Heater Element Burnout Detector
K2CU
Accurate Detection of Heater Element
Burnout Regardless of Heater
Capacities
Accurately detects a burned heater element or
elements incorporated by a molding machine or
packing machine and outputs an alarm signal.
Precisely singles out the burned element even if
one heater element among several heater
elements has been burned out.
Applicable to small- to large-capacity heater
elements.
All K2CU-F large-capacity, built-in current transformer models work with both single-phase and
three-phase heaters.
Voltage fluctuation compensation function eliminates false alarms due to variations in the supply
voltage.
Ordering Information
K2CU-FjjA-jGS Model with Gate Input Terminals
Control
supply voltage
4 to 10 A 8 to 20 A
100 V
AC W
ith voltage fluctuation
1
10 V
AC compensation K2CU-F10A-DGS K2CU-F20A-DGS K2CU-F40A-DGS K2CU-F80A-DGS
200 V
AC K2CU-F10A-EGS K2CU-F20A-EGS K2CU-F40A-EGS K2CU-F80A-EGS
220 V
AC K2CU-F10A-FGS K2CU-F20A-FGS K2CU-F40A-FGS K2CU-F80A-FGS
K2CU-F10A-CGS K2CU-F20A-CGS K2CU-F40A-CGS K2CU-F80A-CGS
Operating current
16 to 40 A 32 to 80 A
K2CU-F Large-capacity, Built-in Current Transformer Models
Control
supply voltage
4 to 10 A 8 to 20 A
100 V
AC W
ith voltage fluctuation
1
10 V
AC compensation K2CU-F10A-D K2CU-F20A-D K2CU-F40A-D K2CU-F80A-D
200 V
AC K2CU-F10A-E K2CU-F20A-E K2CU-F40A-E K2CU-F80A-E
220 V
AC K2CU-F10A-F K2CU-F20A-F K2CU-F40A-F K2CU-F80A-F
K2CU-F10A-C K2CU-F20A-C K2CU-F40A-C K2CU-F80A-C
Operating current
16 to 40 A 32 to 80 A
K2CU-P Small-capacity, Plug-in Models
Control
100/
200 V
110/
220 V
supply voltage
W
ith voltage fluctuation
AC
compensation
W
ithout voltage
fluctuation compensation
W
ith voltage fluctuation
AC
compensation
W
ithout voltage
fluctuation compensation
0.25 to 0.5 A
K2CU-P0.5A-A K2CU-P1A-A K2CU-P2A-A K2CU-P4A-A
--- K2CU-P1-A K2CU-P2-A K2CU-P4-A
K2CU-P0.5A-B K2CU-P1A-B K2CU-P2A-B K2CU-P4A-B
--- K2CU-P1-B K2CU-P2-B K2CU-P4-B
Operating current
0.5 to 1 A
1 to 2 A 2 to 4 A
1
K2CU
Specifications
Ratings
Item K2CU-F K2CU-P
Control
supply voltage
Rated frequency
Carry current
Operating voltage range
V
oltage fluctuation compensation
range
Operating current
Releasing current
Operate time
Gate input voltage range (for
models with gate input terminals)
Control output
Power consumption
100, 1
10, 200, 220 V
50/60 Hz
1.25 times as large as each model’
maximum operating current
85% to 1
85% to 1
4 to 10 A, 8 to 20 A, 16 to 40 A, 32 to 80 A
(continuously variable)
105% max. of operating current
0.5 s max. (when current changes from 150% to 0%)
5 to 30 VDC
2 A at 220 V
Input: 0.5 V
Power supply: 5 V
10% of control supply voltage
10% of control supply voltage
A max.
AC
AC, SPDT (cosφ
A max.
= 0.4)
100/200, 1
s
2.5 A for K2CU-P0.5A-A/-B;
5 A
85% to 1
(applicable only on models with voltage
fluctuation compensation)
0.25 to 0.5 A, 0.5 to 1 A, 1 to 2 A, 2 to 4 A
(continuously variable)
1
10% max. of operating current
---
Input: 1 V
Power supply: 4 V
10/220 V
10% of control supply voltage
A max.
AC
A max.
K2CU
Characteristics
Setting
accuracy
Repeat accuracy
Influence of temperature
Influence of voltage
Influence of frequency
Insulation resistance
Dielectric strength
Overcurrent
V
ibration resistance
Shock resistance
Ambient temperature
Ambient humidity
Weight
Note: The
logical value is an operating value within a range of 0.85 to 1.1 with a voltage fluctuation of 85% to 1
control
supply voltage measured as 1.
