SF
(SF3 pending) (SF3 pending)
POLARISED, MONOSTABLE
SAFETY RELAY with
(mechanical linked) forced
contacts operation
π
• Forced operation contacts (2 Form A
2 Form B, 3 Form A 1 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)
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
16.5±0.3
.650±.012
25.0
.984
53.3±0.3
2.098±.012
16.5±0.3
.650±.012
33±0.3
1.299±.012
53.3±0.3
2.098±.012
SF-RELAYS
FEATURES
25.0
.984
53.3±0.3
2.098±.012
16.5±0.3
.650±.012
mm inch
(SF3 pending)
enables to plan a circuit to detect welding
or go back to the beginning condition.
• Separated chamber structure
(2 Form A 2 Form B, 3 Form A 1 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.
• UL/CSA, TÜV, SEV approved
(UL/CSA, SEV of SF3 pending)
SPECIFICATIONS
Contact
Characteristics (at 25°C 77°F, 50% Relative humidity)
Type
SF2
SF3
SF4
2 Form A 3 Form A 4 Form A
2 Form B 1 Form B 4 Form B
Arrangement
Initial contact resistance, max.
(By voltage drop 6 V DC 1 A)
Contact material
Nominal switching
capacity
Rating
Max. switching power
(resistive)
Max. switching voltage
Max. carrying current
Mechanical (at 180
Expected
cpm) (resistive)
life (min.
operations) Electrical (at 20 cpm)
30 mΩ
Gold-flashed silver alloy
6 A 250 V AC, 6 A 30 V DC
1,500 VA, 180 W
30 V DC, 440 V AC
6 A DC, AC
107
3×104*1
105
Coil (at 25°C 77°F)
Nominal operating power
500 mW
Remarks
* Specifications will vary with foreign standards certification ratings.
*1
More than 105 operations when applying the nominal switching capacity to one
side of contact pairs of each Form A contact and Form B contact
*2
Measurement at same location as " Initial breakdown voltage " section
*3
Detection current: 10mA
*4 Excluding contact bounce time
*5
Half-wave pulse of sine wave: 11ms; detection time: 10µs
*6 Half-wave pulse of sine wave: 6ms
*7 Detection time: 10µs
*8 Refer to 5. Conditions for operation, transport and storage mentioned in
AMBIENT ENVIRONMENT (Page 61).
ORDERING INFORMATION
Ex. SF
2
DC 12 V
Contact arrangement
Coil voltage
2: 2 Form A 2 Form B
3: 3 Form A 1 Form B
4: 4 Form A 4 Form B
DC 5, 9, 12, 18, 21,
24, 36, 48, 60 V
UL/CSA, TÜV, SEV approved type is standard (SF2, SF4)
TÜV approved type is standard (SF3)
258
Max. operating speed
Initial insulation resistance*2
Between contact sets
Initial breakBetween open
down voltage*3 contacts
Between contact and coil
Operate time*4
(at nominal voltage)
Release time (without diode)*4
(at nominal voltage)
Temperature rise
(at nominal voltage)
Functional*5
Shock
resistance
Destructive*5
Vibration
resistance
Conditions for operation, transport and
storage*8
(Not freezing and
condensing at low
temperature)
Functional*7
Destructive
SF2
SF3
SF4
180 cpm (at nominal voltage)
Min. 1,000 MΩ at 500 V DC
2,500 Vrms
2,500 Vrms
2,500 Vrms
Approx. 17 ms
Approx. 18 ms
Approx. 7 ms
Approx. 6 ms
Max. 45°C with nominal coil voltage
and at 6 A switching current
Min. 294 m/s2 {30 G}
Min. 980 m/s2 {100 G}
117.6 m/s2 {12 G}, 10 to 55 Hz
at double amplitude of 2 mm
117.6 m/s2 {12 G}, 10 to 55 Hz
at double amplitude of 2 mm
Ambient
temp.
–40°C to +70°C –40°F to +158°F
Humidity
5 to 85% R.H.
Unit weight
37 g 1.31 oz
TYPICAL APPLICATIONS
• Signal
• Escalator
• Elevator
• Medical Instruments
• Railway
• Factory Automation
47 g 1.66 oz
SF
TYPES AND COIL DATA (at 20°C 68°F)
Contact
arrangement
SF2
SF3
SF4
Part No.
Nominal
voltage, V DC
Pick-up
voltage, VDC
(max.)
Drop-out
voltage, V DC
(min.)
