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D4B-
N
D4B-
N
7
Operation
POSITIVE CONTACT OPENING MECHANISM
1NO/1NC Contact (Snap-action)
If metal deposition between mating contacts occurs on the NC contact side, they can be pulled apart by the shearing force and tensile force
generated when part B of the safety cam or plunger engages part A of the movable contact blade. When the safety cam or plunger is moved in
the direction of the arrow, the Limit Switch releases.
1. When metal deposition occurs.
2. When contacts are being pulled apart.
3. When contacts are completely
pulled apart.
Movable contact
blade
Movable contact
Plunger
Safety cam
Fixed contact (NC)
Safety cam directly
pushes up the
movable contact
blade.
A
B
1NC/1NO Contact (Slow-action)
Conforms to IEC 947-5-1 Positive Opening
When metal deposition occurs, the contacts
are separated from each other by the plunger
being pushed in.
Contact spring
Return spring
Fixed contact (NC)
Movable contact
Plunger
2NC Contact (Slow-action)
Conforms to EN60947-5-1
When metal deposition occurs, the contacts
are separated from each other by the plunger
being pushed in.
is marked on the product to indicate ap-
proval of positive opening.
Contact spring
Return spring
Fixed contact (NC)
Movable contact
Plunger
Contact Form (EN50013)
Model
1NC/1NO
Contacts
(Snap-action)
Contact
Diagrams (See Note.)
13
11
14
12
Only 11 to 12 contacts are
positive opening.
EN60947-5-1 conformity
Za
11 to 12
13 to 14
0
2 mm max.
(7 mm)
1NC/1NO
Contacts
(Slow-action)
11
12
23
24
Only 11 to 12 contacts are
positive opening.
EN60947-5-1 conformity
Zb
11 to 12
23 to 24
0
2 mm max.
(7 mm)
(3 mm)
2NC Contacts
(Slow-action)
11
21
12
22
Both 11 to 12 and 21 to 22
contacts are positive opening.
EN60947-5-1 conformity
Zb
11 to 12
21 to 22
0
2 mm max.
(7 mm)
Note: 1. Contact operation
Closed
Open
2. The stroke value in parentheses refers to the D4B-
70N.