4
Three-phase Asymmetry and Phase-sequence Phase-loss Relay
K8AB-PA
Cat. No. N147-E1-01
Connections
■
Wiring Diagram
Voltage Asymmetry and Phase Sequence/Phase Loss Operation Diagram
Nomenclature
■
Front
Indicators
Setting Knobs
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.
The 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.
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.
Input
Output
N L1 L2 L3
N
L1
L2
L3
14
12
11
Alarm
Load
The power
supply is
shared with
the rated in-
put voltage.
Power indicator
Relay status indicator
Asymmetry rate knob
(ASY.)
Operating time knob (T)
Alarm indicator
Item
Meaning
Power indicator (PWR: Green)
Lit when power is being
supplied.
Relay status indicator (RY: Yellow) Lit when relay is operating
(normally lit).
Alarm indicator (ALM: Red)
Asymmetry voltage error
indicator
The indicator flashes to indicate
the error status after the input
has exceeded the threshold
value while the operating time is
being clocked.
Item
Usage
Asymmetry rate knob (SV) Used to set the asymmetry rate to 2%
to 22%.
Operating time knob (T)
Used to set the operating time to 0.1 to
30 s.