Coil
resistance
Ω (±10%)
SF2-DC5V
SF2-DC9V
SF2-DC12V
SF2-DC18V
SF2-DC21V
SF2-DC24V
SF2-DC36V
SF2-DC48V
SF2-DC60V
SF3-DC5V
SF3-DC9V
SF3-DC12V
SF3-DC18V
SF3-DC21V
SF3-DC24V
SF3-DC36V
SF3-DC48V
SF3-DC60V
SF4-DC5V
SF4-DC9V
SF4-DC12V
SF4-DC18V
SF4-DC21V
SF4-DC24V
SF4-DC36V
SF4-DC48V
SF4-DC60V
5
9
12
18
21
24
36
48
60
5
9
12
18
21
24
36
48
60
5
9
12
18
21
24
36
48
60
3.75
6.75
9
13.5
15.75
14.4
27
36
45
3.75
6.75
9
13.5
15.75
14.4
27
36
45
3.75
6.75
9
13.5
15.75
14.4
27
36
45
0.5
0.9
1.2
1.8
2.1
2.4
3.6
4.8
6.0
0.5
0.9
1.2
1.8
2.1
2.4
3.6
4.8
6.0
0.75
0.9
1.8
1.8
2.1
3.6
3.6
7.2
9.0
50
Nominal
operating
current,
mA(±10%)
100
288
41.7
1.152
20.8
4.608
7.200
50
10.4
8.3
100
288
41.7
1.152
20.8
4.608
7.200
50
10.4
8.3
100
288
41.7
1.152
20.8
4.608
7.200
10.4
8.3
Nominal
operating
power, mW
Max. allowable
voltage, V DC
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
6
10.8
14.4
21.6
25.2
28.8
43.2
57.6
72
6
10.8
14.4
21.6
25.2
28.8
43.2
57.6
72
6
10.8
14.4
21.6
25.2
28.8
43.2
57.6
72
mm inch
DIMENSIONS
Schematic (Bottom view)
1) SF2
5
6
7
8
9
10
11
12
1
16±0.3
.630±.012
2
0.5
.020
5.08
.200
12.7
.500
12.7
.500
12.7
.500
3.5±0.3
.138±.012
PC board pattern (Bottom view)
53.3±0.3
2.098±.012
5
25.0
.984
6
7
2.54
.100
8
2.54
.100
10-1.4 DIA. HOLES
10-.055 DIA. HOLES
1
12.7
.500
7.62
.300
2
9
10
11
12
General tolerance: ±0.3 ±.012
Tolerance: ±0.1 ± .004
259
SF
2) SF3
mm inch
Schematic (Bottom view)
5
6
7
8
9
10
11
12
1
16±0.3
.630±.012
2
0.5
.020
5.08
.200
12.7
.500
12.7
.500
3.5±0.3
.138±.012
12.7
.500
PC board pattern (Bottom view)
53.3±0.3
2.098±.012
5
25.0
.984
6
7
10-1.4 DIA. HOLES
10-.055 DIA. HOLES
2.54
.100
2.54
.100
8
1
12.7
.500
7.62
.300
2
9
10
11
12
General tolerance: ±0.3 ±.012
Tolerance: ±0.1 ±.004
3) SF4
Schematic (Bottom view)
16±0.3
.630±.012
12.7
.500
12.7
.500
12.7
.500
13
5
14
6
15
7
16
8
7.62
.300
15
16
5
9
6
10
7
11
8
12
17
18
19
20
2
3.5±0.3
.138±.012
53.3±0.3
2.098±.012
33±0.3
1.299±.012
14
1
0.3
.012
5.08
.200
13
PC board pattern (Bottom view)
1
12.7
.500
7.62
.300
9
17
10
18
11
19
12
20
18-1.4 DIA. HOLES
18-.055 DIA. HOLES
2.54
.100
2
2.54
.100
7.62
.300
General tolerance: ±0.3 ±.012
Tolerance: ±0.1 ±.004
REFERENCE DATA
2. Coil temperature rise
3. Ambient temperature characteristics
Coil applied voltage: 120%V
Contact switching current: 6A
Tested sample: SF4-DC12V
Quantity: n = 6
60
Temperature rise, °C
50
Operate/release time, ms
Rate of
change, %
1. Operate/release time
40
30
Operate time
20
Max.
x
Min.
10
50
100
Drop-out
voltage
50
40
-40 -20
30
Pick-up
voltage
0
Inside the coil
20 40
Contact
-50
20
10
Max.
x
Min.
90
100
110
120
Coil applied voltage, %V
Release time
0
260
80
0
30
50
70
Ambient temperature, °C
-100
60 80
Ambient
temperature, °C
SF
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
Even when one contact is welded closed,
the other maintains a gap of greater than
0.5 mm .020 inch.
Card
1. Forced operation method
(2a2b, 3a1b, 4a4b types)
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.
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.
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.
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, 3a1b, 4a4b types)
Contact a
2
Body
separator
Contact b
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. High-efficiency 4-gap balanced
armature structure
(2a2b, 3a1b, 4a4b types)
The use of high-efficiency magnetically polarized circuits
and 4-gap balanced armature structure means that
springs are not required.
Does away with return faults due to fatigue
or breakage of the return spring, especially
stoppage during contact states.
5. 2a2b contact
3a1b 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.
261
SF
THE OPERATION OF SF RELAYS (when contacts are welded)
SF relays work to maintain a normal operating state even when overloading or short-circuit currents occur. It is also easy to include
weld detection circuits and safety circuits in the design to ensure safety even if contacts weld.
