Omron K2CU Manual page 4

K2CU
K2CU-F Series
When power is supplied to the heater (when the contactor is ON), a
current flows through the wires to the heater elements. At the same
time, a voltage is imposed on the power circuit of the K2CU-F.
The current flowing to the heater wires is detected by the detector
sections through each Current Transformer (CT) incorporated by
the K2CU-F.
The current signals transmitted by the two CTs are sent to the cur-
rent-voltage converters, smoothing circuits, and comparators as
shown in the diagram.
Power source
Contactor
CT
1
Current-
voltage
converter
CT
2
Current-
voltage
converter
Note: The dotted lines indicate the line conductors passing through the windows of the current transformers.
Heater elements
K2CU-P Series
The K2CU-P operates basically in the same way as the K2CU-F.
The comparator compares external current signals and the refer-
ence value and outputs the result of the comparison to the output
circuit.
Power source
Contactor
1
2
Heater elements
4
Smoothing Comparator
circuit
Smoothing Comparator
circuit
CT
Current- Smoothing
voltage circuit
converter
The signal generated by the reference voltage generator is sent to
the setting circuit to provide a reference value. The reference value
is sent to the comparators. Each comparator compares its heater
element current input and the reference value. If the input is lower
than the reference value, a signal is sent to the output circuit.
There are two detector sections operating independently. If either of
the input signals from the CTs is lower than the reference value, the
output relay and alarm indicator will be activated.
The K2CU-F incorporates a voltage fluctuation compensation func-
tion which automatically corrects the reference value if the supply
voltage fluctuates.
Setting Reference
circuit voltage
generator
To each circuit
Output
circuit
Output relay
Reference Power
voltage circuit
generator
Setting
To each circuit
circuit
Comparator Output
circuit
S1 S2
Power
circuit
b1
X/c
a1
Buzzer
X CM1
BZ
Alarm indicator
200/220 V 100/110 V
6 7 8
5
X/c
4
X
3
Output relay
Alarm indicator
K2CU
0 V
Buzzer
BZ