing direction, each switch blade is against its
clos ed stop, a nd eac h swit ch-p ole t ogg le mecha ni sm
lies against its toggle stop as shown in Figure 26
and Figure 4 on page 11. The outboard bearing
crank arm(s) must be in the over-center toggle
position and lie against the stop bolt(s).
(b) In the unlikely event that only one or two switch
poles is fully closed, it is necessary to adjust the
take-up screw(s) on the adjustable pipe coupling(s)
at the switch pole to increase or decrease the
effective length of the interphase operating pipe(s).
See Figure 4 on page11.
(c) The initial factory settings of the outboard bearing
crank-arm length and the stop bolt may require
readjustment to provide the correct amount of
stroke and toggle action. If more stroke is
required, lengthen the outboard bearing crank-
arm (in increments of ⅛-inch) until the blades are
fully home in the Closed position. See Figures 6, 7,
and 8 on page 12. If less stroke is needed, shorten
the outboard crank arm.
(d) It is recommended that the outboard bearing
crank-arm be set to overstroke slightly to provide
positive-drive closure and a denite feel of a locking
action at the operating handle. See the note on the
erection drawing for the amount of toggle to be
obtained.
CAUTION
Be sure to retighten the locknut on the stop bolt and the
clamp bolts on the outboard bearing crank-arm after
adjusting.
(e) When an S&C Switch Operator—Type AS-1A or an
S&C 6801M Automatic Switch Operator is used,
verify that with the switch fully closed there is a
clearance of approximately ⅛-inch between the
outboard bearing crank-arm and its stop bolt. This
clearance is essential to prevent bending of the stop
bolt during power operation. Adjust the stop bolt to
provide this clearance after any other adjustments
made to achieve full closure, stroke, or toggle ac-
tion. Be sure to retighten the locknut when adjust-
ment is completed.
Step 28
Open and close the switch slowly several times and check
the operation of each pole. The following conditions must
be met:
(a) The interrupter must lie in a plane parallel to the
sweep of the blades, and the blades must pass over
the interrupter with approximately equal clearance
on both sides as shown in Figure 26.
(b) As the blade moves in the closing direction,
clearance between the blade opening cam and the
interrupter opening lever must be within the limit
shown in Figure 26.
(c) In the fully Closed position, clearance between
the blade closing cam and the interrupter closing
lever must be within the limit shown in Figure 26.
Also, the clearance between the blade shunt
contact and the interrupter housing must be as
shown in Figure 26.
(d) As the blade moves in the opening direction, the
blade shunt contact must rmly engage the
interrupter housing before the blade disengages
from the jaw contact. (The shunt contact may be
bent as required to conform to these conditions.)
(e) If adjustment is required, loosen the bolts that
fasten the jaw-contact casting to its insulator and
slightly rotate the entire contact-and-interrupter
assembly to achieve the necessary clearances.
Retighten the bolts. Make sure such an adjustment
does not disturb the main contact alignment. The
blade contact spacer must enter the slot in the jaw-
contact casting and be centered in the slot when
the blade is fully closed, and the blade must engage
the stationary contact on-center.
If any of the conditions described in this step cannot be
achieved, contact the nearest S&C Sales Office since it is
likely that damage was sustained during shipping.
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