1) 2a2b Type
Form “b” Contact Weld
If the form “b” contacts (Nos. 1 and 3) weld, the armature becomes non-operational and the contact gap of the two form “a” contacts
is maintained at greater than 0.5 mm .020 inch. Reliable isolation is thus ensured.
No.4
No.1
No.4
No.1
No.3
No.2
No.3
No.2
Non-energized
If the No. 1 contact welds.
A gap of greater than 0.5 mm .020 inch is maintained at each of the two form "a" contacts (Nos.
2 and 4).
Energized (when no. 1 contact is welded)
Form “a” Contact Weld
If the two form “a” contacts (Nos. 2 and 4) weld, the armature becomes non-operational and the gap between the two form "b"
contacts is maintained at greater than 0.5 mm .020 inch. Reliable isolation is thus ensured.
No.4
No.1
No.4
No.1
No.3
No.2
No.3
No.2
Energized
If the No. 2 contact welds.
Each of the two form "b" contacts (Nos. 1 and 3)
maintains a gap of greater than 0.5 mm .020 inch.
Non-energized (when no. 2 contact is welded)
Contact Operation Table
The table below shows the state of the other contacts when the current through the welded form “a” contact is 0 V and the rated
voltage is applied through the form “b” contact.
No.4
No.1
No.3
Contact No.
Terminal No.
262
No.2
No.1
11–12
No.2
7–8
No.3
5–6
No.4
9–10
Contact No.
Contact No.
1
Welded
2
terminal
3
No.
4
State of other contacts
1
2
3
4
>0.5
>0.5
>0.5
>0.5
>0.5
>0.5
>0.5
>0.5
Note: Contact gaps are shown at the initial state.
If the contacts change state owing to loading/breaking
it is necessary to check the actual loading.
>0.5: contact gap is kept at min. 0.5 mm .020 inch
Empty cells: either closed or open
SF
2) 3a1b Type
Form “b” Contact Weld
If the form “b” contact (No. 3) welds, the armature becomes non-operational, the contact gaps at the three form “a” contacts are
maintained at greater than 0.5 mm .020 inch. Reliable isolation is thus ensured
No.4
No.1
No.4
No.1
No.3
No.2
No.3
No.2
Non-energized
If the No. 3 contact welds.
Each of the two form “a” contacts (Nos. 1, 2, and
4) maintain a gap of greater than 0.5 mm .020
inch.
Energized (when no. 3 contact is welded)
Form “a” Contact Weld
When the form “a” contacts (nos. 1, 2, and 4) weld, the armature remains in a non-returned state and the contact gap at the single
form “b” contact is maintained at greater than 0.5 mm .020 inch. Reliable isolation is thus ensured.
No.4
No.1
No.4
No.1
No.3
No.2
No.3
No.2
Energized
If the No. 2 contact welds.
The single form “b” contact (No. 3) maintains a
gap of greater than 0.5 mm .020 inch.
Non-energized (when no. 2 contact is welded)
Contact Operation Table
The table below shows the state of the other contacts when the current through the welded form “a” contact is 0 V and the rated voltage is applied through the form “b” contact.
No.4
No.1
No.3
Contact No.
Terminal No.
No.2
No.1
11–12
No.2
7–8
No.3
5–6
No.4
9–10
Contact No.
Contact No.
1
Welded
2
terminal
3
No.
4
State of other contacts
1
2
3
4
>0.5
>0.5
>0.5 >0.5
>0.5
>0.5
>0.5: contact gap is kept at min. 0.5 mm .020 inch
Empty cells: either closed or open
Note: Contact gaps are shown at the initial state.
If the contacts change state owing to loading/breaking
it is necessary to check the actual loading.
263
SF
3) 4a4b Type
Internal Contacts Weld
If the internal contacts (nos. 2, 3, 6, and 7) weld, the armature becomes non-operational and the contact gaps of each of the four form
“a” contacts are maintained at greater than 0.5 mm .020 inch. Reliable isolation 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 (Nos. 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
If the external contacts (nos. 1, 4, 5, and 8) weld, gaps of greater than 0.5 mm .020 inch are maintained between adjacent contacts
and the coil returns to an non-energized state.
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
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 (nos. 3, 5, and 7) maintains a contact gap of
greater than 0.5 mm .020 inch; each of the form
“b” contacts (nos. 4, 6, and 8) return to a closed
state.
Non-energized (when no. 1 contact is welded)
Energized
If external connections are made in series.
Even if one of the contacts welds, because the
other contacts operate independently, the contact
gaps are maintained at greater than 0.5 mm .020
inch.
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 when the current through the welded form “a” contact is 0 V and the rated voltage is applied through the form “b” contact.
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. 13–14 5–6 9–10 17–18 19–20 11–12 7–8 15–16
Contact No.
1
Contact No.
1
2 >0.5
3
Welded 4
≠
terminal
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 contacts change state owing to loading/breaking it is necessary to check the actual loading.
For Cautions for Use, see Relay Technical Information (Page 48 to 76).
264
9/1/2000
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