Applica T Ion A N D Select Ion ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・18; Applica T Ion Of Ac3 ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・18 - Hitachi H20-T Technical Notes

2-4 AP P LICATION AND SE LE CTION
Th e con t act or s sh ou ld be select ed a ccor din g t o t h e t ypes of t h eir loads. Th e loads a re classified in IE C60947 as shown
in t he followin g t a ble, a n d in clu de th ose of t h e tr a nsfor mer, con den ser, et c. in ot h er ca t egor y. Ta ble 13 pr ovides
r efer en ces for t h e select ion of cont a ct ors.
Ca t egor y
IE C
60947-4-1
2-4-1 Applica t ion of AC3
(1) St a n dar d for select ion
Wh en con tr ollin g t h e m ot or by t h e con t act or , t h e loa d cu rren t sh own in F ig. 16 flows, so a cont a ct or cor r espon din g
t o t h is cu r ren t is select ed. Th e k ey poin ts of t h e select ion ar e given in Ta ble 14 accor din g t o th e m a in it em s.
Ta ble 13. Refer ence for selection
Typica l a pplica t ion s
AC1 Non -in duct ive or sligh tly indu ct ive
loa d, r esist a n ce fu r n aces
AC2 Slip-r in g m ot or s :
St a rt in g , plu ggin g
AC3 Squ irr el-ca ge mot or s :
St a rt in g, swit ch in g off m otors
du r in g r u n n in g
AC4 Squ irr el-ca ge mot or s:
St a rt in g, plu ggin g, in ch in g
DC loa d
St a r-delt a st a rt er
Con denser loa d
Open in g/closin g of pr im a r y side of
t r a nsfor mer
F ig. 16 Motor cu rr en t
Refer to 2-4-3.
Th e sa me as par a gr aph 24-l
u n less plu ggin g is included.
Refer to 2-4-1.
Refer to 2-4-2.
Refer to 2-4-4.
Refer to 2-4-5.
Refer to 2-4-6.
Refer to 2-4-7.
18
Select ion