General-purpose Basic Switch
A
High-capacity Switch Capable of
Handling 20 A Loads with Large
Inrush Currents
• Same shape as OMRON Z Basic Switches except in pin plunger
position, yet endures inrush currents as large as 75 A.
Be sure to read
Safety Precautions
on page 5 and
Safety
Precautions for All Basic Switches.
CSM_A_DS_E_2_1
Model Number Structure
Model Number Legend
Ordering Information
Terminal
Actuator
Pin plunger
Short spring plunger
Panel mount plunger
Panel mount roller plunger
Panel mount cross roller plunger
Short hinge lever
Hinge lever
Short hinge roller lever
Hinge roller lever
Solder terminal
Model
A-20G
A-20GD
A-20GQ
A-20GQ22
---
A-20GV21
A-20GV
A-20GV22
A-20GV2
Screw terminal (-B)
Model
A-20G-B
A-20GD-B
A-20GQ-B
A-20GQ22-B
A-20GQ21-B
A-20GV21-B
A-20GV-B
A-20GV22-B
A-20GV2-B
A - 20 G
@
-
@
(1) (2) (3) (4)
(1) Ratings
20
G
None
D
Q
Q21
Q22
V
V2
V21
V22
: 20 A (250 VAC)
: 0.5 m
: Pin plunger
: Short spring plunger
: Panel mount plunger
: Panel mount cross roller plunger
: Panel mount roller plunger
: Hinge lever
: Hinge roller lever
: Short hinge lever
: Short hinge roller lever
(2) Contact Gap
(3) Actuator
(4) Terminals
None : Solder terminal
B
: Screw terminal (with toothed washer)
Specifications
Ratings
Non-inductive load (A)
Rated
voltage
(V)
125 VAC
250 VAC
500 VAC
8 VDC
14 VDC
30 VDC
125 VDC
250 VDC
Resistive
load
NC
20
20
15
20
20
6
0.5
0.25
NO
Lamp load
NC
7.5
7.5
4
3
3
3
0.5
0.25
1.5
1.5
1.5
0.5
0.25
NO
Inductive load (A)
Inductive
load
NC
20
20
10
20
15
5
0.05
0.03
NO
Motor load
NC
12.5
8.3
2
12.5
12.5
5
0.05
0.03
NO
Certified Standard Ratings
Ask your OMRON representative for information on certified models.
UL/CSA (General ratings only)
Rated voltage
125 VAC
250 VAC
480 VAC
125 VDC
250 VDC
Model
A-20G
1 HP 10 A "L"
2 HP
20 A
0.5 A
0.25 A
Note: 1. The above values are for steady-state current.
2. Inductive load has a power factor of 0.4 min. (AC) and a time constant
of 7 ms max. (DC).
3. Lamp load has an inrush current of 10 times the steady-state current.
4. Motor load has an inrush current of 6 times the steady-state current.
5. The ratings values apply under the following test conditions:
(1) Ambient temperature: 20±2°C
(2) Ambient humidity: 65±5%RH
(3) Operating frequency: 20 operations/min
Accessories (Terminal Covers, and Separators): Refer to Z/A/X/DZ Common Accessories.
1
A
Characteristics
Operating speed
Operating
frequency
Mechanical
Electrical
0.01 mm to 1m/s
*
1
240 operations/min
20 operations/min
100 MΩ min. (at 500 VDC)
15 mΩ max. (initial value)
1,000 VAC, 50/60 Hz for 1 min between
terminals of the same polarity
2,000 VAC, 50/60 Hz for 1 min between the
current-carrying metal parts and the ground,
and between each terminal and non-current-
carrying metal parts
10 to 55 Hz, 1.5-mm double amplitude
*
2
1,000 m/s
2
max.
300 m/s
2
max.
*
1
*
2
1,000,000 operations min.
500,000 operations min.
IP00
Class I
−
25°C to 80°C (with no icing)
35% to 85%RH
Approx. 22 to 58 g
10
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7 0.8
Engineering Data
Mechanical Durability (A-20G)
Durability (x10
4
operations)
1,000
700
500
300
Insulation resistance
Contact resistance
Ambient temperature: 20
±
2
°
C
Ambient humidity: 65
±
5%RH
Without load
Operating frequency:
240 operations/min
Dielectric strength
100
70
50
30
Vibration
resistance
Shock re-
sistance
Durability
Malfunction
Destruction
Malfunction
Mechanical
Electrical
Overtravel (mm)
Degree of protection
Degree of protection
against electric shock
Ambient operating temperature
Ambient operating humidity
Weight
Electrical Durability (A-20G)
Durability (x10
4
operations)
1,000
700
500
300
Proof tracking index (PTI)
175
Ambient temperature: 20
±
2
°
C
Ambient humidity: 65
±
5%RH
Operating frequency:
20 operations/min
125 VAC, cosφ = 1
125 VAC,
cosφ = 0.4
*1. The value is for the pin plunger. (Contact your OMRON representative for
other models.)
