GEH-1 8 1 4
T IME SETTING
The time of operati on of the overvol tage rel ays i s determi ned pri mari l y by the setti ng of the time
di al , whi l e that for the under-and overvol tage rel ays i s determi ned by the spread of the contacts as ex
pl ai ned under VOLTAGE SETT I N G . Further adjustment i s obta i ned by mov i ng the permanent magnet al ong i ts
supporti ng shel f ; movi ng the mag net i n toward the back of the rel ay decreases the ti me wh i l e movi ng i t out
i ncreases the ti me .
Fi g . 12 s hows t he t i me-vol tage characteri stics o f the Type IAV51A and IAV52A rel ays wi th the d i a l
setti ng for obta i ni ng each characteri s ti c . T o make time setti ngs , s e t the time d i a l to the number re
qui red ( to gi ve the des i red characteri sti c ) by turni ng i t unti l the number l i nes up wi th the notch i n the
adjacent frame . The ti me i ndi cated by the curves i s the time requ i red to cl os e the rel ay contacts when
the vol tage i s suddenly i ncreased from a val ue bel ow pi ckup to the val ue on the curve .
Fi g . 13 shows the character i s ti cs of the Type IAV53A and IAV53B rel ay . The time characteri s ti c of the
rel ay is automati cal l y determi ned by the setti ng of the ra ti o of the vol tage to c l os e the right contacts
to the vol tage to c l ose the l eft contacts . Fi g . 14 shows the time-vol tage characteri s ti cs of the Type
IAV53D rel ay . No curve i s gi ven for the Type IAV53C s i nce i ts time-vol tage characteri s ti cs are expl ai ned
under the secti on headi ng CHARACTER I ST I CS .
The time-vol tage characteri s ti cs are pl otted i n percent thus mak i ng them appl i cabl e for a l l tap
setti ngs .
B EARI NG AND CONTACTS
See MAI NTENANCE .
RENEWAL PARTS
It i s recommended that suff i c i ent quanti ties of renewal parts be carri ed i n s tock to enabl e the prompt
repl acement of any of those worn , broken or damaged . Parts bul l eti n number GEF-21 49 gi ves a l i st of those
mos t subject to wear i n ord i nary operati on and to damage due to pos s i b l e abnormal cond i ti ons .
When orderi ng renewal parts , address the neares t Sal es Offi ce of the General E l ectri c Company , s pec i fy
quanti ty requ i red , name of part wanted as shown by Figs . 15 and 16 , and g i ve compl ete namepl ate data ,
i ncl udi ng seri al number . I f possi b l e g i ve the General E l ectric Company ' s requi s i ti on on wh i ch the rel ay was
furni shed .
1 1
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