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Westinghouse

t. L. 41 -661 C

INSTALLATION

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OPERATION

•

MAINTENANCE

I N S T R U C T I O N S

TYPE RC AUTOMATIC RECLOSING RELAY

C A U T 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 s e e that they are clean and c lo se prop
erly , and operate the relay to check the settings and

electrical c onnections.

AP P L I C A T I O N

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 re lay action. The relay
may be adjusted to p rovide several reclosures at pre

determined time intervals, so that in case the breaker

does not remain closed after the first reclosure addi

tional  reclo sures  will  be  made.  The  first  reclo sure
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  reclosure s ,   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 reclo sure must be made by manual opera
tion of the control switch. However, if the breaker

remains c losed 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 rec losures follo wing the next tripping of

the breaker.

For any automatic reclosing application, the de

ratin g factors for breaker interruiJting ability should

SUPERSEDES I . L. 41 -661

* Denotes change from s uperseded i ssue.

be checked when choosing any particular reclosing

cycle.  Also ,  when  using  instantaneous  first  reclo sure
it  is  neces sary  that  the  protective  relays  open  their
contacts  within

cycles or less after the breaker

is tripped in order that the trip circuit will be de
energized before reclosure takes plac e .

CO N S T R U C T I O N

As shown in figure 1 , the RC relay consists of a

latching s olenoid unit, Y , a synchronous motor driven

timing unit and an instantaneous auxiliary unit,

An additional instantaneous unit,

is also provided

when specified.

T i m i n g U ni t

· The timing unit contains a synchronous motor and

gear train mounted behirui the front sub-base. The
gear train drives a drum with c ams, which actuate

contacts  1 ,  2, 3 ,  4  and  1 4 .   Cam  5  actuates  the  Y  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  sin gle  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

6 0

divisions

(second intervals with

second drum speed). The