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Wi th the contacts ju s t c l os i ng at No . 0 t i me sett i ng, there shou l d be suff i c i ent
gap between the stat i on ary con tact bru s h an d i t s meta
approx i mate l y 1 /32 i nch w i p e .
Current Sett i ng
The m i n i mum curren t at whi ch the t i me overcurrent u n i t wi l l c l ose i t s contacts i s
determ i ned by the pos i t i on of the p l ug i n the t ap bl ock . The t ap p l ate on thi s bl ock i s
m arked i n amperes, as shown i n T abl es 3, 4 and 5 .
When the t ap sett i ng i s changed wi th the r e l ay i n servi ce, t he fol l owi ng p r ocedure
must be fo l l owed:
shorts the current transformer second ary wi n d i n g .
i t i n the t ap mark ed for the des i re d p i ckup current .
The m i n i mum current requ i red t o rotate the d i sk s l ow l y and t o c l ose the contacts
s hou l d be wi thi n f i ve percent of the val u e marked on the t ap p l ate for any t ap sett i ng
and t i me d i a l pos i t i on .
means of the spr i ng adju s t i n g r i ng .
bl ade i n the n otches aroun d the edge . By turn i ng the r i n g, the oper at i ng current of the
u n i t c an be brought i n to agreement wi th the t ap setti ng emp l oyed. Thi s adju s tment al so
perm i ts any des i red sett i ng to be obt a i ned i ntermed i ate l y between the ava i l abl e tap
s e t t i ngs .
P i ck u p adju stment by mean s of the control spr i ng app l i es to the JBCG5 1 and JBCG53
re l ays .
d i fferent procedure app l i e s to the JBCG77 r e l ays .
A
the p i ckup of the u n i t for any current t ap sett i ng i s adju s ted by means of the var i abl e
res i s tor i n the phase- shi ft i n g c i rcu i t .
sett i ng i nterme d i ate l y between the var i ous t ap sett i ng s to be obt a i n e d .
spr i ng i s prewoun d approx i mate l y 660 degrees wi th the contacts jus t c l ose d .
adju stment of thi s sett i n g i s sel dom requ i red; if i t i s requ i red, bec au se of the
i n suff i c i ent r ange of the var i abl e res i s tor, i t shou l d never be nece s s ary to w i n d up
the control spr i ng adju s ter more than 30 degrees {on e n otch) or u nwi n d i t more than 90
degrees ( three n otches ) from the f actory sett i n g .
Test connec t i ons for mak i ng p i ck u p and t i me check s o n the t i me over-current u n i t
are shown i n F i g . 2 1 .
constant frequ ency .
test i ng i nduct i on rel ays s i nce the i r use may cause a d i s torted wave form.
i n the wou n d shad i ng coi l c i rcu i t marked
b l ocked c l osed or jumpered for both the p i ck u p test and the t i me tes t .
T i me Sett i ng
The sett i n g of the t i me d i a l determ i nes the l ength of t i me the u n i t requ i res to
c l ose i ts contacts when the current reaches a predeterm i ned va l ue .
ju s t c l osed when the d i al i s set on zero.
trave l the max i mum amou n t to c l ose the contacts an d therefore thi s sett i ng g i ve s the
m ax i mum t i me setti n g .
GEK-49849
( 1 ) R emove the connect i ng p l ug; thi s de-energ i z es the re l ay and
I f thi s adju s tmen t has been d i s turbed, i t can be restored by
The r i ng can be turned by i n ser t i n g a screw dr i ver
U se a source of 120 vo l ts o r greater wi th good wave form and
S tepdown transformers or phantom l oads shou l d not be emp l oyed i n
1
back i ng str i p to e n s ure
( 2 ) R emove the t ap screw and p l ace
( 3) R ep l ace the connect i n g p l u g .
Thi s adju s tmen t a l so perm i t s any des i red
see i ntern al connect i on d i agram, mu s t be
D,
When the d i al i s set on 10, the d i sk m u s t
19
For the JBCG77 r e l ays,
The control
F urther
The cont act
T he contacts are
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