Single-phase Current Relay
K8AK-AS
Ideal for Current Monitoring for
Industrial Facilities and Equipment.
• Monitor for overcurrents or undercurrents.
• Use commercially available CTs (CT current on secondary
side: 0 to 1 A or 0 to 5 A).
• Manual resetting and automatically resetting supported by one
Relay.
• Startup lock and operating time can be set separately.
• One SPDT output relay, 5 A at 250 VAC (resistive load).
• Output relay can be switched between normally open and
normally closed.
• Output status can be monitored using LED indicator.
• Inputs are isolated from the power supply.
Refer to
Safety Precautions
on page 9.
Refer to page 8 for commonly asked questions.
For the most recent information on models that have been certified for
safety standards, refer to your OMRON website.
Ordering Information
List of Models
Setting range
2 to 20 mA AC/DC,
10 to 100 mA AC/DC,
50 to 500 mA AC/DC
0.1 to 1 A AC/DC,
0.5 to 5 A AC/DC,
0.8 to 8 A AC/DC
10 to 100 A AC*,
20 to 200 A AC*
Power supply voltage
24 VAC/DC
100 to 240 VAC
24 VAC/DC
100 to 240 VAC
24 VAC/DC
100 to 240 VAC
Model
K8AK-AS1 24 VAC/DC
K8AK-AS1 100-240 VAC
K8AK-AS2 24 VAC/DC
K8AK-AS2 100-240 VAC
K8AK-AS3 24 VAC/DC
K8AK-AS3 100-240 VAC
*1 The K8AK-AS3 is designed to be used in combination with an OMRON K8AC-CT200L Current Transformer (CT). (Direct input is not possible.)
Accessory (Order Separately)
●OMRON
CT
Appearance
Input range
Applicable
Relay
Model
●Commercially
Available CTs*
Appearance
CT current on secondary
side
Applicable Relay
10 to 100 A AC,
K8AK-AS3
20 to 200 A AC
K8AC-CT200L
0 to 1 A AC,
0 to 5 A AC
K8AK-AS2
* If you use a commercially available CT, do not exceed the overload
capacity of the K8AK-AS2.
1
K8AK-AS
Ratings and Specifications
Input Range
Model
Range
*1
0 to 20 mA AC/DC
K8AK-AS1
0 to 100 mA AC/DC
0 to 500 mA AC/DC
0 to 1 A AC/DC
K8AK-AS2
0 to 5 A AC/DC
0 to 8 A AC/DC
0 to 100 A AC
K8AK-AS3
Connection
terminal
I1-COM
I2-COM
I3-COM
I1-COM
I2-COM
I3-COM
I2-COM
10 to 100 A AC
*2
,
20 to 200 A AC
*2
0.1 to 1 A AC/DC,
0.5 to 5 A AC/DC,
0.8 to 8 A AC/DC
Setting range
2 to 20 mA AC/DC,
10 to 100 mA AC/
DC, 50 to 500 mA
AC/DC
Input impedance
Approx. 5
Ω
Approx. 1
Ω
Approx. 0.2
Ω
Approx. 0.12
Ω
(Load : 0.5 VA)
Approx. 0.02
Ω
(Load : 1.5 VA)
Approx. 0.02
Ω
(Load : 3 VA)
---
Input type
Direct input
Direct input
Direct input
Direct input
or commer-
cially avail-
able CT
Continuous input at
120% of maximum input
1 s at 150%
Overload capacity
0 to 200 A AC
I3-COM
---
OMRON CT Continuous input at 120% with
an OMRON CT (K8AC-
CT200L).
OMRON CT 30 s at 200%
1 s at 600%
* CT capacity on primary side.
*1 The range is selected using connected terminals.
*2 The K8AK-AS3 is designed to be used in combination with an OMRON K8AC-CT200L Current Transformer (CT). (Direct input is not possible.)
Ratings
Power supply voltage
Power consumption
Isolated power supply
24 VAC/DC
100 to 240 VAC
24 VAC/DC: 2.0 VA/1.1 W max.
100 to 240 VAC: 4.6 VA max.
10% to 100% of the maximum value of the setting range
K8AK-AS1: 2 to 20 mA AC/DC
10 to 100 mA AC/DC
50 to 500 mA AC/DC
K8AK-AS2: 0.1 to 1 A AC/DC (Compatible with commercially available CTs.)
0.5 to 5 A AC/DC (Compatible with commercially available CTs.)
0.8 to 8 A AC/DC
K8AK-AS3: When used with the OMRON CT (K8AC-CT200L).
