I
INTRODUCTION
-
Continued
I
hesitation under %-inch ice formation; close interphase
simultaneity; long life of fault-closing contacts under
normal operating duties; and avoidance of excessive
switching transients due to prolonged or unstable
prestrike arcing. Mark
V
Circuit-Switchers
are
provided
with high-speed, high-torque power operation by means
of S&C Switch Operators--Type CS-1A.
High-speed tripping of power-operated Mark
V
Circuit-Switchers
is
furnished by the S&C Shunt-Trip
Device. This optional accessory (Circuit-Switcher
Catalog Number Suffix “-T1” or “-T2”) provides high-
speed (8-cycle) circuit interruption. The S&C Switch
Operator-Type CS-1A is required
if
the shunt-trip
device is specified.
Basis
of
Fault-Closing Ratings
The two-time duty-cycle fault-closing rating
set
forth
above applies to Integer Style Mark
V
Circuit-Switchers
when powered by S&C Switch Operators--Type CS-lA,
and is based on performance
as
follows:
The Circuit-Switcher is capable of two fault-closing
operations consisting of closing against and carrying
for three seconds its rated fault-closing current, after
which it can carry and interrupt its rated continuous
current and
is
capable of power operation-either
opening or closing.
After each occasion consisting of either one or two
fault-closing operations
at
its rated fault-closing
current, the Circuit-Switcher must be inspected and
any necessary repair or replacement
of
the fault-
closing contacts made to restore the device to its
original condition.
Manual Operation
S&C Mark
V
Integer Style Circuit-Switchers may be
manually operated by means of an S&C Manual Geared
Operating Handle. Manually operated Circuit-
Switchers, however, do not provide the performance
features obtainable with power-operated Circuit-
Switchers as described under “Power Operation,” such
as
fault-closing ratings and opening and closing under
ice formation-nor can they be furnished with the
shunt-trip device.
Also,
for manually operated Mark
V
Circuit-Switchers, the degree of simultaneity of opening
and closing
of
the three pole-units depends on the
proper installation and adjustment of the operating
mechanism-as well
as
on the speed
of
cranking
at
the operating handle-and must be considered in
establishing ground-relay settings.
Mounting
of
Circuit-Switchers
The high operating speed which makes possible many
of the Mark
V
Circuit-Switcher’s superior performance
features when power operated brings about high
acceleration and deceleration rates, resulting in high
dynamic forces-for which S&C Mounting Pedestals
were specifically designed, and are thus highly
recommended. Alternately, Circuit-Switchers can be
installed on the user’s steel pedestals or supporting
structures-which must meet specific static and
dynamic deflection limits shown in S&C data sheets,
so
that the dynamic forces will be absorbed by the
pedestals and not transferred to adjoining bus or other
apparatus (e.g., bushings).
Use
of flexible-conductor connections
at
Circuit-
Switcher’s terminal pads will compensate for inherent
INSTRUCTION
SHEET
7
1
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S&C ELECTRIC COMPANY Chicago Page
3
of
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S&C ELECTRIC CANADA LTD.
Toronto
December 16,1991
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