±
7% max.
±
3% max.
±
10% max. (at 20
Models without voltage fluctuation compensation:
±
3% max. of the value measured at the control supply voltage, on condition that the voltage
fluctuation is 85% to 1
Models with voltage fluctuation compensation:
±
5% max. of the logical value, on condition that the voltage fluctuation is 85% to 1
control supply voltage. (see note)
±
3% max. (at ±5% of rated frequency)
10 MΩ min. (at 500 VDC) between electric circuits and mounting panel
2,000 V
AC, 50/60 Hz for 1 min between electric circuits and mounting panel
20 times of max. set value of operating current for 2 s
Destruction: 16.7 Hz, 1-mm double amplitude for 10 min each in X, Y
Destruction: 100 m/s2 (approx. 10G)
Operating: –10°C to 55°C (with no icing)
Operating: 45% to 85%
K2CU-F: approx. 390 g; K2CU-P: approx. 300 g
°C±30°C)
10% of the control supply voltage
10% of the
, and Z directions
10%, based on the value at the
2
K2CU
Operation
K2CU-F A- GS
When
power is supplied to the heater (when the SSR is ON), a cur
rent flows through the wires to the heater elements. At the same
time, a voltage is imposed on the gate circuit and the
K2CU-FjjAjGS begins monitoring the current flowing through
the
heater wires.
The current flowing to the heater wires is detected by the detector
sections through each Current Transformer (CT) incorporated by
the K2CU-FjjA-jGS.
The
current signals transmitted by the two CT
rent-voltage converters, smoothing circuits, and comparators as
shown
in the diagram.
Power source
Series
s are sent to the cur
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
the
input signals from the CT
output
detector sections operating independently
s is lower than the reference value, the
relay and alarm indicator will be activated.
The K2CU-FjjA-jGS incorporates a voltage fluctuation com-
-
pensation
if
the supply voltage fluctuates.
function which automatically corrects the reference value
K2CU
. If either of
SSR DC
CT
1
CT
2
Heater elements
Currentvoltage
converter
Currentvoltage
converter
Note: 1. The
Smoothing
circuit
Smoothing
circuit
Gate
circuit
Comparator
Comparator
dotted lines indicate the line conductors passing through the windows of the current transformers.
2.
The current flowing into the gate circuit (between G+ and G–) is as follows:
Approximately 1.4 mA at 5 VDC
Approximately 3.4 mA at 12 VDC
Approximately 6.7 mA at 24 VDC
3
When using a K2CU which has the model number suf
terminals), the control output of the temperature controller must be a voltage output type.
Temperature
controller
Setting
circuit
Reference
voltage
generator
Output
circuit
Power
circuit
To each circuit
Output relay
X CM1
Alarm indicator
fix ”GS” (a model that incorporates gate input
S2S1G–G+
b1
X/c
a1
Buzzer
BZ
3
K2CU
K2CU
K2CU-F
When
Series
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 CT
s are sent to the cur
rent-voltage converters, smoothing circuits, and comparators as
shown
in the diagram.
Power source
Contactor
CT
1
Currentvoltage
converter
CT
2
Currentvoltage
converter
Smoothing
circuit
Smoothing
circuit
Comparator
Comparator
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
the
input signals from the CT
output
The
K2CU-F incorporates a voltage
detector sections operating independently
s is lower than the reference value, the
relay and alarm indicator will be activated.
fluctuation compensation func
tion which automatically corrects the reference value if the supply
voltage
fluctuates.
S2S1
Setting
circuit
Reference
voltage
generator
Output
circuit
Power
circuit
To each circuit
Output relay
b1
X/c
a1
X CM1
Buzzer
BZ
. If either of
-
Note: The
Heater elements
K2CU-P
The
Series
K2CU-P operates basically in the same way as the K2CU-F
dotted lines indicate the line conductors passing through the windows of the current transformers.
The comparator compares external current signals and the reference value and outputs the result of the comparison to the output
circuit.
Power source
Contactor
1
CT
Currentvoltage
2
converter
Smoothing
circuit
.
