SF
π
53.3±0.3
2.098±.012
53.3±0.3
2.098±.012
53.3±0.3
2.098±.012
25.0
.984
16.5±0.3
.650±.012
33±0.3
1.299±.012
16.5±0.3
.650±.012
POLARISED, MONOSTABLE
SAFETY RELAY with
(mechanical linked) forced
contacts operation
FEATURES
• Forced operation contacts (2 Form A
2 Form B, 3 Form A 1 Form B)
25.0
.984
16.5±0.3
.650±.012
mm inch
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
(SF3 pending) (SF3 pending) (SF3 pending)
SF-RELA YS
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
Type SF2 SF3 SF4
Arrangement
2 Form A
2 Form B
Initial contact resistance, max.
(By voltage drop 6 V DC 1 A)
Contact material Gold-flashed silver alloy
Rating
(resistive)
Nominal switching
capacity
Max. switching power 1,500 VA, 180 W
Max. switching voltage 30 V DC, 440 V AC
6 A 250 V AC, 6 A 30 V DC
Max. carrying current 6 A DC, AC
Expected
life (min.
operations)
Coil (at 25°C
Mechanical (at 180
cpm) (resistive)
Electrical (at 20 cpm)
77°F
)
Nominal operating power 500 mW
Remarks
* Specifications will vary with foreign standards certification ratings.
*1
More than 10
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: 10 µ s
*6
Half-wave pulse of sine wave: 6ms
*7
Detection time: 10 µ s
*8
Refer to 5. Conditions for operation, transport and storage mentioned in
AMBIENT ENVIRONMENT (Page 61).
5
operations when applying the nominal switching capacity to one
3 × 10
3 Form A
1 Form B
30 m Ω
7
10
4
1
*
4 Form A
4 Form B
10
Characteristics (at 25°C
77°F
, 50% Relative humidity)
SF2 SF3 SF4
Max. operating speed 180 cpm (at nominal voltage)
Initial insulation resistance*
2
Between contact sets
Initial breakdown voltage*
Between open
3
contacts
Between con-
tact and coil
Operate time*
4
(at nominal voltage)
Release time (without diode)*
(at nominal voltage)
5
Temperature rise
(at nominal voltage)
Shock
resistance
Vibration
resistance
Conditions for operation, transport and
8
storage*
(Not freezing and
condensing at low
temperature)
Functional*
Destructive*
Functional*
Destructive
Ambient
temp.
Humidity 5 to 85% R.H.
5
7
Min. 1,000 M Ω at 500 V DC
2,500 Vrms
2,500 Vrms
2,500 Vrms
Approx. 17 ms Approx. 18 ms
4
Approx. 7 ms Approx. 6 ms
Max. 45 ° C with nominal coil voltage
and at 6 A switching current
2
{30 G}
2
{100 G}
2
{12 G}, 10 to 55 Hz
5
Min. 294 m/s
Min. 980 m/s
117.6 m/s
at double amplitude of 2 mm
2
117.6 m/s
{12 G}, 10 to 55 Hz
at double amplitude of 2 mm
–40 ° C to +70 ° C –40°F to +158°F
Unit weight 37 g 1.31 oz 47 g 1.66 oz
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
UL/CSA, TÜV, SEV approved type is standard (SF2, SF4)
TÜV approved type is standard (SF3)
258
DC 5, 9, 12, 18, 21,
24, 36, 48, 60 V
TYPICAL APPLICATIONS
• Signal
• Escalator
• Elevator
• Medical Instruments
• Railway
• Factory Automation
Ω ( ±
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.)