*2. Malfunction: 1 ms max.
100
70
250 VAC,
cosφ = 1
Contact Specification
Shape
Contacts
Material
Gap (standard value)
Inrush current
NC
NO
Rivet
Silver alloy
0.5 mm
75 A max.
75 A max.
50
30
250 VAC, cosφ = 0.4
10
0
5
10
15
20
25
Switching current (A)
Structure
Contact Form (SPDT)
COM
NC
NO
Dimensions
Terminals
Screw Terminals (-B)
(Unit: mm)
Mounting Holes
Use M4 mounting screws with plane washers or spring washers to
securely mount the Switch. Tighten the screws to a torque of 1.18 to
1.47 N·m.
Two, 4.2 dia. mounting
holes or M4
20
COM
NO
9.2
20
17.45±0.2
NC
25.4±0.1
1
3
2
49.2
Three, M4
×
5.5
Terminal screws
(with toothed washer)
The Switch can be panel mounted, provided that the hexagonal nut of
the actuator is tightened to a torque of 2.94 to 4.9 N·m.
Panel Mount Plunger
12.5
+ 0.2
0
dia.
Solder Terminal (-A)
("-A" is not included in the model numbers.)
Panel Mount Roller Plunger
12.5
+ 0.2
0
dia.
6.4
25.4±0.1
3
1 NO
COM
NC
2
5
+ 0.2
0
11.9
13
+ 0.2
0
17.45±0.2
49.2
Note: 1. Appropriate terminal screw tightening torque: 0.78 to 1.18 N·m.
2. Unless otherwise specified, a tolerance of
±0.4
mm applies to all dimensions.
2
A
Dimensions and Operating Characteristics
The models, illustrations, and graphics are for screw-terminal models. (The dimensions for models that are omitted here are the same as for pin-plunger models.)
Pin Plunger
A-20G-B
PT
19.05±0.25
2.3 dia.
4.2
+0.075
dia. hole
−0.025
2.3SR *
OP
24.2
9.2
4.2
+0.075
dia.
−0.025
4.36
+0.1
dia.
−0.05
11.9
25.4±0.1
49.2
17.45±0.2
* Stainless-steel plunger
Short Spring Plunger
A-20GD-B
PT
15 dia.
19.05±0.25
11.2 dia.
7.15
11.9SR *
dia.
7.5
OP
24.2
* Stainless-steel plunger
Panel Mount Plunger
A-20GQ-B
PT
19.05±0.25
8.35 dia.
11.9SR *1
M12
×
1 mounting screw
OP
13.1
*2
Note: Do not use both M12
mounting screw and
Two hexagon nuts
mounting holes at the
(2 t
×
14 width across flats)
same time.
Two lock nuts
(2 t
×
15.6 width across flats)
16.3
16 dia.
*1
Stainless-steel plunger
*2 Incomplete screw part with a maximum length of 1.5 mm.
Panel Mount Roller Plunger
A-20GQ22-B
PT
19.05±0.25
12.7 dia.
×
4.8 *1
Two hexagon nuts
(3 t
×
17 width across flats)
OP
15.5
*2
M12
×
1 mounting screw
16.3
16 dia.
Note: Do not use both M12
mounting screw and
mounting holes at the
same time.
*1
Stainless-steel roller
*2 Incomplete screw part with a maximum length of 1.5 mm.
Panel Mount Cross Roller Plunger
PT
A-20GQ21-B
OP
15.5
19.05±0.25
12.7 dia.
×
4.8 *1
Two hexagon nuts
(3 t
×
17 width across flats)
M12
×
1 mounting screw
*2
16.3
16 dia.
Note: Do not use both M12
mounting screw and
mounting holes at the
same time.
*1
Stainless-steel roller
*2 Incomplete screw part with a maximum length of 1.5 mm.
Note: Unless otherwise specified, a tolerance of
±0.4
mm applies to all dimensions.
Operating Characteristics
Operating force
Release force
Pretravel
Over Travel
Movement differential
Operating Position
Model
OF
RF min.
PT max.
OT min.
MD max.
