GEK-49848A
TABLE 1 1
TARGET AND S EAL- IN UN I T OPERATING CURRENTS
PI CKUP
DROPOUT
CURRENT
CURRENT
0 . 2
0 . 1 15- 0 . 1 95
0 . 05 OR MORE
2 . 0
1 . 15 - 1 . 95
0 . 50 OR MORE
TIME OV ERCURRENT UN IT
Rotate the t i me d i al s l owl y and check by means o f a l am p that the contacts jus t
cl ose at the zero t i me d i al s etti n g .
Where the contacts jus t cl ose can be adjus ted by runn i n g the s ta t i onary contact
brus h i n or out by mea n s of i ts a djusti n g screw . Th i s screw s houl d be hel d securel y
i n i ts support .
Wi th the contacts jus t cl os i n g a t No . 0 t i me setti n g, there s houl d be
suffi c i ent ga p between the stati onary contact brus h and i ts metal backi n g stri p to
ensure a pproxi matel y 1/32 i nch wi pe .
Current
The m i n i mum curren t at whi ch the t i me overcurrent un i t wi l l cl ose i ts contacts
i s determi ned by the pos i ti on of the pl ug i n the ta p bl ock . The ta p pl ate on thi s
bl ock i s ma rked i n amperes, a s s hown i n Tabl es 2, 3 and 4 .
When the ta p sett i n g i s c han ged wi th the rel ay i n servi ce, the fol l owi n g
procedure mus t be fol l owed:
( 1 ) remove the connecti n g pl ug; thi s de-energi zes the
rel ay and s horts the current tra n s former secondary wi nd i n g .
( 2 ) remove the ta p
screw and pl ace i t i n the ta p marked for the des i red pi ckup current . ( 3 ) repl ace
the connec t i n g pl ug .
The mi n i mum current requi red to rotate the d i sk s l owl y and to cl ose the
contacts s houl d be wi thi n fi ve percent of the val ue ma rked on the ta p pl ate for any
ta p sett i n g and t i me d i al pos i ti on . I f thi s adjus tment has been d i s turbed, i t can
be restored by means of the s pr i n g adjusti n g ri n g .
The ri n g can be turned by
i nsert i ng a screw d r i ver bl ade i n the notches around the edge . By turn i n g the ri n g,
the o pera t i ng current of the un i t can be brought i nto a greement wi th the ta p sett i n g
empl oyed.
Thi s adjustmen t al so permi ts any d e s i red sett i ng t o be obta i ned
i ntermed i atel y between the a va i l a bl e ta p setti n gs .
P i ckup adjus tment by means of the control s pri n g a ppl i es to the JB C51 and JBC53
rel ays . A d i fferent procedure a ppl i es to the JBC7 7 rel ays . For the JB C77' rel ays,
the pi ckup of the un i t for any current ta p sett i n g i s adjus ted by means of the
vari a bl e res i stor i n the phas e- s h i ft i n g ci rcui t . Th i s adjus tment al so perm i ts any
d e s i red sett i n g i ntermed i atel y between the va ri ous ta p sett i ngs to be o bta i ned . The
con trol s pri ng i s prewound a ppro x i matel y 660 de grees wi th the contacts just cl osed .
Furt he r adjus tment of thi s sett i ng i s sel dom requi red; i f i t i s requi red, because o f
i n suffi c i ent ran ge of the va ri a bl e res i s tor, i t s houl d never be necessary to wi nd up
the control s pr i n g adjus ter more than 30 degrees ( o ne notch ) or unwi nd i t more than
90 de grees ( t hree notches ) from the factory setti n g .
1 7
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