GE K-49861
C I RCU I T DESCR I PT I ON
The
F i g u r e s
bo t toms
r e lay s .
V I I .
i nt e r na l connec t i ons for types SLY8 lA and SLY 8 lB a r e shown i n
2 and 3 r e spe c t i v e l y .
The t e rm i na l numbe r s a t the t op s and
of these d i ag r ams r ep r e s ent the e x t e r na l conne c t i ons t o the
The e x t e r na l connec t i ons can be g r ouped a s shown in Table
TABLE VI I
EXTERNAL CONNECT I ONS
TERMINAL NUMBERS
DESCRIPTION
1 through 6
7 and 8
9
10
11 through 13
14 through 18
15 through 17
19 and 20
AC current inputs
MOB output contact (SLY81B only)
Trip contact {other end connected to #19)
Surge ground
Trip contact with target seal-in
Trip contact with target
AC potential inputs
DC control power input
The l i ne - t o- l i ne i nput vol tages a r e conne c t ed to the p r ima r i e s o f
s t ep down pot ent i a l t r ans forme r s ( TA, Ta, a n d Tc ) . T h e s e conda r i e s o f
t h e s e pot ent i a l t r ansforme r s a r e connec ted to t h e s i gnal p r oce s s i ng
( SP ) c a r d a s we l l a s to a t h r ee-gang po tent i ome t e r .
The vo l t ag e s on
the s l i de r s of the pot ent i ome t e r s a r e also conne c t ed as i npu t s t o the
SP ca r d .
The
i npu t
pha s e
cu r r e n t s
pa s s
t h r ou g h
t h e
p r i ma r i e s
o f
t r ansac tor s
( XA,
Xa and Xc ) .
The t r ansa c t o r s p r oduce s e conda r y
vol t a g e s
p r opo r t i onal
t o
t he i r
p r i ma r y
cu r r e n t s
i n mag n i t u de;
howev e r ,
the
s e conda r y
vol t a g e s
l e ad
t h e i r
r e spec t i v e
p r i ma r y
cu r r e n t s by a phase ang le of 8 5° .
Taps a r e p r ov i ded on the pr i ma r i e s
o f t h e s e t r ansacto r s and the seconda ry vo l tag e s a r e connec t ed a s
i npu t s t o the S P card .
TABLE VI I I
OUTPUTS FROM SP CARD
OUTPUT SIGNAL FROM SP CARD
INPUT TO CARD
VAB. ABC. VCA
{IA - IB)ZR1 X CAtt
{IB - IC)ZR1 X CBtt
(IC - IA)ZR1 X Cctt
(IA - IB)ZR1 - TVAB
(IB - Ic)ZR1 - TVBC
(IC - IA)ZR1 - TVCA
Combined Polarizing {CP)
Coincidence Logic (CL)
Operate Signal {OS)
tt
CA, CB, Cc are constants which are adjustable from
approximately 0 to 0.9 to permit adjustment of overcurrent
supervision.
11
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