K8AB-PA

5

Connections

■ Wiring Diagram

Voltage Asymmetry and Phase Sequence/Phase Loss Operation Diagram

Operation Indicators

Note: The indicator will flash once per second after a phase loss is

detected and once per 0.5 second during the detection time.

L1

L3

L2

L3

L2

L1

L1

L2

L3

T

T1

L1

L2

L3

L1

L2

L3

Relay

Asymmetry operation voltage (set value)

Input

Alarm indicator

Flashing

Lit

T: Operating time (0.1 to 30 s)

T1: Power ON lock (1 s or 5 s)

Phase loss operation

Phase sequence operation

Input

Relay

Alarm indicator

Note: 1. K8AB-PA output relay is normally operative.

2. The power ON lock prevents unnecessary alarms from being generated during

the instable period when the power is first turned on. There is no relay output

during timer operation.

3. Phase loss is detected by L1, L2, and L3 voltage drops.

A phase loss will exist if any of the phases drops below 60% of the rated input.

4. L1 and L2 function both as the power supply terminals and as input terminals.

If the voltage drops dramatically, then the Relay will not operate due to an

undervoltage.

5. Motor load phase loss cannot be detected during operation.

6. Phase loss is detected based on voltage, so phase loss cannot be detected on

the load side.

Flashing Flashing

Calculating the Asymmetry Operating Voltage

Asymmetry operation condition = (Highest voltage

− Lowest voltage) > Asymmetry operating voltage

Asymmetry operating voltage = Rated input voltage (V)

× Asymmetry set value (%)

Note: The rated input voltage is selected and set with the DIP switch.

Item

Display

Contact

operation

Ry_LED

Alarm_LED Alarm_LED

Asymmetry OFF

ON

OFF

Phase loss

OFF

ON

OFF

Reversed

phase

OFF

Flashing

(See note.)

OFF

Correct

phase

ON

OFF

ON

Load

Voltage input

Signal output

14

12

L1

L2

L3

11

L1

NL2 L3

Relay signal

output

N