GEK-49848A
l oosen i n g the l a rge hexagonal nut on the bottom o f the un i t and turn i n g the core by
mea n s o f the s l otted bea r i n g s c rew . Th i s screw s houl d be hel d securel y i n pos i t i on
when the nut i s ret i ghtened .
Kee p i n mi nd that currents o f these ma gni tud es wi l l cause the c o i l s to overhea t
i f l e ft on too l on g . Therefo re, l eave the test current on onl y for short i n terval s
a nd al l ow suffi c i ent t i me between tests for the coi l s to cool .
After the torque adjustment has been ma de, the s pi ral s pri n g s houl d be set to
have ba rel y enough ten s i on to sw i n g the mov i ng contac t a rm aga i nst the sto p screw
when the un i t i s de-energi zed . Suffi ci ent ten s i on wi l l be o bta i ned i f the adjus t i n g
r i n g i s rotated a bout one- hal f
i nch from t h e neutra l
pos i t i on
i n the
coun tercl ockw i se d i rect i on, as mea sured on the peri phery of the r i n g .
Cl utch Adjustmen t
The connec t i on s s hown i n F i g . 24 for the pol a r i ty check can al so be used i n
maki n g the cl utc h adjustmen t . The 5 0 ohm fi xed res i s tor s houl d be re pl aced wi th a n
adjusta bl e re s i s tor c a pa bl e o f prov i d i n g the current ra n ge
1
i s ted i n Tabl e 1 3 for
the rel ay type and ra t i ng i n que s t i on .
A sc rew, project i ng from the s i de of the
mov i n g contact a rm, control s the c
1
utch pre s sure, a nd consequen tl y, the curren t
v a l ue wh i c h wi l l cause the cl utc h to s l i p . Wi th rated freque ncy a nd a t ra ted vol ts,
the c l utch s houl d be set to s l i p wi thi n the l i m i ts l i s ted i n Ta bl e 1 3 .
In a l l
cases, the current i s i n phase w i th the vol tage .
TABLE 1 3
D I R ECT IONAL UN I T CLUTCH ADJ USTM ENT
S UDD ENLY APPLI ED CURRENT
S UDD ENLY APPLI ED C URRENT
RATING
CLUTCH MUST NOT SLI P (AM PS )
CLUTCH MUST SLI P ( AMPS )
1 .5/12
9
1 1
2/1 6
9
1 1
that too frequent or too l ong a ppl i c a t i on o f these curren ts wi l l overhea t the
i l s .
I NSTANTANEOUS OVERCURRENT UNI T ( D I RECTIONALLY
The s ect i on
und er S E RV I CING, D I R ECTI ONAL UN I T, al so a ppl i es to the
bea ri n gs of the i n stantaneous overcur rent uni t .
and Stator
The sec t i on
and Stato r und er D I R ECT I ONAL UN I T, a l so a ppl i es to the cup and
sta tor of the i n stantaneous overcurrent un i t .
25
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