J-38
Three-phase Phase-sequence Phase-loss Relay
K8AB-PM
Connections
■
Wiring Diagram
Overvoltage/Undervoltage and Phase Sequence/Phase Loss Operation Diagram
Note: 1. The K8AB-PM 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.
Nomenclature
■
Front
Indicators
Setting Knobs
L1
L3
L2
L3
L2
L1
L1
L2
L3
T
T1
T
L1
L2
L3
L1
L2
L3
Flashing
Lit
Flashing
Lit
Overvoltage alarm indicator
Undervoltage setting value
Overvoltage
setting value
Undervoltage alarm indicator
Overvoltage relay
Undervoltage relay
Input
Hysteresis: Fixed at 5%
Hysteresis: Fixed at 5%
T: Operating time (0.1 to 30 s)
T: Operating time (0.1 to 30 s)
T1: Power ON lock (1 s or 5 s)
Phase loss operation
Phase sequence operation
Flashing Flashing
Input
Undervoltage alarm indicator
Undervoltage relay
Input
Output
Output
N L1 L2 L3
N
L1
L2
L3
The power
supply is
shared with
the rated in-
put voltage.
14
12
11
24
22
21
Over-
voltage
alarm
Load
Undervoltage
alarm, phase
loss/phase se-
quence alarm
Power indicator
Relay status indicator
Overvoltage knob
(OVER)
Undervoltage knob
(UNDER)
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)
Overvoltage:
Red
Lit for overvoltage.
The indicator flashes to indicate the error
status after the overvoltage has exceeded
the threshold value while the operating
time is being clocked.
Undervoltage:
Red
• Lit for an undervoltage or phase loss.
The indicator flashes to indicate the
error status after the undervoltage has
exceeded the threshold value while the
operating time is being clocked.
• Lit for phase sequence error.
Item
Usage
Overvoltage knob
(OVER)
Used to set the voltage to
−
30% to 25% of
the rated input voltage.
Undervoltage knob
(UNDER)
Used to set the voltage to
−
30% to 25% of
the rated input voltage.
Operating time knob (T)
Used to set the operating time to 0.1 to
30 s.
