GEK-49950
C ONTACT CLEAN ING
For cleanin g relay contacts, a flexib le b urnish ing to ol shou ld b e used. This consists of a
flexib l e str i p of metal with an etch-r oughen ed surface resemb ling in effect a su perfin e fi l e.
The polishin g acti on is so deli cate that no scr atches ar e left, yet it wi l l clean off an y
corrosi on thoroughly and rapi d ly. Its flexibi lity ensur es the cleaning of the actual points of
contact. Do not use knives, fil es, abrasive paper , or cloth of any kind to clean r e l a y
contacts.
*C OVE R CLEAN ING
The Clear L ex an® cover should b e clean ed with a soft cloth and w ater on ly. N o clean ing
sol utions should b e used. Use of cleaning sol utions may damage the clear cover.
SYSTE M TEST
Alt h ou g h this instr uction book is pr i mar ily wr itten to check and s et t h e I FC r elay , overall
fun ction al tests to ch eck t he system oper ation are r ecommended at interva ls based on the
customer's ex per ien ce.
SERVICING
TIM E- OVE RCU RRENT UN IT
If it is found d ur in g installation or per i odic testin g that the ti me-over current un it is out of
l im its, the un it may be r ecal ibrated as foll ows:
Tests
R otate the time d ial t o t he z er o (0) position and check , by means of a la mp, that the
conta cts j ust close.
The point at w h ich the contacts
close can be adj usted by runn ing t he stat i onary
contact br ush in or out by means
its adj usting s cr ew.
W ith t he contacts j ust clos in g at t he zer o (0) t ime-d ial sett ing, ther e should b e suff icient
g a p b etw een the station ar y cont act bru sh and it s met al ba ck ing str ip t o ensur e
a ppr ox i mately 1/3 2-inch w i pe.
The pick up of the un it for any curr ent-tap setting is adj ust ed by means of a spr ing
adj usting r ing. By turn ing the r in g the oper ating current of the un it may b e bro ught into
agr eement w ith the tap settin g employed if, _for some r eason , th is adj ust ment has b een
d isturbed. This adj ustment also per mits
desired setting inter med i at e b etween t he
var ious tap settin gs to b e obtained. If such
is r equ ired, it is r ecommended t h at
the
ta p setting be 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
time curr ent char acter istics of
5 and 6 if the r el a
r
h as b een
t o
pick u p at a val ue other than tap val ue,
the torq ue l eve of the r elay
b een
chan ged.
Connect the oper ating-coi l ter m in als to a source of the proper fr equency , g ood w avefor m,
and an a m pl itud e of 1 1 0 volts or higher , usin g resistan ce l oad box es for the s etting curr ent
(see the test cir cu it in Figur e 1 1 ).
® Registered Tr ademark of G en er a l E lectric Company
* Revised since l ast issue
15
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