Lat Ch Ed Con T Act Or - Hitachi H20-T Technical Notes

2-1-3 Lat ch ed Con t act or

F ig. 8 Open con dit ion
La t ch ed con t a ct or h a s two coils, on e is for closin g a n d t h e ot h er is for r elea sin g. Th e st r u ct u r e of t h e la t ch ed con-
t a ct or is sh own in F ig. 8 a n d F ig. 9. Wh en t h e closin g coil is excit ed, t h e m ovin g cor e is a tt r a ct ed t o t h e fixed core
s o t h a t it m oves in t h e a r r ow A dir ect ion , a n d t h e m ovin g con t a ct lin k ed t o t h e m ovin g cor e com es in t o con t a ct
with t he fixed con ta ct, t h en closes t he cir cu it . At th e sam e t ime, t h e r od link ed to t he m ovin g cor e m oves in t he same
d ir ect ion a s t h e m ovin g cor e a n d t h e con ca ve of t h e r od m oves t o poin t （a ), t h en t h e m ovin g cor e of t h e r elea se
elect r om a gn et m oves in t h e ar r ow B dir ect ion so a s t o en ga ge wit h t h e con ca ve pa rt . In t h is st at e, t h e m ovin g cor e
of t h e closin g elect r om a gn et is m ech a n ica lly h eld so th a t even wh en r eset t in g t h e excit a t ion of t h e closin g coil, t h e
con t act or is st ill in closed condit ion .
Wh en t h e r elea sin g coil is excit ed, t h e m ovin g cor e of r elea se electr om a gn et is a t t r a cted t o t h e fixed cor e so t h a t it
m oves in th e direction of t he ar r ow D sh own in Fig. 9, a n d t he m ovin g cor e disen ga ges fr om t h e con ca ve of th e rod.
Th en , t h e m ovin g cor e of clos in g elect r om a gn et m oves in t h e dir ect ion of t h e a r r ow C by t h e for ce of t h e r et u r n
s p r in g, a n d t h e m ovin g con t a ct lin k ed t o t h e m ovin g cor e s ep a r a t es fr om t h e fixed con t a ct , a n d s im u lt a n eou s ly
t h e circu it opens. Th e oper at in g circu it is sh own in F ig. 10.
F ig. 10 Oper at in g circu it
(Not e) ON a nd OF F cont a ct s sh ou ld be int erlock ed.
Rem a rks: CC: Closin g coil
TC: Relea sin g coil (Tr ippin g coil)
(E xpla n at ion)
ON : Clos in g b y m ea n s of excit a t ion of CC, wh ich ca n be h eld m e-
ch a n i ca l l y. Aft e r clos i n g, con t a ct N O i s i n "O N " s t a t e , a n d
con t act NC is in "OF F " st at e.
OF F : Relea s in g by m ea n s of excit a t ion of TC. Aft er r elea se, con t a ct
N O r e t u r n s t o "O F F " a n d co n t a c t N C , t o "O N ". C on t a ct s
N O a n d N C a r e bu ilt in . T h e e xp la n a t or y figu r e s h ows a ca s e
w h e r e t h e p owe r s ou r ces of ON a n d O F F a r e t h e s a m e . H ow-
e ve r , e ve n if t h e y a r e d iffe r e n t , t h e s a m e O N /O F F op e r a t ion
is possible.
8
Fig. 9 Closed condition