Slim-line relays monitor three-phase motor temperature, phase sequence and phase loss.

K8AK-TS relays monitor the temperature of the motor's thermal protection. K8AK-PT monitors temperature, phase sequence and phase loss for 3-phase, 3-wire motors in one unit.

  • Specially designed for internal motor monitoring: no setting required
  • Test/Reset button for confirmation of output operation
  • Reset operation: automatic or manual
  • Robust operating temperature: -20 to 60 ⁰C

  • 22.5 mm (w) body
  • External Test/reset button
  • Selectable reset feature

Specifications & ordering info

Ordering information

Rated input

Order code

Phase sequence, phase loss and temperature monitoring

100 to 240 VAC

K8AK-PT1 100-240 VAC

Temperature monitoring

K8AK-TS1 100-240 VAC




Ambient operating temperature

−20 to 60°C (with no condensation or icing)

Storage temperature

−25 to 65°C (with no condensation or icing)

Input frequency

50/60 Hz (AC power supply)

Output relays
(2 × SPDT, normally closed operation)

Resistive load

5 A at 250 VAC or at 30 VDC

Maximum contact voltage

250 VAC or 30 VDC

Maximum contact current

5 A

Maximum switching capacity

1,250 VA, 150 W

Mechanical life

10,000,000 operations

Electrical life

50,000 operations at 250 VAC or 30 VDC

Degree of protection

Terminal section: IP20

Case material

PC and ABS UL94 V-0


Approx. 150 g

Rated input voltage

3-phase, 3-wire mode: 200 to 480 VAC

Reset method

Manual reset/automatic reset (switchable)1

Operating time (T)

Phase-sequence on three-phase voltage input

0.1 s ±0.05 s

Phase loss on three-phase voltage input

0.1 s max. (when the voltage changes rapidly from 100 to 0% of rated voltage)

PTC thermistor input

0.2 s max.

Overload capacity

Continuous input: 528 V


Power (PWR): Green, PH alarm outputs (ALM): Red, TS alarm outputs (ALM): Red

Applicable standards

Conforming standards

EN 60947-5-1
Installation environment (pollution level 2, installation category III)


EN 60947-5-1

Safety standards

UL 508 (Recognition), Korean Radio Waves Act (Act 10564), CSA and CCC

Size in mm (H × W × D)

90 × 22.5 × 100

1. Manual reset method: Press the TEST/RESET button.
1. Manual reset method: Press the TEST/RESET button.

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