SF2-DC5V 5 3.75 0.5 50 100 500 6
SF2-DC9V 9 6.75 0.9 500 10.8
SF2-DC12V 12 9 1.2 288 41.7 500 14.4
SF2-DC18V 18 13.5 1.8 500 21.6
SF2-DC21V 21 15.75 2.1 500 25.2
SF2-DC24V 24 14.4 2.4 1.152 20.8 500 28.8
SF2-DC36V 36 27 3.6 500 43.2
SF2-DC48V 48 36 4.8 4.608 10.4 500 57.6
SF2-DC60V 60 45 6.0 7.200 8.3 500 72
SF3-DC5V 5 3.75 0.5 50 100 500 6
SF3-DC9V 9 6.75 0.9 500 10.8
SF3-DC12V 12 9 1.2 288 41.7 500 14.4
SF3-DC18V 18 13.5 1.8 500 21.6
SF3-DC21V 21 15.75 2.1 500 25.2
SF3-DC24V 24 14.4 2.4 1.152 20.8 500 28.8
SF3-DC36V 36 27 3.6 500 43.2
SF3-DC48V 48 36 4.8 4.608 10.4 500 57.6
SF3-DC60V 60 45 6.0 7.200 8.3 500 72
SF4-DC5V 5 3.75 0.75 50 100 500 6
SF4-DC9V 9 6.75 0.9 500 10.8
SF4-DC12V 12 9 1.8 288 41.7 500 14.4
SF4-DC18V 18 13.5 1.8 500 21.6
SF4-DC21V 21 15.75 2.1 500 25.2
SF4-DC24V 24 14.4 3.6 1.152 20.8 500 28.8
SF4-DC36V 36 27 3.6 500 43.2
SF4-DC48V 48 36 7.2 4.608 10.4 500 57.6
SF4-DC60V 60 45 9.0 7.200 8.3 500 72
Drop-out
voltage, V DC
(min.)
Coil
resistance
10%)
Nominal
operating
current,
mA( ± 10%)
Nominal
operating
power, mW
SF
Max. allowable
voltage, V DC
DIMENSIONS
1) SF2
25.0
.984
7.62
.300
5.08
.200
12.7
12.7
.500
.500
53.3±0.3
2.098±.012
6587
1
2
109
General tolerance: ±0.3 ±.012
12.7
.500
3.5±0.3
.138±.012
1211
16±0.3
.630±.012
0.5
.020
12.7
.500
Schematic (Bottom view)
5
1
2
678
9 101112
PC board pattern (Bottom view)
10-1.4 DIA. HOLES
2.54
10-.055 DIA. HOLES
2.54
.100
.100
Tolerance: ±0.1 ± .004
mm
inch
259
SF
-40 -20 0
20
40 60 80
-50
100
50
-100
Rate of
change, %
Ambient
temperature, °C
Pick-up
voltage
Drop-out
voltage
12.7
.500
53.3±0.3
2.098±.012
12.7
.500
12.7
.500
5.08
.200
6587
109
1
2
1211
16±0.3
.630±.012
12.7
.500
3.5±0.3
.138±.012
0.5
.020
25.0
.984
7.62
.300
5678
9 101112
1
2
2.54
.100
2.54
.100
10-1.4 DIA. HOLES
10-.055 DIA. HOLES
General tolerance: ±0.3 ±.012
PC board pattern (Bottom view)
Schematic (Bottom view)
Tolerance: ±0.1 ±.004
2) SF3
3) SF4
mm
inch
3.5±0.3
12.7
12.7
33±0.3
1.299±.012
7.62
.300
5.08
.200
12.7
.500
.500
53.3±0.3
2.098±.012
1413 1615
65
1
2
109
1817 2019
.500
.138±.012
87
1211
General tolerance: ±0.3 ±.012
REFERENCE DATA
1. Operate/release time 2. Coil temperature rise
Coil applied voltage: 120%V
Contact switching current: 6A
16±0.3
.630±.012
0.3
.012
7.62
.300
12.7
.500
7.62
.300
Schematic (Bottom view)
13
14615716
1
5
9171018111912
2
8
20
PC board pattern (Bottom view)
18-1.4 DIA. HOLES
18-.055 DIA. HOLES
2.54
.100
2.54
.100
Tolerance: ±0.1 ±.004
3. Ambient temperature characteristics
Tested sample: SF4-DC12V
Quantity: n = 6
50
40
30
20
Operate/release time, ms
10
0
260
Operate time
80 10090 120110
Release time
Coil applied voltage, %V
Max.
x
Min.
Max.
x
Min.
