Datasheet

K8AK-PM
8
Checking Operation
Overvoltages
Gradually increase the input from 80% of the set value.
The input value will equal the operating value when the input
exceeds the set value 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 set value 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: K8AK-PM@ output relays are normally operative.
Connection Diagram 1
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
K8AK terminals is 120% of the set value (for overvoltage
detection) and 80% of the set value (for undervoltage
detection) 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
Switch the wiring, as shown by the dotted lines in connection
diagram 1, to reverse the phase sequence and check that the
K8AK operates.
Phase loss
Create a phase loss for any input phase and check that the
K8AK operates.
Questions and Answers
Q
Operating set value
Input voltage
Alarm indicator
Relay output
Flashing
Lit
5 s
0 to 150 V
V1
Three-phase variable
autotransformer
Overvoltage
Undervoltage
L1
L2
L3
3φ,
200 VAC
V2 V3
L1
L2
L3
Q
3φ, 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