Omron K2CU Manual page 12

K2CU
K2CU-P Small-capacity, Plug-in Models
Small-capacity Heater
Power
source
Temperature
Control
controller
contact
7
8
1
2
K2CU-P
Temperature
sensor
Heater
Note: 1. The dotted lines which pass through the heater burnout detector indicate the line conductor
passing through the round "window" of the window-type Current Transformer.
2. Y: External relay for self-holding circuit
BZ: Alarm buzzer
L: Alarm indicator
3. To use an 100 (110) VAC control power supply with K2CU-P, connect it to terminal 7 instead
of 6.
Precautions
K2CU-F A- GS
Use the K2CU-FjjA-jGS (with gate input terminals) in combina-
tion with a temperature controller that has PID with feed-forward cir-
cuitry to control the heater temperature, in which case, the heater
element(s) must be turned ON or OFF for 0.1 s or longer.
K2CU-F
When a single-phase heater is used, pass the two lines through the
openings of the heater burnout detector. When a three-phase heat-
er is used, pass two (phases) of the three lines through the open-
ings. In either case, if only one line passes through, an alarm signal
will always be produced.
With three-phase
power supply
12
6
5
4
Y/a
3
L BZ Y
With single-phase
power supply
Heater
Heater
With External Current Transformer
Power
source
Temperature
controller
Contactor
7
8
CT
jA/5 A
1
2
Temperature
sensor
Heater
Pass the lines through the openings only once. If they are passed
more than once, the actual operating current will be less than the set
current. The lines can be passed in either direction.
To use the heater burnout detector at a current less than the current
range that can be set, the lines must be passed more than once. De-
termine the number of times the lines should be passed by the fol-
lowing equation:
(Operating current) x n = Current setting range
where,
n: number of times the lines loop through the window
All K2CU-F models incorporate a voltage fluctuation compensation
function.
K2CU-P
The K2CU-P can be used only in single-phase circuits.
Do not pull out the K2CU-P from the socket when the K2CU-P is en-
ergized. Especially when using it in combination with a Current
Transformer commercially available, this practice causes the sec-
ondary circuit of the transformer to open, which is very dangerous.
Control
contact
6
5
4
3
L BZ
K2CU-P
K2CU
Y/a
Y