Questions And Answers - Omron K8DT-PM Manual

Questions and Answers

Q
Checking Operation
Overvoltage
Gradually increase the input from 80% of the set value. The
input 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 an
overvoltage.
Example: Monitoring Mode for Rated Voltage of 200 V and an Operating
Time Setting of 5 s
Operating set value
Input voltage
Alarm indicator
Contact output or
transistor output
Connection Diagram 1
3-phase,
200 VAC
L1
L2
L3
Flashing Lit
5 s
L1
V1
L2
V2 V3
L3
0 to 150 V
3-phase variable autotransformer
Q
How to Measure the Operating Time
Overvoltage
Change the input suddenly from 70% to 120% of the set value
and measure the time until the Unit operates.
Undervoltage
Change the input suddenly from 120% to 70% 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
K8DT terminals is 120% of the set value for overvoltage
detection or 80% of the set value for undervoltage detection
when the auxiliary relay in connection diagram 2 operates.
Close the switch and use a cycle counter to measure the
operating time.
Connection Diagram 2
3-phase, 200 VAC
L1
X/a
X
L2
L3
± C 200 V
Cycle counter
Checking the Phase Sequence and Phase Loss
Q
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
K8DT operates.
Phase loss
Create a phase loss for any input phase and check that the
K8DT operates.
K8DT-PM
L1
V1
L2
V2 V3
R1
X/b
L3
R2
R1: Sliding resistor, 200 Ω, 200 W
R2: 100 Ω, 400 W
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