Hitachi H20-T Technical Notes page 7

Magnetic starters and contactors
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(2) Adver se ser vice en viron men t
(a ) H igh am bien t t emper at u r e:
Wh en t h e st a r t er a n d con t a ct or a r e u sed a t a n a m bien t t em per a t u r e h igh er t h a n t h e t em per a t u r e of t h e n or m a l
s er vice con d it ion , it is n ecess a r y t o t a k e in t o con s id er a t ion t h e r ed u ct ion of loa d cu r r en t les t t h e t em p er a t u r e
(a m bie n t t em p er a t u r e + t em p er a t u r e r is e) of t h e m old ed p a r t a n d t er m in a l e xce ed t h e m a xim u m a llowa b le
t empera t u re a nd u se of h ea t-resistin g wir e.
・ Ma xim um allowa ble t em per a t ur e
P h en ol-r esin m olded pa rt : 115℃
Ter m in a l:
(b) Low a m bien t temper at u re:
Th e t r ip p in g ch a r a ct er is t ic of t h e t h er m a l over loa d r ela y ca n n ot be gu a r a n t eed a t a t em p er a t u r e lower t h a n
-5℃ a n d t h e p er for m a n ce of s t a r t e r a n d con t a ct or is effect e d b y cold b r it t le n es s of m et a ls a n d in s u la t in g
m a t er ia ls a t su ch a t em per a t u r e. Th er efor e, it is n ecessa r y t o t a k e in t o con s ider a t ion h ea t in g by pr ovid in g t h e
in side of t he boa r d wit h a space hea ter t o ensu r e th a t t h e tem per at u r e t her e does n ot fa ll below -5℃.
H owever , wh en t h e st a r t er a n d con t a ct or a r e exp os ed t em p or a r ily t o a low t em p er a t u r e d u r in g t r a n s por t a t ion
t o a cold a r ea , even s u ch low t em p er a t u r es of -30℃ t o -40℃ a r e n o ca u se for con cer n . It is n ecess a r y, t h ou gh ,
t o t a k e m ea su r es a ga in st defor m a t ion du e t o r ever se ben din g of bim et a ls a n d br it t len ess of in su la t in g m a t er ia ls,
t h u s wh en pla cin g a n order, please inform u s if t r a nspor t at ion t o a cold a r ea is in volved.
(c) H igh h u midit y:
In ca se of h igh h u m id it y, t h er e is t h e da n ger of lower in g of in su la t ion a n d decr ea se of t h e elect r ica l en du r a n ce,
et c. Accor din gly, it is n ecessa r y t o a dopt a n a ppr opr ia t e pr ot ect ive st r u ct u r e a n d per for m su fficien t m a in t en a n ce
a n d in spect ion.
(d) Adverse a tm osph er e:
If t h e st a r t er a n d con t a ct or a r e u sed in a n a t m os p h er e con t a in in g m u ch d u s t , cor r os ive ga s , com bu s t ible ga s,
s a lt , et c., it is n eces s a r y t o p r ovide a p r ot ect ive s t r u ct u r e wh ich is d u s t -pr oof, cor r os ion -pr oof, exp los ion -pr oof,
et c.
(e) P laces wh er e vibr at ion a n d sh ock a r e gr ea t:
Th e st a r t er a n d con t a ct or s h ou ld n ot be in st a lled d ir ect ly t o a m a ch in e, equ ipm en t , et c. pr od u cin g p a r t icu la r ly
gr ea t vibr a t ion a n d sh ock . If it is u n a void a ble t o in st a ll in su ch a con dit ion , a vibr a t ion isola t in g d evice sh ou ld
be pr ovided.
105℃
3

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