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CARRIER RELAYING
s i rab l e
t o c l e a r
i n t e rnal
du ring a n out - o f - s t e p c on d i t i on , b u t it
s o e s sent i a l
t o be ab l e t o c le a r them at h i gh
spee d .
The g r ound
r e lay t r ip c i r cu i t i s n ot
b l o c ke d by the
out - o f - s t e p
t r ip i n s t ant ly .
On pha se - t o -pha se f au l t s ;
o r
two o f the Z3 c on t a c t s w i l l r e A e t when the
s y s t e m swing s in pha se , thu s
A,
the back c on t a c t s ,
t r ip c i r cu i t w i thout
wait ing for the r e s e t of
X2 .
On a three -pha se fau l t , howe ve r , n one o f
Z 3
t he
c o n t a c t s
w i l l r e s e t , a n d c on s e quent l y ,
t r ipping
w i l l n ot
o c cur
X 2
p i rat i on of t h e
t ime
X2
i s made
p o s s i b l e
re ce i v e r r e lay back c on t a c t s ,
It w i l l be n o t e d
f r om
back-up
t r ipp i n g
thr ough
b l o cke d by the
out - o f - s t e p c on t a c t s ,
c a s e , b a c k -up p r ot e c t i on on three -pha se fau l t s
du ring
out - o f - s t e p
i s
�
r range d , howe ve r ,
s o that T3 c onne ct i on
be made
on the other
c ont act s , a n d i n thi s c a s e , t r i�ping o n
o f - s t e p
c annot
be pre vented
l onge r than the t ime s e i . [. ing o f T3 .
ADDITIONAL CARRIER CHANNEL USES
In add it i o n t o r e laying de s c r ib e d ab ove , the
c a r r i e r
channe l
can be
t i ons
such a s
t e l eme t e r i n g
c ommuni c at i o n ,
supe rv i s o ry c ont r o l and remote
t r ipping .
For
the se
l e ad f r om the p l ate is b r ought out thru a back
K3
c on t a c t
to the aux i l iary s t art
in
shown
F i gu r e l .
Thi s ar rangement
independent
ke ying c on t a c t
the othe r
fun c t i o n s .
g i z e d b y the r e lay
s t ar t c ont a ct s
the aux i l iary
s t art c on t a c t
thB var iat i on
in p l a t e v o l t age o f t he o s c i l l
at o r tube t o a minimum .
In o r d e r t o prevent the
r inging
during the t ime c a r r i e r i s be ing u s e d
f o r aux i l iary
t e l eme t e ring func t i o n , t h e t ime
de lay c i r u c i t
o f F i gu r e
t e rmina l .
Thi s c i r cu i t
nat i on o f re s j_ s t o r s and
thru c on t a c t s
o n an
aux i l iary type TV r e l ay .
fau l t s o c cu r r in g
i s n ot
X 2 ,
r e lay ,
and can
one
a l l ow ing
one of
C
B ,
or
t o c omp l e t e the
unt i l aft e r the e x
de lay .
The r e s e t
o f
by
t h e opening
o f the
RRB .
Figure l
that
the
D,
and T3 i s shown
i n which
n o t p o s s ib l e .
It
i s
can
s i de o f the out - o f - s t e p
out -
f o r a p e r i o d of
u s e d for other fun c -
c ont r o l ,
l oad
fun c t i on s ,
a
separate
c on t a c t s as
p r ovide s
f o r r e laying
and
K3
The
re lay i s
e n e r
t o open up
in o r d e r t o ke ep
c a r r i e r
a larm f r om
3
can be u s e d at e a ch
c on s i s t s
of a c omb i
capa c j_ t o r·
e n e r g i z e d
1<
\-Jher t e leme t e r i n g impu l s e s
r e c e i v e d , t h e c o i l o f t h e t y p e TV r e lay i n the
r e c e i v e r
p l at e c i r cu i t
impu l s e .
Thi s cau s e s the n o rma l ly c l o s e d c on
t a ct , TV, t o a l t e rnat e ly
g i z ing che
c i r cu i t thru a
In p ar a l l e l
cap a c i t o r .
i s a c i r cu i t c on s i st in g
AL
c o i l
of the c ar r i e r a l a rm e l ement .
s i st o r s and cap a c i t. o r s
t h i s
part i cu l ar
c a s e
2
app r o ximat e ly
s e c on d s
w i l l
p r e vent
ope rat i o n on the l onge s t
me t e r ing impu l s e .
The a l arm be l l
can
s t an t an e ou s ly
whe ne ve r the r e lays
r i e r by u s in g the type
the c a r r i e r
re lay s t art c i r cu it w i t h it s back
c ont a c t in the a l arm c o i l c i r cuit .
If
it i s de s i r e d
t o s i gna l by me an s of the
�u sh but t on ,
i t i s o n ly ne c e s sary t o ho ld the
p u sh but t on c l o s e d for a p e r i od l ong e n ough t o
cau s e
the
a l arm
e l ement t o d r op out .
g i z in g c a r r i e r thru
the pm;h but t on maint ain A
t he n o rma l ly c l o s e d c on t a c t , TV,
t he charge
on the capac i t o r
a l arm e l ement
w i l l d r op out ,
c on t a c t marked " a larm" and cau s in g the be l l t o
s ound .
By p r ope r ly p r oport i on in g the r e s i s t o r
and cap ac i t o r , a w i d e range of d r op - out
can be obtained f o r the a l arm e l ement .
The a l arm
b e l l can
s t ant ane ou s ly
whe n e ve r the
r i e r
by u s i n g the
type
i n
the c ar r ie r
r e lay s t art c i r cu i t w it h
b a ck c on t a c t i n the a l arm c o i l c i rcuit .
Eme rgency
p o int -t o -p o int
n o rma l ly supp l i e d
with
e qu ipme nt .
Thi s
can be
han d s e t
at the
c a r r i e r
swit chb oard ,
or f r om
w i re d t o the e qu ipment .
o f
c ommun i c at i o n i s emp l oyed whe r e the ope r a
t o r
pushe s a s w i t c h
o n
c a r r i e r a n d c on n e c t t h e mi c r ophone t o t h e c a r -
r i e r
t ran smit t e r .
pe r i od ,
the ope rat o r
Whe n e ve r
the hand s e t
a r e be ing sent
o r
i s e n e r g i z e d
on e a ch
open and c l o s e e ne r -
r e s i st or and
w i t h t h i s
capa c i t o r ,
o f
d
re s i st o r and the
The r e -
are cho sen s o that f o r
a max imum
d e lay of
can be obt a ine d . Thi s
t e le
be made
t o operate in
s t a r t car
PG
r e lay
c on n e c t ing in
Ene r
open and when
i s u s e d up ,
the
c l o s in g it s back
t ime s
be made
t o ope rate in
r e l ay s s t art c a r
PG
r e l ay
c onne ct ing
i t s
c ommun i cat i on
i s
the c a r r i e r
re laying
done by p lugging
a
s e t ,
at the
re lay
a
de sk set pe rman e n c l y
The p u sh - t o - t a l k type
t h e han d s e t t o s t a r t
Dur i n g
t h e
l i s t e n in g
swit ch .
r e l e a se s
t h e
i s p lugged in o r l i f t e d
7
a
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