SF RELAYS
Double contact
POLARIZED, MONOSTABLE
SAFETY RELAY
mm inch
25.0
.984
2 Form A 2 Form B
4 Form A 4 Form B
16.5±0.5
.650±.020
53.3±0.5
2.098±.020
33±0.5
1.299±.020
16.5±0.5
.650±.020
53.3±0.5
2.098±.020
FEATURES
• 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
Coil
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: 10
µ
s
*
5
Half-wave pulse of sine wave: 6ms
*
6
Detection time: 10
µ
s
*
7
Refer to 6. Conditions for operation, transport and storage mentioned in
AMBIENT ENVIRONMENT.
Characteristics (at 20°C 68°F)
Contact arrangement 2 Form A
2 Form B 4 Form A
4 Form B
Initial contact resistance, max.
(By voltage drop 6 V DC 1 A) 30 m
Ω
Contact material Gold-flashed silver alloy
Rating
(resistive)
Nominal switching
capacity 6 A 250 V AC, 6 A 30 V DC
Max. switching power 1,500 VA, 180 W
Max. switching voltage 440 V AC, 30 V DC
Max. carrying current 6 A
Expected
life (min.
operations)
Mechanical (at 180 cpm) 10
7
Electrical (at 20 cpm) 10
5
Nominal operating power 500 mW
Contact arrangement 2 Form A
2 Form B 4 Form A
4 Form B
Max. operating speed 180 cpm (at nominal voltage)
Initial insulation resistance*
1
Min. 1,000 M
Ω
at 500 V DC
Initial
breakdown
voltage*
2
Between open contacts 1,300 Vrms
Between contact sets 2,500 Vrms
Between contact and coil 2,500 Vrms
Operate time*
3
(at nominal voltage) Max. 30 ms
Release time (without diode)*
3
(at nominal voltage) Max. 15 ms
Temperature rise (at nominal voltage)
(at 20°C)
Max. 45°C
with nominal coil voltage and
at 6 A carry current
Shock resistance Functional*
4
Min. 294 m/s
2
{30 G}
Destructive*
5
Min. 980 m/s
2
{100 G}
Vibration resistance
Functional*
6
10 to 55 Hz at double
amplitude of 2 mm
Destructive 10 to 55 Hz at double
amplitude of 2 mm
Conditions for operation,
transport and storage*
7
(Not
freezing and condensing at
low temperature)
Ambient
temp. –40°C to +70°C
–40°F to +158°F
Humidity 5 to 85% R.H.
Unit weight Approx.
38 g 1.34 oz Approx.
47 g 1.66 oz
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
SF
Double contact
TYPES AND COIL DATA (at 20°C 68°F)
mm inch
DIMENSIONS
1. 2 Form A 2 Form B
Contact
arrangement Part No. Nominal
voltage, V DC
Pick-up
voltage, VDC
(max.)
Drop-out
voltage, V DC
(min.)
Coil resistance
Ω
(±10%)
Nominal
operating
current,
mA (±10%)
Nominal
operating
power, mW
Max. allowable
voltage, V DC
2 Form A
2 Form B
SF2D-DC5V 5 3.75 0.5 50 100 500 6
SF2D-DC12V 12 9 1.2 288 41.7 500 14.4
SF2D-DC24V 24 18 2.4 1.152 20.8 500 28.8
SF2D-DC48V 48 36 4.8 4.608 10.4 500 57.6
SF2D-DC60V 60 45 6.0 7.200 8.3 500 72
4 Form A
4 Form B
SF4D-DC5V 5 3.75 0.75 50 100 500 6
SF4D-DC12V 12 9 1.8 288 41.7 500 14.4
SF4D-DC24V 24 18 3.6 1.152 20.8 500 28.8
SF4D-DC48V 48 36 7.2 4.608 10.4 500 57.6
SF4D-DC60V 60 45 9.0 7.200 8.3 500 72
General tolerance: ±0.3 ±.012
12.7
.500
53.3±0.5
2.098±.020
12.7
.500
12.7
.500
5.08
.200
6587
109
1
2
1211
16±0.5
.630±.020
12.7
.500
3.0±0.5
.118±.020
0.5
.020
0.48
.019
25.0
.984
7.62
.300
1.0
.039
0.30
.012
Schematic (Bottom view)
PC board pattern (Bottom view)
Tolerance: ±0.1 ±.004
5
1
2
678
9 101112
2.54
.100
2.54
.100
10-1.4 DIA. HOLES
10-.055 DIA. HOLES
2. 4 Form A 4 Form B
General tolerance: ±0.3 ±.012
12.7
.500
53.3±0.5
2.098±.020
12.7
.500
12.7
.500
5.08
.200
65
1817 2019
87
109
1413 1615
1
2
1211
16±0.5
.630±.020
12.7
.500
7.62
.300
7.62
.300
3.0±0.5
.118±.020
0.5
.020
3
3±0.5
2
99±.020
7.62
.300
1.0
.039
0.48
.019
0.48
.019
0.30
.012
Schematic (Bottom view)
PC board pattern (Bottom view)
Tolerance: ±0.1 ±.004
1
13
5
2
14
6
15
7
16
8
9
17
10
18
11
19
12
20
2.54
.100
2.54
.100
18-1.4 DIA. HOLES
18-.055 DIA. HOLES
ORDERING INFORMATION
Ex. SF 2 D DC 5 V
Contact arrangement Coil voltage
