SF4D-DC48V PANASONIC EW, SF4D-DC48V Datasheet - Page 4

• Manufacturer Part Number: SF4D-DC48V
• Description: SF4D (4a4b)
• Manufacturer: PANASONIC EW

THE OPERATION OF SF RELAYS (when contacts are welded)
SF relays work to maintain a normal operating state even when the contact welding occur by overloading or short-circuit
currents. It is easy to make weld detection circuits and safety circuits in the design to ensure safety even if contacts weld.
a) When internal contacts (No. 2 or No. 6) are welded, the armature becomes non-operational and the four contact gaps (No. 1, No. 3,
b) When internal contacts (No. 3 or No. 7) are welded, the armature becomes non-operational and the four b type contact gaps (No. 2,
a) When external contacts (No. 4 or No. 8) are welded, gaps of 0.5 mm
b) When external contacts (No. 1 or No. 5) are welded, gaps of 0.5 mm
The table below shows the state of the other contacts. In case of form “a” contact weld the coil applied voltage is 0 V.
In case of form “b” contact weld the coil applied voltage is nominal.
For Cautions for Use, see Relay Technical Information.
If external connections are made in series.
Even if one of the contacts welds, the other contacts
operate independently and the contact gaps are
maintained at greater than 0.5 mm
No.8
No.6
No.8
No.6
No.8
No.6
No. 5 and No. 7) are maintained at 0.5 mm
No. 4, No. 6 and No. 8) are maintained at 0.5 mm
No.7
No.5
and other contacts operate normally by the coil being energized.
and other contacts are released by the coil being de-energized.
No.7
No.5
No.7
No.5
Terminal No. 20–19 12–11 8–7 16–15
Contact No.
Contact Operation Table
External Contacts Weld
Internal Contacts Weld
No.1 No.2 No.3 No.4
Non-energized
Energized
13–14 5–6 9–10 17–18
No.5 No.6 No.7 No.8
.020
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No.1
No.3
No.1
No.3
No.1
No.3
No.2
No.4
No.2
No.4
No.2
No.4
inch.
.020inch
Note: Contact gaps are shown at the initial state.
If the contact transfer is caused by load switching, it is necessary to check the actual loading.
Contact No.
Welded
contact
Non-energized
No.8
No.7
No.6
No.5
No.8
No.7
No.6
No.5
No.
Non-energized (when no. 1 contact is welded)
.020inch
Energized (when no. 2 contact is welded)
Energized
Contact No.
or greater. Reliable cut-off is thus ensured.
or greater. Reliable cut-off is thus ensured.
1
2
3
4
5
6
7
8
>0.5
>0.5
>0.5
1
≠
≠
.020inch
.020inch
Weld
>0.5 >0.5
>0.5
>0.5 >0.5
>0.5
>0.5
2
≠
and greater are maintained between adjacent contacts
and greater are maintained between adjacent contacts
>0.5
>0.5
>0.5
State of other contacts
3
≠
No.1
No.2
No.3
No.4
No.1
No.2
No.3
No.4
>0.5
>0.5
>0.5
4
≠
≠
Contact gap
min 0.5 mm
>0.5
>0.5
>0.5
If the No. 2 contact welds.
Each of the four form “a” contacts (No. 1, 3, 5,
and 7) maintains a gap of greater than 0.5 mm
.020
If the No. 1 contact welds.
The adjacent No. 2 contact maintains a gap of
greater than 0.5 mm
contacts, because the coil is not energized,
return to their normal return state; each of
form “a” contacts (No. 3, 5, and 7) maintains a
contact gap of greater than 0.5 mm
each of the form “b” contacts (No. 4, 6, and 8)
return to a closed state.
5
≠
≠
.020 inch
inch.
>0.5
>0.5
>0.5 >0.5
>0.5
>0.5 >0.5
6
≠
>0.5
>0.5
>0.5
7
≠
SF
>0.5
>0.5
>0.5
.020
8
≠
≠
Double contact
inch. The other
>0.5: contact gap
is kept at min. 0.5
mm
≠ : contact closed
Empty cells: either
closed or open
.020 inch
.020
inch;