POLARIZED, MONOSTABLE
SAFETY RELAY
SF RELAYS
Double contact
FEATURES
53.3±0.5
2.098±.020
25.0
.984
16.5±0.5
.650±.020
2 Form A 2 Form B
53.3±0.5
2.098±.020
33±0.5
1.299±.020
16.5±0.5
.650±.020
4 Form A 4 Form B
mm inch
• High contact reliability
High contact reliability is achieved through
the use of a double contact.
• Forced operation contacts
(2 Form A 2 Form B)
N.O. and N.C. side contacts are
connected through a card so that one
interacts with the other in movement. In
case of a contact welding, the other keeps
a min. 0.5mm .020inch contact gap.
• Independent operation contacts
(4 Form A 4 Form B)
There are 4 points of forced operation
contacts.
Each pair of contacts is free from the main
armature and is independent from each
other. So if a N.O. pair of contacts are
welded, the other 3 N.O. contacts are not
effected (operate properly) That enables
to plan a circuit to detect welding or go
back to the beginning condition.
• Separated chamber structure (2 Form
A 2 Form B, 4 Form A 4 Form B)
N.O. and N.C. side contacts are put in
each own space surrounded with a card
and a body-separater. That prevents short
circuit between contacts, which is caused
by their springs welding or damaged.
• High breakdown voltage 2,500 Vrms
between contacts and coil
• High sensitivity
Realizes thin shape and high sensitivity
(500 mW nominal operating power) by
utilizing high-efficiency polarized
magnetic circuit with 4-gap balanced
armature.
• Complies with safety standards
Standard products are UL, CSA, TÜV and
SEV certified. Comform to European
standards. TÜV certified (945/EL, 178/
88). Complies with SUVA European
standard.
SPECIFICATIONS
Contact
Characteristics (at 20°C 68°F)
Contact arrangement
Initial contact resistance, max.
(By voltage drop 6 V DC 1 A)
Contact material
Rating
(resistive)
Expected
life (min.
operations)
Nominal switching
capacity
Max. switching power
Max. switching voltage
Max. carrying current
Mechanical (at 180 cpm)
Electrical (at 20 cpm)
2 Form A
2 Form B
4 Form A
4 Form B
30 mΩ
Gold-flashed silver alloy
6 A 250 V AC, 6 A 30 V DC
1,500 VA, 180 W
440 V AC, 30 V DC
6A
107
105
Coil
Nominal operating power
Contact arrangement
Max. operating speed
Initial insulation resistance*1
Between open contacts
Initial
breakdown Between contact sets
voltage*2
Between contact and coil
Operate time*3 (at nominal voltage)
Release time (without diode)*3
(at nominal voltage)
Temperature rise (at nominal voltage)
(at 20°C)
Shock resistance
500 mW
Remarks
* Specifications will vary with foreign standards certification ratings.
*1 Measurement at same location as “Initial breakdown voltage” section
*2 Detection current: 10mA
*3 Excluding contact bounce time
*4 Half-wave pulse of sine wave: 11ms; detection time: 10µs
*5 Half-wave pulse of sine wave: 6ms
*6 Detection time: 10µs
*7 Refer to 6. Conditions for operation, transport and storage mentioned in
AMBIENT ENVIRONMENT.
Functional*4
Destructive*5
Functional*6
Vibration resistance
Destructive
Conditions for operation,
Ambient
transport and storage*7 (Not temp.
freezing and condensing at
Humidity
low temperature)
Unit weight
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
2 Form A
4 Form A
2 Form B
4 Form B
180 cpm (at nominal voltage)
Min. 1,000 MΩ at 500 V DC
1,300 Vrms
2,500 Vrms
2,500 Vrms
Max. 30 ms
Max. 15 ms
Max. 45°C
with nominal coil voltage and
at 6 A carry current
Min. 294 m/s2 {30 G}
Min. 980 m/s2 {100 G}
10 to 55 Hz at double
amplitude of 2 mm
10 to 55 Hz at double
amplitude of 2 mm
–40°C to +70°C
–40°F to +158°F
5 to 85% R.H.
Approx.
38 g 1.34 oz
Approx.