DC 5, 12, 24, 48, 60 V2: 2 Form A 2 Form B
4: 4 Form A 4 Form B
UL/CSA, TÜV, SEV approved type is standard
TYPICAL APPLICATIONS
• Industrial equipment such as presses and machine tools
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
SF
Double contact
REFERENCE DATA
1. Operate/release time (without diode)
Tested sample: SF2D-DC24V
Quantity: n = 20
2. Temperature rise
Tested sample: SF4D-DC24V
Quantity: n = 6
Coil applied voltage: 100%V, 120%V
Contact carry current: 6A
3. Ambient temperature characteristics
Tested sample: SF4D-DC12V
Quantity: n = 6
10
20
30
0
40
50
8070 10090 120 130110
Coil applied voltage, %V
Operate/release time, ms
Operate time
Release time
Min.
Max.
x
Min.
Max.
x
5
10
15
0
20
25
30
120100 110
Coil applied voltage, %V
Inside the coil
Contact
Temperature rise, °C
-40 -20 0
20 40 60 80
-50
100
50
-100
Drop-out voltage
Pick-up voltage
Ambient
temperature, °C
Rate of
change, %
Structure Operation
1. Forced operation method
(2a2b, 4a4b types)
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 con-
tact "a" maintain at a gap of greater than
0.5 mm .020 inch.
Subsequent contact movement is
suspended and the weld can be detected
2. Independent operation method
(4a4b type)
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.
Enables design of safety circuits that allow
weld detection and return at an early stage.
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.
3. Separate chamber method
(2a2b, 4a4b types)
In independent chambers, the contacts "a" and "b" are
kept apart by a body/card separator or by the card itself.
Prevents shorting and fusing of springs and
spring failure owing to short-circuit current.
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.
4. 2a2b contact
4a4b contact Structure with independent COM contact of (2a2b),
(3a1b), (4a4b) contacts.
Independent COM enables differing pole
circuit configurations. This makes it
possible to design various kinds of control
circuits and safety circuits.
Min. 0.5 mm .020 inch
Contact a
Card
Weld
Contact b
Return
Return
External NO
contact weld
Return
Case separator Card
Contact a
Body
separator
Contact b
1
2
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.
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.
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.
Internal Contacts Weld
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.
No.1
No.2
No.3
No.4
No.8
No.7
No.6
No.5
Non-energized
No.1
No.2
No.3
No.4
No.8
No.7
No.6
No.5
Energized (when no. 2 contact is welded)
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.
External Contacts Weld
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.
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.
No.1
No.2
No.3
No.4
No.8
No.7
No.6
No.5
Energized
No.1
No.2
No.3
No.4
No.8
No.7
No.6
No.5
Non-energized (when no. 1 contact is welded)
Energized
Contact gap
min 0.5 mm .020 inch
Weld
Non-energized
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.
Contact Operation Table
No.1
No.2
No.3
No.4
No.8
No.7
No.6
No.5
Contact No. No.1 No.2 No.3 No.4
Terminal No.
20–19 12–11 8–716–15
No.5 No.6 No.7 No.8
13–14 5–69–10 17–18
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. State of other contacts
>0.5: contact gap
is kept at min. 0.5
mm .020 inch
≠
: contact closed
Empty cells: either
closed or open
Contact No. 12345678
Welded
contact
No.
1 >0.5 >0.5
≠
>0.5
≠
>0.5
≠
2 >0.5 >0.5 >0.5 >0.5
3 >0.5 >0.5 >0.5 >0.5
4
≠
>0.5 >0.5
≠
>0.5
≠
>0.5
5 >0.5
≠
>0.5
≠
>0.5 >0.5
≠
6 >0.5 >0.5 >0.5 >0.5
7 >0.5 >0.5 >0.5 >0.5
8
≠
>0.5
≠
>0.5
≠
>0.5 >0.5
For Cautions for Use, see Relay Technical Information.
All Rights Reserved © COPYRIGHT Matsushita Electric Works, Ltd.