OP
A-20G-B
3.92 to 6.13 N
2.79 N
1.3 mm
0.25 mm
0.2 mm
16.3±0.4 mm
A-20GD-B
3.92 to 6.13 N
2.79 N
1.3 mm
3 mm
0.2 mm
26.2±0.5 mm
A-20GQ-B
3.92 to 6.13 N
2.79 N
1.3 mm
5.6 mm
0.2 mm
21.8±0.8 mm
A-20GQ22-B
6.18 N max.
2.75 N
1.3 mm
3.58 mm
0.35 mm
33.4±1.2 mm
A-20GQ21-B
6.18 N max.
2.75 N
1.3 mm
3.58 mm
0.35 mm
33.4±1.2 mm
3
A
Safety Precautions
Refer to
Safety Precautions for All Basic Switches.
Precautions for Safe Use
Terminal Connection
When soldering lead wires to the Switch, make sure that the capacity
of the soldering iron is 60 W maximum. Do not take more than 5 s to
solder any part of the Switch. The characteristics of the Switch will
deteriorate if a soldering iron with a capacity of more than 60 W is
applied to any part of the Switch for 5 s or more.
•
Do not use the switch in locations subject to hot water (greater than
60°C) or in water vapor.
•
Do not use the switch outside the specified temperature and
atmospheric conditions.
The permissible ambient temperature depends on the model.
(Refer to the specifications in this catalog.) Sudden thermal
changes may cause thermal shock to distort the switch and result
in faults.
Incorrect
Correct
Separate the
installation lo-
cation from
heat sources.
Operation
•
Make sure that the switching frequency or speed is within the
specified range.
1.If the switching speed is extremely slow, the contact may not be
switched smoothly, which may result in a contact failure or
contact welding.
2.If the switching speed is extremely fast, switching shock may
damage the Switch soon. If the switching frequency is too high,
the contact may not catch up with the speed.
The rated permissible switching speed and frequency indicate the
switching reliability of the Switch.
The life of a Switch is determined at the specified switching speed.
The life varies with the switching speed and frequency even when
they are within the permissible ranges. In order to determine the
life of a Switch model to be applied to a particular use, it is best to
conduct an appropriate durability test on some samples of the
model under actual conditions.
•
Make sure that the actuator travel does not exceed the permissible
OT position. The operating stroke must be set to 70% to 100% of
the rated OT.
•
Mount a cover if the switch is to be installed in a location where
worker inattention could result in incorrect operation or accidents.
Incorrect
Correct
(preventing malfunctions)
Precautions for Correct Use
Mounting Location
•
Do not use the switch alone in atmospheres such as flammable or
explosive gases. Arcing and heat generation associated with
switching may cause fires or explosions.
•
Switches are generally not constructed with resistance against
water. Use a protective cover to prevent direct spraying if the switch
is used in locations subject to splashing or spurting oil or water, dust
adhering.
Incorrect
Correct
•
Subjecting the switch to continuous vibration or shock may result in
contact failure or faulty operation due to abrasion powder and in
reduced durability. Excessive vibration or shock will cause the
contacts to operate malfunction or become damaged. Mount the
switch in a location that is not subject to vibration or shock and in a
direction that does not subject the switch to resonance.
•
If silver contacts are used with relatively low frequency for a long
time or are used with microloads, the sulfide coating produced on
the contact surface will not be broken down and contact faults will
result. Use a microload switch that uses gold contacts.
•
Do not use the switch in atmospheres with high humidity or heat or
in harmful gases, such as sulfide gas (H
2
S, SO
2
), ammonia gas
(NH
3
), nitric acid gas (HNO
3
), or chlorine gas (Cl
2
). Doing so may
impair functionality, such as with damage due to contacting faults
or corrosion.
•
The switch includes contacts. If the switch is used in an atmosphere
with silicon gas, arc energy may cause silicon oxide (SiO
2
) to
accumulate on the contacts and result in contact failure. If there is
silicon oil, silicon filling, silicon wiring, or other silicon products in the
vicinity of the switch, use a contact protection circuit to limit arcing
and remove the source of the silicon gas.
Terminal box
Terminal box
Panel-mounting model (A-20GQ@)
•
If a Switch is side-mounted with screws, remove the hexagonal nut
of the actuator.
•
If a Switch is side-mounted and secured with screws, make sure
that the angle or speed of the actuating object is not excessively
large or too high, otherwise the Switch may be damaged.
•
If a Switch is panel-mounted, pay utmost attention to make sure
that the actuating speed or OT distance is not excessively high or
large. Not doing so may damage the Switch.
•
Install the switch in a location that is not directly subject to debris
and dust from cutting. The actuator and the switch body must be
protected from accumulated cutting debris and dirt.
Incorrect
Correct
Accessories (Order Separately)
Refer to Z/A/X/DZ Common Accessories for details about Terminal
Covers, Separators, and Actuators.
5