Westinghouse DK-15, Manual

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Type DK- 1 5 and DK-25 Air Circuit Breaker
Genera]
The DK air circuit breake r , c omple te with a l l attachment s , i s a
self-c ontained unit , and haa been mounted , ad jus ted and calibrated on i t a
own permanent pane l a t the fa c tory . I t i s de s igned only to b e mounted in a
vertical po si tion, and a l l inspe c tions for proper opera t ion mu s t be made
with the breaker main pane l held ve rt ically .
Unpacking
C are mu s t be exerci sed when unpacking to make sure that no part s
are broken or damaged , and an inspe c t ion s hould be made immed ia t e ly to
che c k for any damage in transit . A l l dus t and d irt should be carefully
blown out of the comp le te a s sembly, e spe c ially in the c l o s ing t oggle link­
age ove rload attachment s and such o ther attachme nt s a s are supplied .
I t i s not adv isable to lubrica te any par t s of the breake r . The
lubrica tion supp lied during fac tory a s sembly , whe re nec e s sary , is a spe c ia l
form o f gre a se which i s u sed sparing ly . Thi s wi l l b e found suffic ient for
years of s e rvice . Add it iona l oil wi l l only promote the ac cumulation of dus t
and d ir t .
I n new ins talla ti ons , the breake r mu s t be carefu l ly pro tec ted
from pla s te r , c onc rete and o the r fore ign gritty partic l e s tha t may add
fric tion to the moving part s
in
the toggle linkage .
Inspection
F ina l ins pe c tion should preferably be made with the breaker in
its pe rmanent mount ing , but if this is impo s s ible , it can be set up r igid ly
in a ve rtical pos ition whil e the inspe c tion i s made .
Rotate the manual operating handle s l owly in a c l oc kwise dire c ­
tion t o move the conta c t s toward the c l o sed po s i tion . C he c k the movement
of each arc t ip through the throat of the 11De - ion11 arc interrupting chamber
t o make sure that the tips d o not rub again s t the c e ramic s id e plate s .
C ontinue the c l o s ing motion until the moving arc tips j us t touch the sta­
t ionary arc tip s . Che ck the main contac t se para tion a t approximate ly
1/8
inch, a s shown on F ig s .
2
and
3 .
C ontinue the hand le rotation to the fully
c lo sed po s ition and watch the main c ontac t over travel as evidenced by rotary
motion away from i t s s to p , ad jacent to the s e c ti on whe re the shunt i s
attached .
Re turn the manua l ly operated handle to the neutral position and
r otate counte rc lo ckwis e t o trip the breake r . The toggle linkage should
c ol lap se and the moving c onta c t a s sembly move fre e ly to the ful l open posi­
tion .
This i s followed immediately by c ompl e te r e s e tting of the links in
the toggle me chanism . This rese tting operation is ac complished entirely by
gravity . For this rea son the l inks mus t always be free to move without
fr�ction or binding .
Adjustment of Contacts
The arc t ip ad jus tment
should be made as shown in Figs .
2
and
3 .
There i s no ad justment provided for the main c ontac t s , and und er ord inary
c ircums tanc e s the se main conta c t s will la s t the life of the breaker without
repair other than occas iona l c leaning . Both main and arc ing contac t s are a
high s i lver alloy .
Replacement of Contacts
The sub - pane l , barr i er and "De - i on " interrupting a s s emb ly may be
r emoved a s a un i t by taking out two bol t s at the outer end s of the sub - panel .
Thi s gives a c c e s s to the conta c t s for easy inspect i on or replacement .
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