Ch A R A Ct Er Ist Ics ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・13; Volt A Ge Allowa Ble Ra N Ge Of Coil ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・13 - Hitachi H20-T Technical Notes

Th e test s a re ca r ried out at t h e fr equ ency of oper at ions corr espondin g t o t h e cla ss of in term itt ent du t y.
F ollowin g t h e t est s of m ech a n ica l en d u r a n ce, t h e con t a ct or s h a ll st ill be ca pa ble of com p lyin g wit h t h e oper a t in g
con dit ions. Th er e sha ll be n o loosen in g of t h e par ts used for con n ect in g t h e con du ct ors.
(4) E lect r ica l endu r a nce
Wit h r espect t o it s r esist a n ce t o elect r ica l wea r , t h e con t a ct or is ch a r a ct er ized by t h e n u m ber of on -loa d oper a t in g
cycles, cor r espon din g to t h e ser vice con dit ions given in Ta ble 10 wh ich ca n be m ade wit h out r epair or r eplacemen t.
Ta ble 10. Condit ion s for m ak in g a nd br eak in g cor r espon din g t o sever a l ut ilizat ion cat egories (IE C 60947-4-1)
Ca t egor y Va lu e of t h e r at ed
oper at iona l cu rr en t
AC-1 (All valu es)
AC-2 (All valu es)
AC-3
AC-4
Ie ; Ra t ed oper a tion a l cur r ent
Ue ; Ra t ed oper a t ion a l volt a ge
I ; Cu r r en t m ade
1) Toler an ce for cosφ: ±0.05
Aft er th e t est, t h e cont a ct or sh a ll fu lfill t h e oper a tin g con dit ions a n d wit hst a nd t h e dielect ric t est volt a ges.
2-3 CH ARACTE RISTICS
2-3-1 Volt a ge Allowa ble Ran ge of Coil
Wh en t h e power -sour ce volt a ge of th e oper a tin g cir cu it t empora r ily va r ies wit hin a r a n ge of -15% t o +10% of th e
r a t ed volt a ge of coil, t h e con t a ct or oper a t es wit h ou t a ny t r ou ble. H owever , wh en t h e volt a ge con st a n t ly becom es
h igh er or lower t h a n t h e r at ed volt a ge, t he followin g fa ilu r es ma y occu r, so be su re t o use t h e cont a ct or a t t h e r at ed
volt a ge .
(1) Wh er e t h e power sou r ce volt a ge is h igher t h a n t he r a t ed volt a ge
(a ) As t h e coil becom es over hea t ed, it s life m a y be sh or ten ed a n d it m a y be bu rn t. Th e electr ical loss of t h e opera t in g
coil in crea ses in pr oport ion t o a ppr oxim at ely t h e squ are of t h e a pplied volt a ge, wh ile th e t emper a t ur e rise of t h e
coil is a ppr oxim a t ely in pr opor t ion t o t h e elect r ica l loss. Accordin gly, if t h e power sou r ce volt a ge is 110% of t h e
r a t ed volta ge of coil, t h e t em per a t ur e of coil r ises a pproxim a tely 20%. As a r esu lt , t h er e is a possibilit y t h at t h e
life of th e coil m a y be sh or t ened a n d t he coil m a y be bur n t.
(b) Th e sh ock on closin g becom es gr ea t a nd t he m echa n ica l endu r an ce is sh ort en ed, or t h e cont a ct jum ps; as a resu lt ,
t h er e is a possibilit y of incr eased con t act wea r a nd occu r r ence of weldin g. Th e h igh er t he volt a ge applied t o coil,
t h e gr eat er t h e a tt r act ion . When t h e volt a ge incr ea ses by 10%, t h e at t ra ction in cr eases by a bout 20%. Beca u se of
t h is excessively st ron g at t ra ction ,
I/Ie
1
2.5
Ie ≦ 17A
6
Ie > 17A 6
Ie ≦ 17A
6
Ie > 17A 6
U ; Volt a ge befor e m ak e
Ur ; Recover y volt a ge
Ic ; Cu rr en t br ok en
Mak e
U/Ue cosφ(1)
1 0.95
1 0.65
1 0.65
1 0.35
1 0.65
1 0.35
13
Br ea k
Ic/Ie Ur /Ue cosφ(1)
1 1
2.5 1
1 0.17
1 0.17
6 1
6 1
0.95
0.65
0.65
0.35
0.65
0.35