258
SF
POLARISED, MONOSTABLE
SAFETY RELAY with
(mechanical linked) forced
contacts operation SF-RELAYS
(SF3 pending) (SF3 pending) (SF3 pending)
π
FEATURES
• 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
enables to plan a circuit to detect w elding
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)
25.0
.984
16.5±0.3
.650±.012
53.3±0.3
2.098±.012
25.0
.984
16.5±0.3
.650±.012
53.3±0.3
2.098±.012
33±0.3
1.299±.012
16.5±0.3
.650±.012
53.3±0.3
2.098±.012
mm inch
SPECIFICATIONS
ORDERING INFORMATION
Ex. SF 2 DC 12 V
Contact arrangement Coil voltage
DC 5, 9, 12, 18, 21,
24, 36, 48, 60 V
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)
TYPICAL APPLICATIONS
• Signal
• Escalator
• Elevator
• Medical Instruments
• Railway
• Factory Automation
Remarks
* Specifications will vary with foreign standards certification ratings.
*1
More than 10
5
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: 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).
Contact
Type SF2 SF3 SF4
Arrangement 2 Form A
2 Form B 3 Form A
1 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 30 V DC, 440 V AC
Max. carrying current 6 A DC, AC
Expected
life (min.
operations)
Mechanical (at 180
cpm) (resistive) 10
7
Electrical (at 20 cpm) 3
×
10
4
*
1
10
5
Coil
(at 25°C
77°F
)
Nominal operating power 500 mW
Characteristics
(at 25°C
77°F
, 50% Relative humidity)
SF2 SF3 SF4
Max. operating speed 180 cpm (at nominal voltage)
Initial insulation resistance*
2
Min. 1,000 M
Ω
at 500 V DC
Initial break-
down voltage*
3
Between con-
tact sets
2,500 Vrms
Between open
contacts
2,500 Vrms
Between con-
tact and coil
2,500 Vrms
Operate time*
4
(at nominal voltage) Approx. 17 ms Approx. 18 ms
Release time (without diode)*
4
(at nominal voltage) Approx. 7 ms Approx. 6 ms
Temperature rise
(at nominal voltage) Max. 45
°
C with nominal coil voltage
and at 6 A switching current
Shock
resistance Functional*
5
Min. 294 m/s
2
{30 G}
Destructive*
5
Min. 980 m/s
2
{100 G}
Vibration
resistance
Functional*
7
117.6 m/s
2
{12 G}, 10 to 55 Hz
at double amplitude of 2 mm
Destructive 117.6 m/s
2
{12 G}, 10 to 55 Hz
at double amplitude of 2 mm
Conditions for oper-
ation, transport and
storage*
8
(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 37 g 1.31 oz 47 g 1.66 oz
259
SF
TYPES AND COIL DATA (at 20°C 68°F)
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
SF2
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
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
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
DIMENSIONS
1) SF2
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
5
1
2
678
9 101112
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)
Tolerance: ±0.1 ± .004
Schematic (Bottom view)
mm
inch
260
SF
1. Operate/release time 2. Coil temperature rise
Coil applied voltage: 120%V
Contact switching current: 6A
3. Ambient temperature characteristics
Tested sample: SF4-DC12V
Quantity: n = 6
10
20
30
0
40
50
60
30 50 70
Temperature rise, °C
Ambient temperature, °C
Inside the coil
Contact
-40 -20 0 20 40 60 80
-50
100
50
-100
Rate of
change, %
Ambient
temperature, °C
Pick-up
voltage
Drop-out
voltage
3) SF4
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
General tolerance: ±0.3 ±.012
PC board pattern (Bottom view)
Schematic (Bottom view)
Tolerance: ±0.1 ±.004
12.7
.500
53.3±0.3
2.098±.012
12.7
.500
12.7
.500
5.08
.200
65
1817 2019
87
109
1413 1615
1
2
1211
16±0.3
.630±.012
12.7
.500
7.62
.300
7.62
.300
3.5±0.3
.138±.012
0.3
.012
33±0.3
1.299±.012
7.62
.300
REFERENCE DATA
10
20
30
0
40
50
80 10090 120110
Min.
Max.
Operate time
Release time Min.
Max.
x
x
Operate/release time, ms
Coil applied voltage, %V
2) SF3
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
mm
inch
261
SF
Structure Operation
1. Forced operation method
(2a2b, 3a1b, 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 b y 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, 3a1b, 4a4b types)
In independent chambers, the contacts "a" and "b" are
kept apart by a body/card separator or by the card itself. Prev ents 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. 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.
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 rela y suff ers o verloading 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.
262
SF
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.
F orm “a” Contact Weld
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.4
No.3
No.1
No.2
Energized
No.4
No.3
No.1
No.2
Non-energized (when no. 2 contact is welded)
No.4
No.3
No.1
No.2
Contact No. No.1 No.2 No.3 No.4
Terminal No. 11–12 7–8 5–6 9–10
State of other contacts
1234
Welded
terminal
No.
1 >0.5 >0.5
2 >0.5 >0.5
3 >0.5 >0.5
4 >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
Contact No.
Contact No.
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.
Contact Operation Table
1) 2a2b Type
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.
F orm “b” Contact Weld
If the No. 1 contact welds.
A gap of greater than 0.5 mm .020 inch is main-
tained at each of the two form "a" contacts (Nos.
2 and 4).
No.4
No.3
No.1
No.2
Non-energized
No.4
No.3
No.1
No.2
Energized (when no. 1 contact is welded)
THE OPERATION OF SF RELAYS (when contacts are welded)
SF relays w ork 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.
263
SF
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 volt-
age is applied through the form “b” contact.
Contact Operation Table
No.4
No.3
No.1
No.2
Contact No. No.1 No.2 No.3 No.4
Terminal No. 11–12 7–8 5–6 9–10
State of other contacts
1234
Welded
terminal
No.
1 >0.5
2 >0.5
3 >0.5 >0.5 >0.5
4 >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 inc
h
Empty cells: either closed or open
Contact No.
Contact No.
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.
No.4
No.3
No.1
No.2
Non-energized
No.4
No.3
No.1
No.2
Energized (when no. 3 contact is welded)
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.
F orm “a” Contact Weld
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.4
No.3
No.1
No.2
Energized
No.4
No.3
No.1
No.2
Non-energized (when no. 2 contact is welded)
2) 3a1b Type
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
F orm “b” Contact Weld
264
SF
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.
13–14 5–6 9–10 17–18
No.5 No.6 No.7 No.8
19–20 11–12 7–8 15–16
State of other contacts
12345678
Welded
terminal
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
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
≠
: contact closed
Empty cells: either
closed or open
Contact No.
Contact No.
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 volt-
age is applied through the form “b” contact.
Contact Operation Table
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.
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)
3) 4a4b Type
If the internal contacts (nos. 2, 3, 6, and 7) w eld, 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.
Internal 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.
External Contacts Weld
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 Contact gap
min 0.5 mm .020 inch
Weld
Non-energized
If the No. 1 contact welds.
The adjacent No. 2 contact maintains a gap of
greater than 0.5 mm .020 inch. The other con-
tacts, because the coil is not energized, return to
their normal return state; each of form “a” con-
tacts (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.
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)
For Cautions for Use, see Relay Technical Information (Page 48 to 76).
9/1/2000 All Rights Reserved, © Copyright Matsushita Electric Works, Ltd.
Go To Online Catalog
