K8AB-PW

9

Checking Operation

Overvoltage

Gradually increase the input from 80% of the setting.

The input value will equal the operating value when the

input exceeds the setting and the alarm indicator starts

flashing. Operation can be checked by the relay output that

will start after the operating time has passed.

Undervoltage

Gradually decrease the input from 120% of the setting and

check the operation using the same method as for

overvoltage.

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-PW

@ output relays are normally operative.

Connection Diagram

How to Measure the Operating Time

Overvoltage

Change the input suddenly from 0% to 120% of the set

value and measure the time until the Unit operates.

Undervoltage

Change the input suddenly from 120% to 0% of the set

value and measure the time until the Unit operates.

Operating Time

Adjust the slide resistor so that the voltage applied to the

K8AB terminals is 120% of the overvoltage set value or

80% of the undervoltage set value when the auxiliary relay

operates in a test circuit. Close the switch and use the

cycle counter to measure the operating time.

Connection Diagram

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.

Overvoltage Detection When Only One Phase Exceeds

the Overvoltage Threshold

The K8AB monitors each of the three-phase voltages. This

means an overvoltage is detected if even only one phase

exceeds the threshold value. The same applies to

undervoltages.

Questions and Answers

Q

Set value

Input voltage

Alarm indicator

Relay output

Flashing

Lit

5 s

0 to 150 V

V1

Three-phase

variable autotransformer

L1

L2

L3

3

φ,

200 VAC

V2 V3

L1

L2

L3

Overvoltage

Undervoltage

Q

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

3

φ,

200 VAC

Q

Q

In the interest of product improvement, specifications are subject to change without notice.

ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.

To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.