10 to 100 A AC
20 to 200 A AC
100% operation at set value
5% to 50% of operating value
Manual reset/automatic reset (switchable)
Note:
Manual reset: Turn OFF power supply for 1 s or longer.
0.1 to 30 s
0 to 30 s
(The startup lock timer starts when the input has reached approximately 30% or more of the set value.)
Note:
Enabled only for overcurrent operation.
Power (PWR): Green, Relay output (RY): Yellow, Alarm outputs (ALM): Red
Refer to
Input Range
on this page.
One SPDT relay (NO/NC switched using DIP switch.)
Rated load
Resistive load
5 A at 250 VAC
5 A at 30 VDC
Maximum switching capacity: 1,250 VA, 150 W
Minimum load: 5 VDC, 10 mA (reference values)
Mechanical life: 10 million operations min.
Electrical life: 5 A at 250 VAC or 30 VDC: 50,000 operations
3 A at 250 VAC/30 VDC:100,000 operations
−20
to 60°C (with no condensation or icing)
−25
to 65°C (with no condensation or icing)
25% to 85% (with no condensation)
25% to 85% (with no condensation)
2,000 m max.
0.49 to 0.59 N·m
Operating value setting range (SV)
Operating value
Reset value setting range (HYS.)
Reset method
Operating time setting range (T)
Startup lock time setting range (LOCK)
Note:
Enabled only for overcurrent operation.
Indicators
Input impedance
Output relays
Output relay ratings
Ambient operating temperature
Storage temperature
Ambient operating humidity
Storage humidity
Altitude
Terminal screw tightening torque
2
K8AK-AS
Terminal wiring method
Recommended wire
Solid wire: 2.5 mm
2
Twisted wires: AWG16, AWG18
Note: 1.
Ferrules with insulating sleeves must be used with twisted wires.
2.
Two wires can be twisted together.
Recommended ferrules
Al 1,5-8BK (for AWG16) manufactured by Phoenix Contact
Al 1-8RD (for AWG18) manufactured by Phoenix Contact
Al 0,75-8GY (for AWG18) manufactured by Phoenix Contact
N1.5
PC and ABS, UL 94 V-0
Approx. 150 g
Mounts to DIN Track
22.5
×
90
×
100 mm (W×H×D)
Case color
Case material
Weight
Mounting
Dimensions
Specifications
Allowable operating voltage
range
Allowable operating frequency
range
Input frequency range
85% to 110% of power supply voltage
50/60 Hz
±5
Hz
K8AK-AS1 and K8AK-AS2: DC input or AC input (45 to 65 Hz)
K8AK-AS3:
AC input (45 to 65 Hz)
K8AK-AS1 and K8AK-AS2: Continuous input at 120% of maximum input, 1 s at 150%
K8AK-AS3:
Continuous input at 120%, 30 s at 200%, and 1 s at 600% with an OMRON CT (K8AC-CT200L)
Note:
Overload capacity of primary side of CT.
±0.5%
full scale (at 25°C and 65% humidity, rated power supply voltage, DC or 50/60 Hz sine wave input)
±50
ms (at 25°C and 65% humidity, rated power supply voltage)
EN 60947-5-1
Installation environment (pollution level 2, installation category III)
EN 60947-5-1
UL 508 (Recognition), Korean Radio Waves Act (Act 10564), CSA: C22.2 No.14,
CCC: GB14048.5
20 MΩ min.
Between external terminals and case
Between power supply terminals and input terminals
Between power supply terminals and output terminals
Between input terminals and output terminals
2,000 VAC for one minute
Between external terminals and case
Between power supply terminals and input terminals
Between power supply terminals and output terminals
Between input terminals and output terminals
1,500 V power supply terminal common/normal mode
Square-wave noise of ±1
µs/100
ns pulse width with 1-ns rise time
Frequency 10 to 55 Hz, 0.35-mm single amplitude, acceleration 50 m/s
2
10 sweeps of 5 min each in X, Y, and Z directions
100 m/s
2
, 3 times each in 6 directions along 3 axes
Terminals: IP20
Overload capacity
Operating value
Operating time
Conforming
standards
Applicable
standards
EMC
Safety standards
Repeat error
Insulation resistance
Dielectric strength
Noise immunity
Vibration resistance
Shock resistance
Degree of protection
●Relationship
of Mounting Distance between K8AK-AS Relays and Input Current (Reference Values)
The following diagram shows the relationship between the mounting distances and the input current. If the relay is used with an input current that
exceeds these values, the temperature of the K8AK may rise and shorten the life of the internal components.
