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C ON TACT CLEAN ING
For cl eanin g r e l ay contacts, a flexib l e b urni sh in g to ol shou ld b e used. Thi s consi sts of a
fl exib l e str i p of meta l with an etch-r oughen ed sur face r esemb lin g in effect a su per fin e fi l e.
The polishin g acti on i s so d e li cate that n o scr atches ar e l eft, yet it wi l l c l e an off an y
corr osi on thor o u g h ly an d r a pi d ly. Its flexibi lity ensur es the cleanin g of the act u a l points of
con tact.
Do n ot use knives, fil es, abr asive paper , or cl oth of an y kin d to c l e an r e l a y
con tacts.
*C OVE R CLE AN ING
The Cl ear L ex an® cover should b e cl ean ed with a soft cloth and w ater on ly. N o cl ean in g
sol ution s should b e used. U se of cleanin g sol ution s may damage the clear cover.
SY STE M TE ST
Alt h ou g h this instr uction book i s pr i mar ily wr itt en to check and s et t h e I FC r elay , ov erall
fun ction al tests to ch eck t he system oper ation ar e r ecommend ed at int erva ls bas ed on the
custom er' s ex per ien ce.
TI M E- OVE RCU R RENT UN IT
If it is found d ur in g installation or per i odi c testin g that the ti me-over curr ent un it is o ut of
l i m its, th e un it may be r ecal ibr ated as foll ows:
R otat e th e time d ial t o t he z er o (0) position and check , by means of a la mp, that th e
conta cts j ust cl ose.
The poin t at w h ich the contacts j ust cl ose can b e adj usted by runn ing t he stat i onary
con tact br ush in or out by means of its adj ustin g s cr ew.
W ith t he cont acts j ust clos in g at t he z er o (0) t i me-d ial sett in g , th er e sh ould b e suff icient
g a p b etw een th e station ar y cont act bru s h and it s m et al ba ck ing str ip t o ensur e
a ppr ox i mately 1/3 2-inch w i pe.
Th e p i ck up of the un it for an y curr ent-tap set ting is adj ust ed by m e ans of a spr ing
adj usting r ing. By turn ing the r in g the oper atin g curr en t of th e un it m ay b e br o ught int o
agr eemen t w ith the ta p settin g employed if, _for some r eason , th is adj ust ment has b een
d isturb ed. Th is adj ustment also per mits any desir ed setting inter med i at e b etw een t he
var ious ta p settin gs to b e obtain ed. I f such adj ustment is r equ ir ed, it is r eco m m end ed t h at
the h i g her ta p setting b e used. It should b e n oted that t he r el ay w ill n ot n ecessar ily a gr ee
w ith th e time curr ent char acter istics of Fi g ur es 5 an d 6 if the r el a
p i ck u p at a val ue oth er than tap v al ue, b eca use the torq u e l eve of th e r elay has b een
chan g ed.
C onn ect the oper atin g-coi l ter m in a ls to a sour ce of the pr o per fr equ en cy , g ood w avefor m,
and an a m pl itud e of 1 1 0 volts or h i g h er , usin g re sist an ce l oad b ox es for th e s ettin g curr ent
(see the test cir cu it in Fi g ur e 1 1 ).
® Register ed Tr ademark of G en er a l E l ectri c C o m pan y
* Revised since l ast i ssue
GEK-49950
SERVICING
15
r
h as b een adjust ed t o
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