Westinghouse RC, Instructions Manual

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Westinghouse
I.L. 41-661C
INSTALLATION
•
OPERATION
•
MAINTENANCE
I N S T R U C TI O N S
TYPE RC AUTOMATIC RECLOSING RELAY
C AUT I O N
Before putting relays into service, remove
all blocking which may have been inserted for the
purpose of securing the parts during shipment, make
sure that all moving parts operate freely, inspect the
contacts to see that they are clean and close prop­
erly, and operate the relay to check the settings and
electrical connections.
APPLICATION
The type RC automatic reclosing relay is used
for automatic reclosure of AC or DC electrically oper­
ated circuit breakers after they have been opened by
overcurrent or other protective relay action. The relay
may be adjusted to provide several reclosures at pre­
determined time intervals, so that in case the breaker
does not remain closed after the first reclosure addi­
tional reclosures will be made. The first reclosure
usually is an instantaneous reclosure through pre­
closed contacts since system operating experience
has shown that the majority of faults are of a tem­
porary nature, such as lightning flashovers, and will
not be re-established after interruption of the fault
current. Consequently, service interruption can be
minimized by the use of an instantaneous reclosure.
However, the first reclosure may be delayed if desired.
In case the circuit breaker does not remain closed
after the first reclosure, the relay will make additional
reclosures at suitably graded intervals. It is common
practice to make two additional reclosures, but the
relay may be adjusted to make any number up to a
total of six reclosures if desired. If the breaker does
not remain closed after the final reclosure, the timing
drum stops in the "Lockout" position, and any further
attempts at reclosure must be made by manual opera­
tion of the control switch. However, if the breaker
remains closed after any automatic reclosure, or, sub­
sequently, after manual reclosure, the relay timing
drum will advance to and stop at the "Start" position,
where the relay is in readiness for another cycle of
automatic reclosures following the next tripping of
the breaker.
For any automatic reclosing application, the de­
rating factors for breaker interrupting ability should
SUPERSEDES I. L.
41-661
B
*Denotes change from superseded issue.
be checked when choosing any particular reclosing
cycle. Also, when using instantaneous first reclosure
it is necessary that the protective relays open their
contacts within
10
cycles or less after the breaker
is tripped in order that the trip circuit will be de­
energized before reclosure takes place.
CONSTRUCTION
As shown in figure
1 ,
the RC relay consists of a
latching solenoid unit, Y, a synchronous motor driven
timing unit and an instantaneous auxiliary unit, X.
An additional instantaneous unit,
Z ,
is also provided
when specified.
T i m i n g Unit
The timing unit contains a synchronous motor and
gear train mounted behirui the front sub-base. The
gear train drives a drum with cams, which actuate
contacts 1 , 2, 3 , 4 and 1 4 . Cam 5 actuates theY unit
latch to reset the Y unit and close the Y13 contact.
Cams
# 1
and
# 2 ,
which operate contacts 1 and
2
respectively, are notched and are not intended to be
adjusted in the field.
Cam #3 is a series of flat
springs secured by screws, which can be located at
any point on the periphery of the drum. Cams
#4 and
#5
consist of screws which can be set at any point on
the periphery of the drum. Cam #14 is a single micarta
block, located to the rear of the cam #5 position and
held by a #5 cam screw.
The gear train reduction ratio is adjustable. The
drum speed dial contains indices
•.
which are lined up
with an index mark to mesh the proper gears for the
desired drum speed. A clamping screw is provided at
the edge of this dial. A push rod is located on the
front of the drum to demesh the drum and permit free
manual drum rotation.
The dial on the timing drum has 60 divisions
(second intervals with 60 second drum speed). The
edges of the #3, 4 and 5 cam slots have 12 equally
spaced white marks corresponding to 5 second in­
tervals with a 60 second drum speed.
EFFECTIVE FEBRUARY 1959
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