60
50
40
30
Temperature rise, °C
20
10
0
Inside the coil
Contact
30 50 70
Ambient temperature, °C
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 o v erloading and other
circuit abnormalities (unforeseen
1. Forced operation method
(2a2b, 3a1b, 4a4b types)
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
Card
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.
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
Even when one contact is welded closed,
Contact a
Contact b
Weld
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
SF
2. Independent operation method
(4a4b type)
3. Separate chamber method
(2a2b, 3a1b, 4a4b types)
4. High-efficiency 4-gap balanced
armature structure
(2a2b, 3a1b, 4a4b types)
External NO
2
contact weld
Return
Contact a
Body
separator
Contact b
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
The use of high-efficiency magnetically polarized circuits
and 4-gap balanced armature structure means that
springs are not required.
1
Card
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.
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.
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
If the No. 1 contact welds.
No.1
A gap of greater than 0.5 mm .020 inch is maintained at each of the two form "a" contacts (Nos.
No.3
Non-energized
No.2
No.3
Energized (when no. 1 contact is welded)
No.2
2 and 4).
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.3
Energized
No.1
No.2
No.4
No.3
Non-energized (when no. 2 contact is welded)
No.1
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.
No.2
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.3
Contact No. No.1 No.2 No.3 No.4
Terminal No. 11–12 7–8 5–6 9–10
No.1
No.2
Contact No.
Contact No.
Welded
terminal
No.
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.
State of other contacts
1234
1 >0.5 >0.5
2 >0.5 >0.5
3 >0.5 >0.5
4 >0.5 >0.5
>0.5: contact gap is kept at min. 0.5 mm .020 inch
Empty cells: either closed or open
262
h
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
SF
No.4
No.1
No.4
If the No. 3 contact welds.
No.1
Each of the two form “a” contacts (Nos. 1, 2, and
4) maintain a gap of greater than 0.5 mm .020
No.3
Non-energized
No.2
No.3
Energized (when no. 3 contact is welded)
No.2
inch.
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.3
Energized
No.1
No.2
No.4
No.3
Non-energized (when no. 2 contact is welded)
No.1
If the No. 2 contact welds.
The single form “b” contact (No. 3) maintains a
gap of greater than 0.5 mm .020 inch.
No.2
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.3
Contact No. No.1 No.2 No.3 No.4
Terminal No. 11–12 7–8 5–6 9–10
No.1
No.2
Contact No.
Contact No.
Welded
terminal
No.
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.
State of other contacts
1234
1 >0.5
2 >0.5
3 >0.5 >0.5 >0.5
4 >0.5
>0.5: contact gap is kept at min. 0.5 mm .020 inc
Empty cells: either closed or open
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 f our f orm
“a” contacts are maintained at greater than 0.5 mm .020 inch. Reliable isolation is thus ensured.
≠
No.8
No.7
No.1
No.2
No.8
No.7
No.1
No.2
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
No.6
No.5
Non-energized
No.3
No.4
No.6
No.5
Energized (when no. 2 contact is welded)
No.3
No.4
.020 inch.
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.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)
If the No. 1 contact welds.
No.1
The adjacent No. 2 contact maintains a gap of
No.2
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
No.3
greater than 0.5 mm .020 inch; each of the form
No.4
“b” contacts (nos. 4, 6, and 8) return to a closed
state.
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.
Energized
Non-energized
Weld
Contact gap
min 0.5 mm .020 inch
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.7
No.6
No.5
Contact No. No.1 No.2 No.3 No.4
Terminal No.
13–14 5–6 9–10 17–18
No.1
No.2
No.3
No.4
No.5 No.6 No.7 No.8
19–20 11–12 7–8 15–16
Contact No.
Contact No.
12345678
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
Welded
terminal
4 ≠ >0.5 >0.5
5 >0.5 ≠ >0.5 ≠
No.
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
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.
State of other contacts
>0.5 ≠ >0.5
>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
For Cautions for Use, see Relay Technical Information (Page 48 to 76).
264
9/1/2000 All Rights Reserved, © Copyright Matsushita Electric Works, Ltd.
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