Setting
circuit
Reference
voltage
generator
To each circuit
Comparator
Alarm indicator
200/220 V 100/110 V 0 V
6
Power
circuit
Output
circuit
X
Output relay
X/c
Alarm indicator
87
5
4
Buzzer
3
BZ
Heater elements
4
K2CU
K2CU
Setting of Operating Current
Use the potentiometer on the front panel to set the operating current.
the knob to set the desired current value at which the
Rotate
Burnout
Detector should operate. Do
minimum
positions.
not exceed the maximum and
Heater
The K2CU-F’s scale is divided into 12 graduations including subgraduations
The
are
knobs of
and the K2CU-P’
the K2CU-F and K2CU-P as shown in the illustrations
s scale is divided into 5 graduations.
set to 32 A and 0.7 A respectively
.
Knob
Heater Connection and Current
The
following table shows the dif
heater
elements under normal and abnormal conditions.
Phase
Single phase
ferent connections possible. The formula under each illustration indicates the electrical current value of
Normal condition
5 A
The
set operating current is defined as the mean value
of the heater
current under normal operating conditions and the heater current
under
a burnout or abnormal condition.
Set value =
Normal current + abnormal current
2
Red point
(indicates the set value)
the
Abnormal condition
0 A
Three
phase
Delta
network
Star
network
V
network
Note: Values
200 V
200 V
200 V
200 V
200 V
200 V
200 V
200 V
200 V
200 V
(5 A x = 8.7 A)
1 kW
5 A
8.7 A
8.7 A
8.7 A
(5 A x )
2.9 A
2.9 A
2.9 A
1
(5 A x )
5 A
8.7 A
5 A
3
1 kW
1 kW
3
1 kW
1 kW
3
1 kW
1 kW
in this table are correct when a 200 V
200 V
0 A
1 kW
1 kW
7.5 A
7.5 A
(5 A x x )
3
2.5 A
2.5 A
1
3
2.5 A
2.5 A
3
2
(5A x 1/2)
(5 A x x )
3
2
5 A
8.7 A
5 A
(5 A x x )
2.5 A
2.5 A
(5 A x x )
5 A
5 A
(5A x 1)
AC, 1 kW heater is used on a single-phase or three-phase current.
1
3
3
1
3
2
3
5
K2CU
K2CU
Operation Check
K2CU-F A- GS
The
operation of the heater burnout detector can be easily
as
follows:
In a Single-phase Circuit
Set
the operating current to be 0.6 to 0.55 times the heater current.
Close the SW2 with switch SW1 turned on. Confirm that the alarm
indicator remains of
of
f SW1 and confirm that the alarm indicator comes on, and that
Turn
the
output relay operates.
f.
SSR
G+
G–
S1
S2
K2CU-F
SW
2
checked
In a Three-phase, Star Network
Set the operating current to be 0.9 times the heater current.
Close the SW2 with switch SW1 turned on. Confirm that the alarm
indicator remains of
Turn
of
f SW1 and confirm that the alarm indicator comes on, and that
the
output relay operates.
G+
G–
f.
SW
2
SSR
S1
S2
K2CU-F
SW
1
SW
1
Heater
In a Three-phase, Delta Network
Set the operating current to be 0.6 times the heater current.
Close
the SW3 with switches SW1 and SW2 turned
the
alarm indicator remains of
Turn
of
f SW2 and confirm that the alarm indicator comes on, and that
the
output relay operates.
Turn
on SW1 set the operating current to be 0.9 times the heater cur
f.
on. Confirm that
rent, and confirm that the alarm indicator goes off and the output
relay
releases.
Turn
of
f SW1 and confirm that the alarm indicator comes on, and that
the
output relay operates.
SW
3
SSR
G+
G–
S1
S2
K2CU-F
SW
1
Heater
-
SW
Heater
2
6
K2CU
K2CU
In a Three-phase, V Network 1
Set
the operating current to be 0.3 to 0.35 times the heater current.
Close the SW2 with switch SW1 turned on. Confirm that the alarm
indicator remains of
f.
Turn off SW1 and confirm that the alarm indicator comes on, and
that
the output relay operates.
SW
2
SSR
G+
G–
S1
S2
K2CU-F
SW
1
In a Three-phase, V Network 2
Set
the operating current to be 0.6 times the heater current (of
the
phase connected between terminals 1 and 2, or the one passed
through
the window
heater
burnout detector).
of the window-type Current T
ransformer of the
Close the SW2 with switch SW1 turned on. Confirm that the alarm
indicator remains of
f.
