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Three-phase Voltage and Phase-sequence Phase-loss Relay


Ideal for Monitoring 3-phase Power Supplies for Industrial Facilities and Equipment. 22.5 mm (W). Two SPDT output relays


Rated input
K8AK-PM1 Three-phase, three-wire Mode: 200, 220, 230 and 240 VAC
Three-phase, four-wire Mode: 115, 127, 133 and 138 VAC
K8AK-PM2 Three-phase, three-wire Mode: 380, 400, 415 and 480 VAC
Three-phase, four-wire Mode: 220, 230, 240 and 277 VAC
Input load K8AK-PM1: Approx. 4.4 VA
K8AK-PM2: Approx. 4.4 VA
Operating value setting range
 -30% to 25% of rated input voltage
 -30% to 25% of rated input voltage
Note: The rated input voltage can be switched using the DIP switch.
Operating value 100% operation at set value
Reset value 5% of operating value (fixed)
Reset method Automatic reset
Operating time
setting range (T)
0.1 to 30 s
Phase sequence 0.1 s±0.05 s
Phase loss 0.1 s max.
Power ON lock time (LOCK) 1 s or 5 s (Switched using DIP switch.)
Indicators Power (PWR): Green, Relay output (RY): Yellow, OVER/UNDER: Red
Output relays Two SPDT relays (NC operation)
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 N·m
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.
    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)


Input frequency 50/60 Hz
Overload capacity Continuous input at 115% of maximum input, 10 s at 125% (up to 600 VAC).
Operating value ±0.5% full scale (at 25°C and an ambient humidity of 65% at the rated power supply
voltage, DC and 50/60 Hz sine wave input)
Operating time ±50 ms (at 25°C and 65% humidity, rated power supply voltage)
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: GB/T 14048.5
Insulation resistance 20 MΩ
Between all external terminals and the case
Between all input terminals and all output terminals
Dielectric strength 2,000 VAC for 1 min
Between all external terminals and the case
Between all input terminals and all 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-PM Relays and Ambient Temperature (Reference Values)

The following diagram shows the relationship between the mounting distances and the ambient temperature.
If the relay is used with an ambient temperature that exceeds these values, the temperature of the K8AK may rise and shorten the life of the internal components.

K8AK-PM Specifications 3