K8AB-PA

9

Checking Operation

With the rated input voltage applied, gradually change the

voltage to any one phase. The Unit will operate when the

difference between the maximum and minimum voltage

phases reaches or exceeds the asymmetry operating value.

Asymmetry operating value = Rated input voltage

×

Asymmetry set value (%)

Example: For monitoring mode set to three-phase three-wire

monitoring, a rated voltage of 200 V, and an operating time

of 5 s.

Note: K8AB-PA

@ output relays are normally operative.

Connection Diagram 1

How to Measure the Operating Time

Asymmetry

Change the input rapidly from a symmetric state to an

asymmetric state and measure the time until the relay

operates.

Operating Time

Adjust the slide resistor so that the voltage difference

applied to the K8AB terminals is equal to or greater than

the asymmetry operating value when the auxiliary relay

operates, as shown in connection diagram 2. Close the

switch and use the cycle counter to measure the operating

time.

Connection Diagram 2

Checking the Phase Sequence and Phase Loss

Operation

Phase Sequence Operation

Switch the wiring, as shown by the dotted lines in

connection diagram 1, to reverse the phase sequence and

check that the K8AB operates.

Phase Loss Operation

Create a phase loss for any input phase and check that the

K8AB operates.

Operating Adjustment Knobs

Use a screwdriver to turn the knobs. There is a stopper to

prevent the knob from turning any further once it has been

turned completely to the left or right. Do not force the knob

past these limits.

Load-side Phase Loss

In principle, phase loss cannot be detected on the load side

because the K8AB-PA

@ measures three-phase voltage to

determine phase loss.

Questions and Answers

Q

Alarm indicator

Asymmetry operating voltage (set value)

Contact

T1: Startup lock time (1 s or 5 s)

Flashing

L1

L2

L3

T

T: Operating time (0.1 to 30 s)

Lit

Inputs

0 to 150 V

V1

Three-phase variable

autotransformer

L1

L2

L3

3

φ

200 VAC

V2 V3

L1

L2

Q

3

φ 200 VAC

L1

L2

L3

±

C 200 V

Cycle counter

V1

V2 V3

X

X/a

X/b

L1

L2

L3

R1

R2

R1: Slide resistor

200

Ω 200 W

R2: 100

Ω 400 W

Q

Q

Q