AS (I3 terminal)
I=1A
60
Ambient temperature [°C]
50
I=5A
40
30
20
10
I=3A
I=8A
Test method
Sample: K8AK-AS
Applied voltage: 240 VAC
Mounting distances: 0, 5, and 10 mm min.
K8AK
No.1
K8AK
No.2
K8AK
No.3
K8AK
No.4
K8AK
No.5
0
5
10
15
DIN Track
Distance between products: d
Distance between products d [mm]
3
K8AK-AS
Connections
Terminal Diagram
K8AK-AS1 100-240VAC
A
Control Output
Relay output
250 VAC, 5 A (resistive load)
30 VDC, 5 A (resistive load)
A1
I1
C
I2
A2
I3
100 mA max.
B
A
Current Input
AS1
C
500 mA max.
AS2
C
AS3
C
100 A max.
200 A max.
B
Power Supply Voltage
20 mA max.
1 A max.
5 A max.
100 to 240 VAC
A1
A2
24 VAC/DC
A1
A2
8 A max.
CT
CT
I1
I2
I3
I1
I2
I3
I1
I2
I3
(No polarity)
Relay Output
Common
11
11
12
14
12
14
Note: 1.
2.
3.
4.
5.
6.
Do not connect anything to terminals that are shaded in gray.
There is no polarity for the DC power supply input.
For the current input, you can input only from the C terminal and one other terminal.
Refer to
Setting Ranges and Wiring Connections
on the I1, I2, and I3 current input terminals.
Use the recommended ferrules if you use twisted wires.
The K8AK-AS3 is designed to be used in combination with the OMRON K8AC-CT200L Current Transformer (CT).
Wiring Example
Directly Inputting a Current
Single-phase
power supply
Using a CT
Single-phase
power supply
CT
Load
Load
Power supply
A2
voltage
A1
A1
I1
C
I2
A2
I3
Power
A2
supply voltage
A1
A1
I1
C
I2
A2
I3
Power
supply
AC/DC
Power
supply
AC/DC
11
12
14
11
12
14
Timing Charts
●Overcurrent
Operation Diagram
(Output Relay Drive Method: Normally Open)
DIP switch setting: SW3 OFF.
Power supply
voltage
Hysteresis
(−5% to 50% of operating value)
●Undercurrent
Operation Diagram
(Output Relay Drive Method: Normally Closed)
DIP switch setting: SW3 ON.
Power supply
voltage
Set value
Input
Flashing
Alarm indicator
Lit
Relay 11-14
Relay 11-12
t: Operating time (0.1 to 30 s)
t
LOCK: Startup lock time (0 to 30 s)
LOCK
Set value
Input
Alarm indicator
Relay 11-14
Relay 11-12
t
t: Operating time (0.1 to 30 s)
Flashing
Lit
Hysteresis
(5% to 50% of operating value)
4
K8AK-AS
Nomenclature
Front
Terminal block
(See notes 1 and 2.)
●Indicators
Item
Power indicator
(PWR: Green)
Relay status indicator
(RY: Yellow)
Current knob (SV)
Meaning
Lit when power is being supplied.
Lit when relay is operating.
Lit when there is an overcurrent or un-
dercurrent.
The indicator flashes to indicate the er-
ror status after the input has exceeded
the set value while the operating time
is being clocked.
Power indicator
Hysteresis knob (HYS.)
Relay status indicator
Alarm indicator
(ALM: Red)
Alarm indicator
Operating time knob (T)
●Setting
Knobs
Item
Usage
Used to set the current to 10% to 100%
of maximum setting range.
Used to set the rest value to 5% to 50%
of the operating value.
Used to set the operating time to 0.1 to
30 s.
Used to set the startup lock time to 0 to
30 s.
Startup lock time knob
(LOCK)
Current knob (SV)
Hysteresis knob (HYS.)
Operating time knob (T)
Terminal block
(See notes 1 and 2.)
Startup lock time knob
(LOCK)
Note: 1.
Use either a solid wire of 2.5 mm
2
maximum or a ferrule with
insulating sleeve for the terminal connection.
The length of the exposed current-carrying part inserted into
the terminal must be 8 mm or less to maintain dielectric
strength after connection.
For 2.5 mm
2
or
smaller solid wires
For ferrules with
an insulation sleeve.
8 mm max.
8 mm max.
Recommended ferrules
Phoenix Contact
•
Al 1,5-8BK (for AWG16)
•
Al 1-8RD (for AWG18)
•
Al 0,75-8GY (for AWG18)
2.
Tightening torque: 0.49 to 0.59 N·m
5
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