B Eari N G A N D Contacts; R E N Ewal Parts - GE IAV51A Instructions Manual

O n t h e u nd e r - a n d overvoltage rel ays, such a s t h e I AV 5 3A, I AV 5 3 B , I AV 5 3 C, I AV 5 3 D ,
IAV 5 3 K , IAV 5 3 L, IAV53 M , a n d I AV 5 3 N , t h e o pe rati ng voltage f o r a g i v e n ta p s etti n g i s t h e
m i n i m u m v o l t a g e a t wh i c h t h e l eft- h a n d contacts cl ose . T h e r i g h t- h a n d conta cts w i l l t h e n
cl ose at a certa i n p e rcenta g e o f op erati ng volta g e .
p e rcentag e, t h e rig ht- h a nd m ovi n g contact m a y b e rotated o n t h e s h aft aft e r f i rst
l oose n i ng th e c l a m p i n g screws that h o l d it i n p l a ce . C h a n g i n g t h e positi o n of t h i s ( r i g ht)
co ntact provi d e s a means of adj ust i n g the volta g e that cl oses the r i g h t- h a n d contacts t o a
setti ng between 50% a n d 9 5 % of the volta g e needed to cl ose t h e l eft- h a nd contacts.
C h a ng i ng the posi ti on of the r i g h t- h a n d contacts a l so c h a n g es the v o l ta g e a t wh i ch t h e
l eft- h a n d conta cts cl ose, h owever.
preced i n g p a ra g r a p h ) a n d r i g ht conta cts m ust b e ma d e to obta i n a d esi red c h a r a cte r i st i c .
TI M E S E TT I N G
T h e t i m e o f o pe ra t i o n o f t h e ove rvo l ta g e rel ays i s dete r m i ned p r i m a r i l y b y t h e s etti n g of
the ti m e d i a l , w h i l e that fo r the u nd e r- and ove rvolta g e r e l ays is d et e r m i n ed by th e s p read
of t h e co ntacts, a s expl a i ned u n d e r VO LTAG E S E TTI N G . F u rt h e r adj u st m e nt i s o bta i n ed by
moving t h e p e r m a n e n t mag n et a l ong its s u p p o rti ng s h e l f ; movi ng t h e m a g net in towa rd
th e back of t h e relay d e creases t h e t i m e , wh i l e m o v i n g it o u t i n creases t h e t i m e .
F i g u re 1 2 sh ows t h e t i m e/voltage c h a ra cte r i stics o f th e Type I AV 5 1 A a nd I A V 5 2 A r e l a ys,
with the d ia l setti ng fo r o bta i n i n g each cha ract e r i st i c . To m a k e t i m e sett i ngs, s et t h e t i m e
d i a l to t h e n u m be r r eq u i red ( t o g i v e th e d esi red cha racte ristic) b y t u r n i n g it u nt i l t h e
n u m b e r l i nes u p with th e n otch i n t h e adjacent fra m e . T h e t i m e i nd i ca ted b y t h e cu rves i s
th e ti m e req u i red t o cl ose t h e r e l a y contacts w h e n th e volta g e i s s u d d e n l y i ncreased f r o m a
va l u e b e l ow p i ck u p to t h e va l u e o n the c u rve.
F i g u re 1 3 sh ows t h e c h a racte rist i cs of the IAV53A and I AV 5 3 K , a nd I AV 5 3 B a nd I AV 5 3 L
rel ays. T h e ti me c h a racterist i c of th e re l ay i s a u tomatica l l y d et e r m i n ed b y t h e sett i n g o f t h e
rat i o o f t h e volta g e t o c l o se t h e r i g h t conta cts t o th e voltag e t o cl ose t h e l eft c o n ta cts.
F i g u re 1 4 sh ows the t i m e /volta g e cha racte ristics of th e Type IAV 5 3 D a nd I AV 5 3 N r e l a ys. N o
cu rve i s g iv e n for th e Type IAV53C a nd IAV53 M : th ei r t i m e /voltage c h a ra ct e r i stics a re
exp l a i ned u n d e r t h e sect i o n h e a d i ng
The ti m e /v o l t a g e ch a racteristics a re p l otted in percent, th u s ma k i ng th e m a p p l i ca b l e for a l l
tap sett i ngs.
B E A R I N G A N D CONTACTS
S e e
PERIODIC CH ECKS AN D MAI NTE NANCE.
It is reco m m e n d ed that suff i c i e nt q u a ntiti es of ren ewa l pa rts be ca rried i n stock to e n a b l e
th e pro m pt r e p l a ce me nt o f a ny that a r e worn, b r o k e n o r d a m a g ed . Pa rts b u l l et i n n u m b e r
G E F - 3 8 9 7 g i ves a l i st o f th ose m ost s u bject t o wear i n o rd i n a ry o p e rati o n a nd m ost l i k e l y t o
be d a ma g e d d u e t o poss i b l e a b n o r m a l cond i t i o n s.
When o rd e r i ng re newa l pa rts, add ress th e n ea rest Sales Off i ce of the G e n e r a l E l e ct r i c
C o m p a ny, s pecify t h e q u a ntity a n d th e n a m e o f th e p a rt wanted, as sh own i n F i g u re s 1 5
a nd 1 6, a n d g i ve com pl ete na m e p l ate d ata , i nc l u d i n g se r i a l n u m b e r .
G e n e r a l E l e ctr i c Com pa ny's req u i siti on o n w h i c h the r e l ay was f u r n i s h e d .
G E H - 1 8 1 4
H e nce, s i m u l t a n e o u s adj u stme nts f o r cl osi n g l eft ( s e e
CHARACTERISTICS.

R E N EWAL PARTS

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I f it i s d e s i red t o c h a n g e t h i s
I f poss i b l e g i v e t h e