Omron, K8AK-AS

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.

last update: April 3, 2017

Input Range

Model	*Range 1**	Connection terminal	Setting range	Input impedance	Input type	Overload capacity
K8AK-AS1	0 to 20 mA AC/DC	I1-COM	2 to 20 mA AC/DC, 10 to 100 mA AC/ DC, 50 to 500 mA AC/DC	Approx. 5 Ω	Direct input	Continuous input at 120% of maximum input 1 s at 150%
	0 to 100 mA AC/DC	I2-COM		Approx. 1 Ω	Direct input
	0 to 500 mA AC/DC	I3-COM		Approx. 0.2 Ω	Direct input
K8AK-AS2	0 to 1 A AC/DC	I1-COM	0.1 to 1 A AC/DC, 0.5 to 5 A AC/DC, 0.8 to 8 A AC/DC	Approx. 0.12 Ω	Direct input or commercially available CT
	0 to 5 A AC/DC	I2-COM		Approx. 0.02 Ω	Direct input or commercially available CT
	0 to 8 A AC/DC	I3-COM		Approx. 0.02 Ω	Direct input
K8AK-AS3	0 to 100 A AC	I2-COM	10 to 100 A AC 2, 20 to 200 A AC 2	-	OMRON CT	Continuous input at 120% with an OMRON CT (K8AC-CT200L). 30 s at 200% 1 s at 600% * CT capacity on primary side.
K8AK-AS3	0 to 200 A AC	I3-COM	10 to 100 A AC 2, 20 to 200 A AC 2	-	OMRON CT

*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	Isolated power supply	24 VAC/DC 100 to 240 VAC
Power consumption		24 VAC/DC: 2.0 VA/1.1 W max. 100 to 240 VAC: 4.6 VA max.
Operating value setting range (SV)		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
Operating value		100% operation at set value
Reset value setting range (HYS.)		5% to 50% of operating value
Reset method		Manual reset/automatic reset (switchable) Note: Manual reset: Turn OFF power supply for 1 s or longer.
Operating time setting range (T)		0.1 to 30 s
Startup lock time setting range (LOCK) Note: Enabled only for overcurrent operation.		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.
Indicators		Power (PWR): Green, Relay output (RY): Yellow, Alarm outputs (ALM): Red
Input impedance		Refer to Input Range on this page.
Output relays		One SPDT relay (NO/NC switched using DIP switch.)
Output relay ratings		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
Ambient operating temperature		-20 to 60°C (with no condensation or icing)
Storage temperature		-25 to 65°C (with no condensation or icing)
Ambient operating humidity		25% to 85% (with no condensation)
Storage humidity		25% to 85% (with no condensation)
Altitude		2,000 m max.
Terminal screw tightening torque		0.49 to 0.59 Nm
Terminal wiring method		Recommended wire Solid wire: 2.5 mm² Twisted wires: AWG16, AWG18 Note: 1. Ferrules with insulating sleeves must be used with twisted wires. Note: 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
Case color		N1.5
Case material		PC and ABS, UL 94 V-0
Weight		Approx. 150 g
Mounting		Mounts to DIN Track
Dimensions		22.5 × 90 × 100 mm (W×H×D)

Specifications

Allowable operating voltage range		85% to 110% of power supply voltage
Allowable operating frequency range		50/60 Hz ±5 Hz
Input frequency range		K8AK-AS1 and K8AK-AS2: DC input or AC input (45 to 65 Hz) K8AK-AS3: AC input (45 to 65 Hz)
Overload capacity		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.
Repeat error	Operating value	±0.5% full scale (at 25°C and 65% humidity, rated power supply voltage, DC or 50/60 Hz sine wave input)
Repeat error	Operating time	±50 ms (at 25°C and 65% humidity, rated power supply voltage)
Applicable standards	Conforming standards	EN 60947-5-1 Installation environment (pollution level 2, installation category III)
	EMC	EN 60947-5-1
	Safety standards	UL 508 (Recognition), Korean Radio Waves Act (Act 10564), CSA: C22.2 No.14, CCC: GB14048.5
Insulation resistance		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
Dielectric strength		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
Noise immunity		1,500 V power supply terminal common/normal mode Square-wave noise of ±1 μs/100 ns pulse width with 1-ns rise time
Vibration resistance		Frequency 10 to 55 Hz, 0.35-mm single amplitude 10 sweeps of 5 min each in X, Y, and Z directions
Shock resistance		100 m/s², 3 times each in 6 directions along 3 axes
Degree of protection		Terminals: IP20

Relationship of Mounting Distance between K8AK-AS Relays and Input Current (Reference Values)

AS (I3 terminal) 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.

last update: April 3, 2017

Single-phase Current Relays

K8AK-AS1
K8AK-AS2
K8AK-AS3

OMRON CT

K8AC-CT200L

Note: The OMRON Current Transformer (CT) is designed to be used with the K8AK-AS3.
Use terminals k and l for connections.
(Terminals kt and lt are not used.)

Optional Parts for DIN Track Mounting

DIN Tracks

PFP-100N
PFP-50N

TITLE	DOCUMENT TYPE	SIZE
K8AK-AS	Catalog	1354 KB