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The Type JBCG relays are groun d d i rect i on a l overcurrent relays t h at are us ed
pr i mar i ly for the protect i on of feeders and tran s mi s s i on li nes .
wi t h i nverse, very i nverse, or extremely i nver s e t i me char acter i st i cs .
A ll the JBCG relays con t a i n a t i me overcurrent un i t of the i nduct i on d i sk type,
an i n stantan eous overcurrent cup type un i t, and an i n st ant aneous d i rect i on a l cup
type un i t .
The d i rect i o n a l un i t can be poten t i al polar i zed, current polar i zed, or
both, and i t d i rect i on ally controls the oper at i on of both the t i me overcurrent d i s k
un i t a n d the i n stantaneous cup un i t .
Those relays h avi ng the des i gn at i on Y lA followi ng the model number also cont a i n
a H i - Se i smi c i nstantaneous un i t of h i nge d armature construct i o n .
d i rect i onal and h as a self-co n t a i ned hand reset t arget t h at w i ll show whenever the
un i t h as oper ate d .
Two tar get sea
coi l of e ach of these un i ts r e s pect i vely i s con nected i n s e r i es w i t h the con t acts of
the t i me overcurrent un i t an d the i n stan t aneous overcurrent un i t .
each seal- i n un i t respect i ve ly are con n e cted i n p ar allel w i th the con t acts of the
t i me over current un i t and the i n stant aneous overcurrent un i t to pro vi de protect i on
for them and the associated control s pr i n g .
A ll the JBCG relays are mounted i n standard L 2 s i ze d r awout cas es; t h e outli n e
a n d panel dri lli ng d i me n s i ons f o r wh i ch a r e shown i n F i g. 25 .
for t h e relays are s h own i n F i g . 5, 6 a n d 7 .
by F i g .
8 an d 9 .
t h e 51, 53 and 77 models .
27 .
These instructions do not purport to cover all details or variations in equipment nor to provide for
every possible contingency to be met in connection with installation,
further information be desired or sho uld particular problems arise which are not covered sufficiently for
the purchaser's purposes,
To the extent required the products described herein meet applicable ANSI,
but no such assurance is given with respect to local codes and ordinances because they vary greatly.
GEK-49849
G ROUND
O V ERCURR ENT
G R O UN D DIR ECTIO N AL O V E R C U R R E N T R EL A YS
TYP ES:
D ESCRIPTION
1-
i n un i t s are provi ded i n each o f the relays.
The JBCG52, JBCG54 and the JBCG7 8 are daub
The i nternal connect i on d i agr ams are shown i n F i g . 26 and
the matter should be referred to the General Electric Company.
DIR ECTIONAL
R ELAYS
JBCG51M
JBCG5 1M (- ) Y 1A
JBCG5 3 M
JBCG5 3 M (- ) Y lA
JBCG7 7 M
Typ i cal external connect i o n s are shown
operation or maintenance.
3
JBCG52M
JBCG5 4 M
JBCG7 8 M
They are avai lable
Th i s un i t i s non
T h e operat i ng
The cont act s of
I nternal connect i on s
1
1
e cont act re
Should
NEMA
IEEE and
standards;
ays of
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