Westinghouse RC Instructions Manual Download

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TYP E RC AUTOMATIC R E CLOSI N G RELAY

OPERATION

Operation of the relay and associated equipment

will be described, using the external schematic in

figure 7, in conjunction with figures 4 and 5, which
show contact positions as a function of the drum posi

tion.  Fi gure  5  is  based  on  the  factory  cam  adjust
ment-immediate ,  15  and  45  second  reclosures,  with
one  drum  revolution  in  60  seconds.  It  is  further  as
sumed  in  figure  5  that  the  instantaneous  trip  is  locked
out  after  the  first  reclosure ,  and  the  fault  is  not

cleared prior to lockout.

Motor Control

Motor energization is controlled by cams 1 and 2.

the start position the motor is energized through

1t1  and  52b  contacts  when  the  breaker  opens.  As  the
drum  moves  away  from  the  start  position,  1t2  contact
closes  to  energize  the  motor  through  the  52a  contact
during  the  time  that  the  breaker  is  closed.

the

breaker  is  closed  at  the  lockout  position  the  drum
will  continue  to  rotate  until  the  1t2  contact  opens  at
the  start  position.

the breaker is open, the drum

will stop in the lockout position, since the 1tl, 52a

and Y7 contacts are all open at this point.

Contact Y7 keeps the motor energized when the

breaker remains closed after an immediate reclosure

until the #2 contact can close. For this condition,

5 2b opens before the drum can rotate sufficiently to

close the #2 contact. Contact Y7 has no significance

during subsequent reclosing operations.

C l o si n g S eq uencing

The number o f reclosures_ and the time at which

they occur is determined by the location of the #3 cam
screws , which close the #3 contact.

Insta ntaneo u s T rip L o ck o u t

A s shown i n fi gures 5 and 7 , the trip circuit o f

the instantaneous tripsunits i s opened b y Y13 and

14 contacts from the time of the first reclosure until
the drum returns to the start position. During the

initial reclosing, contact Y13 is opened and remains

open  until  the  Y  unit  is  completely  reset  at 6  seconds.
The  purpos e  of  contact  Y13  is  to  keep  the  trip  cir
cuit  open  until  cam  contact,  14 ,  can  be  o pened  by  the
drum rotation.  Contact  Y13  has  no  significance  during
subsequent reclosing  operations.

X-Y

C irc uit

Referrin g to fi gure 7, when the breaker close cir

cuit  is  energized  through  5 2bb,  Y5  and  #3  contacts,
the  7 9X  coil  is  also  energized.  Then,  X8  and  X9
contacts  seal  around  the  Y5  contact  and  energize

79Y coil, respectively.

Contact Y5 opens and re

mains open until the Y unit is completely reset at 6

seconds.  As  the  breaker  closes,  52bb  contact opens,
de-energizing  the  X  and  Y  coils.  Should  the  breaker
immediately  trip  again,  contacts  Y5  and  X8  will  be

open to prevent premature energization of the breaker
close circuit.

C o m p l ete

p erati ng S eq uence

Fault-Trip - Immediate Reclosure

Refer to figure 7. With the timing drum in the

"Start"  position,  a  #3  cam  spring  will  be  holding
contact  #3  closed.  The  breaker  switch  contacts  52b
and  52bb  close,  energizing  the  motor  79M  through

contact  # l ,   and  th e  drum  begins  to  rotate .  At  the
same  time  the  coil  of  the  contactor  unit,  79X,  is  en
ergized  through  drum  contact  #3,  contact  Y5,  and
inte gratin g   lockout  c ontact  9A,  when  used.  When
the  breaker  latch  checking  switch ,  52LC,  closes ,  the
breaker  control  relay  52X  is  immediately  energized
through  the  preclosed  contacts  Y5  and  3.  This  in

turn  energizes  the  closing  coil  of  the  breaker,  52C.
Simultaneously,  contactor  unit,  7 9X,  seals  in  through
its  contact  X8,  while  its  other  contact,  X9,  energizes
the  coil  of  solenoid  unit  79Y  to  open  contacts  Y5  and
Y13  and  close  contacts  Y6  and  Y7.  As  the  circuit
breaker  closes,  the  breaker  auxiliary  switches  52b
and  52bb  open,  and  52a  closes.  Opening  52bb  de
e nergizes  79X  and 79Y.  The  latter then resets against

its  latch  to  open  contact  Y6  and  remains  in  this  posi
tion,  thus  leaving  contacts  Y5  and  Y13  o pen  and
contact  Y7  closed  until  the  latch  is  released.  Before

the latch is released, th e drum-operated contact, 14,

will be

opened

and will

remain open until the

drum

returns to the "Start" position.

Preparing for Second Reclosure

The drum continues to rotate, since the motor is

energized through Y7.

When the breaker trips the

second time,  no  immediate  operation  occurs.  At  about
one  second, 1t2  cam  contact  closes  to  set  up  the  motor
circuit  when  the  breaker  is  s ubsequently  reclosed.  At

about the three second drum position contact 1t3 opens.
At about

seconds, the Y unit latch is released by

the 1t5 cam, resetting the Y unit. The relay is now
ready for another reclosure as soon as contact 1t3 is

closed by the 1t3 cam spring. The drum will continue

to rotate, since the motor is energized through 52b

and

1t1

contacts.

Second and Third Reclosures

At 15 and 45 seconds the #3 contact closes to

reclose the breaker. After each reclose, the Y unit

is unlatched by the action of cam #5 .