47 g 1.66 oz
SF Double contact
ORDERING INFORMATION
Ex. SF
2
D
TYPICAL APPLICATIONS
• Industrial equipment such as presses and machine tools
DC 5 V
Contact arrangement
Coil voltage
2: 2 Form A 2 Form B
4: 4 Form A 4 Form B
DC 5, 12, 24, 48, 60 V
UL/CSA, TÜV, SEV approved type is standard
TYPES AND COIL DATA (at 20°C 68°F)
Contact
arrangement
2 Form A
2 Form B
4 Form A
4 Form B
Part No.
Nominal
voltage, V DC
Pick-up
voltage, VDC
(max.)
Drop-out
voltage, V DC
(min.)
Coil resistance
Ω (±10%)
SF2D-DC5V
SF2D-DC12V
SF2D-DC24V
SF2D-DC48V
SF2D-DC60V
SF4D-DC5V
SF4D-DC12V
SF4D-DC24V
SF4D-DC48V
5
12
24
48
60
5
12
24
48
3.75
9
18
36
45
3.75
9
18
36
0.5
1.2
2.4
4.8
6.0
0.75
1.8
3.6
7.2
50
288
1.152
4.608
7.200
50
288
1.152
4.608
Nominal
operating
current,
mA (±10%)
100
41.7
20.8
10.4
8.3
100
41.7
20.8
10.4
SF4D-DC60V
60
45
9.0
7.200
8.3
Nominal
operating
power, mW
Max. allowable
voltage, V DC
500
500
500
500
500
500
500
500
500
6
14.4
28.8
57.6
72
6
14.4
28.8
57.6
500
72
DIMENSIONS
mm inch
Schematic (Bottom view)
1. 2 Form A 2 Form B
5
6
7
8
9
10
11
12
1
16±0.5
.630±.020
2
0.5
.020
1.0
.039
12.7
.500
5.08
.200
12.7
.500
3.0±0.5
.118±.020
12.7
.500
53.3±0.5
2.098±.020
0.30
.012
25.0
.984
5
6
7
PC board pattern (Bottom view)
0.48
.019
8
2.54
.100
10-1.4 DIA. HOLES
10-.055 DIA. HOLES
2.54
.100
1
12.7
.500
7.62
.300
2
9
10
11
12
General tolerance: ±0.3 ±.012
Tolerance: ±0.1 ±.004
2. 4 Form A 4 Form B
Schematic (Bottom view)
16±0.5
.630±.020
1.0
.039
12.7
.500
12.7
.500
12.7
.500
14
15
16
5
9
6
10
7
11
8
12
17
18
19
20
1
0.5
.020
5.08
.200
13
2
3.0±0.5
.118±.020
53.3±0.5
2.098±.020
0.48
.019
PC board pattern (Bottom view)
33±0.5
299±.020
13
5
0.30
.012
14
6
15
7
16
8
7.62
.300
1
0.48 12.7
.019 .500
7.62
.300
2
9
17
10
18
11
19
12
20
2.54
.100
18-1.4 DIA. HOLES
18-.055 DIA. HOLES
2.54
.100
7.62
.300
General tolerance: ±0.3 ±.012
Tolerance: ±0.1 ±.004
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
SF Double contact
REFERENCE DATA
2. Temperature rise
3. Ambient temperature characteristics
Tested sample: SF4D-DC24V
Quantity: n = 6
Coil applied voltage: 100%V, 120%V
Contact carry current: 6A
Tested sample: SF4D-DC12V
Quantity: n = 6
30
Temperature rise, °C
Operate/release time, ms
50
40
30
Operate time
20
Release time
10
0
Rate of
change, %
1. Operate/release time (without diode)
Tested sample: SF2D-DC24V
Quantity: n = 20
70
80
Max.
x
Min.
Max.
x
Min.
25
Inside the coil
100
50
Drop-out voltage
20
-40 -20
15
Pick-up voltage
0
20 40
10
Contact
60 80
Ambient
temperature, °C
-50
5
0
90
100
110
120 130
Coil applied voltage, %V
100
-100
110
120
Coil applied voltage, %V
SAFETY STRUCTURE OF SF RELAYS
This SF relay design ensures that
subsequent operations shut down and can
automatically return to a safe state when
the SF relay suffers overloading and other
circuit abnormalities (unforeseen
externally caused circuit or device
breakdowns, end of life incidents, and
noise, surge, and environmental
influences) owing to contact welding,
spring fusion or, in the worst-case
scenario, relay breakdown (coil rupture,
faulty operation, faulty return, and fatigue
and breakage of the operating spring and
return spring), and even in the event of
end of life.
