Checking The Optional Shunt-Trip Device - S&C Mark V Circuit-Switchers Installation Manual

Installation
STEP 3� Check for simultaneous closing of the three pole-
units by visually determining engagement of the
fault-closing contacts. Check each pole-unit for
proper blade penetration and readjust if neces-
sary, as described in Step 4 on page 22.
STEP 4� While it is not critical, the normal blade opening
is 90 degrees. It may be desirable from an appear-
ance standpoint, for all three pole-unit blades to
achieve an equal stance when in the fully Open
position. If adjustment is required. Loosen the
ball-joint shaft locking nut. Turn the shaft (which
is an eccentric) to achieve a satisfactory blade
position. See Figure 10 on page 16. Retighten the
locking nut. Note that it is not necessary to loosen
the socket-head screw (in the blade crank-arm)
to make this adjustment. It is not a lock screw.
Repositioning the ball-joint shaft will affect
the depth of blade penetration into the jaw
contact during completion of the closing stroke.
The difference in penetration will range from
very slight (at lower voltage ratings) to significant
(at higher voltage ratings).
When the adjustment described above is
performed, recheck for proper blade penetra-
tion and readjust if necessary (as in Step 4 on
page 22).
STEP 5� After satisfactory group operation has been
attained manually, adjust the switch operator
for electrical operation as described in the
"Adjusting the Switch Operator" section of S&C
Instruction Sheet 719-500.
Operate the circuit-switcher several times with
STEP 6�
the switch operator and observe the action.
Operation should appear smooth, in both the
opening and closing direction, with the drive-
shaft crank of each pole-unit coming to rest in
a positive-toggle position.

Checking the Optional Shunt-Trip Device

When the optional shunt-trip device is specified, the control
wiring for the shunt-trip solenoids should be connected
to the terminal block in the switch operator at this time.
See S&C Instruction Sheet 711-600.
STEP 1� Opening of the three pole-unit interrupters by the
switch operator should be simultaneous within
1.0 cycle (0.016 second).
26 S&C Instruction Sheet 711-510
(a) Check for simultaneity by slowly opening
the circuit-switcher (by manually cranking
the switch operator). Listen for the tripping
action of the individual interrupters, and
observe the interrupter targets.
(b) Note the point at which the first interrupter
trips. From this point, no more than 40
degrees of rotation of the manual operating
handle should be required before the other
two interrupters trip. When this condition
exists, the desired simultaneity has been
attained.
STEP 2� If simultaneity within the limits specified in Step 1
is not attained, recheck the blade crank-arm at
the top of each brain with the circuit-switcher
in the fully Open position. (See Figure 15 on
page 20.) If any blade crank-arm fails to meet
its open stop, it will be necessary to isolate the
pole-unit(s) affected by loosening the clamps
at both ends of the applicable interphase and/
or connecting shafts. Then proceed as follows:
(a) At the applicable pole-unit(s), loosen the
four bolts fastening the brain to the rotating
insulator, and install the ½–13 X 2 ¾-inch
positioning bolt, flat washer, and nut as
shown in Figure 5 on page 12. Tighten the
nut securely so the two mating surfaces of
the tabs are drawn together as shown in
Figure 6 on page 12.
(b) Securely tighten the four bolts fastening the
brain(s) to the rotating insulator.
(c) At each end of the previously loosened inter-
phase and/or connecting shafts make certain
the piercing set screws do not protrude
through the body of any coupling. Rotate
the shafts about 90 degrees (to provide a
fresh piercing surface). At each coupling
tighten the clamp bolts equally so the clamp
pulls down evenly. Then, tighten the asso-
ciated piercing set screws, piercing the
shaft, and continue turning until a firm
resistance is felt.
(d) Remove the positioning bolt(s) installed in
Step 2(a).
In the event the blade crank-arms are correctly adjusted
and the specified simultaneity cannot be attained, contact
your local S&C Sales Office.