Structure
Operation
Min. 0.5 mm .020 inch
Contact a
1. Forced operation method
(2a2b, 4a4b types)
Card
Contact b
Weld
The two contacts “a” and “b” are coupled with the same
card. The operation of each contact is regulated by the
movement of the other contact.
Even when one contact is welded closed,
the other maintains a gap of greater than
0.5 mm .020 inch.
In the diagram on the left, the lower
contact "b" have welded but the upper contact "a" maintain at a gap of greater than
0.5 mm .020 inch.
Subsequent contact movement is
suspended and the weld can be detected
External NO
contact weld
Return
Enables design of safety circuits that allow
weld detection and return at an early stage.
2. Independent operation method
(4a4b type)
Return
Return
None of four contacts are held in position by the armature.
Even though one of the external N.O. contacts has
welded, the other three contacts have returned owing to
the de-energizing of the coil.
In independent chambers, the contacts "a" and "b" are
kept apart by a body/card separator or by the card itself.
Case separator
1
Prevents shorting and fusing of springs and
spring failure owing to short-circuit current.
Card
3. Separate chamber method
(2a2b, 4a4b types)
Contact a
2
Body
separator
Contact b
4. 2a2b contact
4a4b contact
As shown at the top right of the diagram on
the left, if the external N.O. contact welds, a
0.5 mm .020 inch gap is maintained.
Each of the other contacts returns to N.O.
because the coil is no longer energized.
Structure with independent COM contact of (2a2b),
(3a1b), (4a4b) contacts.
As shown on the diagram on the left, even
if the operating springs numbered 1 and 2
there is no shorting between "a" and "b"
contacts.
Independent COM enables differing pole
circuit configurations. This makes it
possible to design various kinds of control
circuits and safety circuits.
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
SF Double contact
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.
Internal 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,
No. 5 and No. 7) are maintained at 0.5 mm .020inch or greater. Reliable cut-off is thus ensured.
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,
No. 4, No. 6 and No. 8) are maintained at 0.5 mm .020inch or greater. Reliable cut-off is thus ensured.
No.8
No.1
No.8
No.1
No.7
No.2
No.7
No.2
No.6
No.3
No.6
No.3
No.5
No.4
No.5
No.4
Non-energized
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 inch.
Energized (when no. 2 contact is welded)
External Contacts Weld
a) When external contacts (No. 4 or No. 8) are welded, gaps of 0.5 mm .020inch and greater are maintained between adjacent contacts
and other contacts operate normally by the coil being energized.
b) When external contacts (No. 1 or No. 5) are welded, gaps of 0.5 mm .020inch and greater are maintained between adjacent contacts
and other contacts are released by the coil being de-energized.
No.8
No.1
No.8
No.1
No.7
No.2
No.7
No.2
No.6
No.3
No.6
No.3
No.5
No.4
No.5
No.4
Energized
Non-energized (when no. 1 contact is welded)
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 .020 inch.
If the No. 1 contact welds.
The adjacent No. 2 contact maintains a gap of
greater than 0.5 mm .020 inch. The other
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 .020 inch;
each of the form “b” contacts (No. 4, 6, and 8)
return to a closed state.
Weld
Energized
Contact gap
min 0.5 mm .020 inch
Non-energized
Contact Operation Table
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.
No.8
No.1
No.7
No.2
No.6
No.3
No.5
No.4
Contact No. No.1 No.2 No.3 No.4 No.5 No.6 No.7 No.8
Terminal No. 20–19 12–11 8–7 16–15 13–14 5–6 9–10 17–18
Contact No.
Contact No.
1
1
2
>0.5
3
Welded
4
≠
contact
5
>0.5
No.
6
>0.5
7
8
≠
2
>0.5
>0.5
>0.5
≠
>0.5
>0.5
State of other contacts
3
4
5
6
>0.5
≠
>0.5
≠
>0.5
>0.5
>0.5
>0.5
>0.5
≠
>0.5
>0.5
≠
>0.5
>0.5
>0.5
>0.5
>0.5
≠
>0.5
≠
>0.5
7
>0.5
>0.5
≠
>0.5
>0.5
8
≠
>0.5
>0.5
≠
>0.5: contact gap
is kept at min. 0.5
mm .020 inch
≠: contact closed
Empty cells: either
closed or open
>0.5
>0.5
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.
For Cautions for Use, see Relay Technical Information.
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