Turn off SW1 and confirm that the alarm indicator comes on, and
the output relay operates.
that
SW
2
SSR
G+
G–
S1
S2
SW
1
K2CU-F
Heater
K2CU-F, K2CU-P
The
operation of the heater burnout detector can be easily
as
follows:
In a Single-phase Circuit
Set
the operating current to be 0.55 to 0.6 times the heater current.
Contactor
S1
S2
K2CU-F
checked
Heater
Close the contactor with switch SW1 turned on. Confirm that the
alarm
indicator remains of
of
f SW1 and confirm that the alarm indicator comes on, and that
Turn
the
output relay operates.
f.
Contactor
1
2
K2CU-P
SW
1
Heater
SW
1
Heater
7
K2CU
K2CU
In a Three-phase, Delta Network
Set the operating current to be 0.6 times the heater current.
Close
the contactor with switches SW1 and SW2 turned on. Confirm
that
the alarm indicator remains of
Turn
of
f SW2 and confirm that the alarm indicator comes on, and that
the
output relay operates.
Turn
on SW1 set the operating current to be 0.9 times the heater cur
f.
rent, and confirm that the alarm indicator goes off and the output
relay
releases.
Turn
of
f SW1 and confirm that the alarm indicator comes on, and that
the
output relay operates.
Contactor
S1
S2
K2CU-F
SW
1
SW
2
Heater
In a Three-phase, Star Network
Set the operating current to be 0.9 times the heater current.
Close the contactor with switch SW1 turned on. Confirm that the
alarm
indicator remains of
Turn
of
f SW1 and confirm that the alarm indicator comes on, and that
the
output relay operates.
f.
Contactor
In a Three-phase, V Network 1
Set
the operating current to be 0.3 to 0.35 times the heater current.
Close the contactor with switch SW1 turned on. Confirm that the
alarm
indicator remains of
f.
Turn off SW1 and confirm that the alarm indicator comes on, and
that
the output relay operates.
-
Contactor
S1
S2
K2CU-F
SW
1
Heater
In a Three-phase, V Network 2
Set
the operating current to be 0.6 times the heater current (of
phase connected between terminals 1 and 2, or the one passed
through
the window
heater
burnout detector).
of the window-type Current T
Close the contactor with switch SW1 turned on. Confirm that the
alarm
indicator remains of
f.
Turn off SW1 and confirm that the alarm indicator comes on, and
that
the output relay operates.
K2CU-P
Contactor
the
ransformer of the
S1
S2
SW
1
Heater
SW
K2CU-F
1
Heater
1
2
K2CU-P
8
K2CU
K2CU-F
Contactor
S1
S2
K2CU-F
SW
1
Heater
Test Circuit
To
check the operation in detail, use the following circuit.
K2CU-F K2CU-P
The dotted lines indicate the line conductor passing through the round
window of the current transformer.
Switch
K2CU
Switch
S1
S2
R
Slidac
SW
1
Dimensions
Note:
All units are in millimeters unless otherwise indicated.
K2CU-P
3.5
7291
b1
CM1
a1
K2CU-F
Note: Determine
7
R
Slidac
8
1
2
the value of R according to the specifications
6
5
4
3
K2CU-P
of the K2CU to be used. The dotted line indicates the
connection at a supply voltage of 100 or 1
10 V
AC.
Connecting Socket
5
K2CU-P
108
60
89
7
8.5
8PFA1
9
K2CU
K2CU
K2CU-F
Installation
Mounting
Two, 6-dia. or M5
mounting holes
102
Holes
111
102 90
Note: 1. Install
6
Eight,
M3.5
terminal
screws
Potentiometer
knob
Alarm
indicator
60
6-dia. mounting
hole
the K2CU-F on a flat surface.
2.
When solderless terminal lugs are
desired, use ones having an outer
diameter of 6.5 mm maximum.
108
95
20
6.5
mm max.
6.5 mm max.
Two, 20-dia.
holes
33
External Connections
K2CU-F A- GS
Single-phase
G+
G–
S1
S2
K2CU-F
Heater
Power
source
SSR
Heater
Temperature
controller
b1
CM1
a1
Temperature
sensor
Three-phase Heater
Power
source
Temperature
SSR
Heater
controller
b1
CM1
a1
Temperature
sensor
Control
voltage
Y/a
YBZL
Control
voltage
G+
G–
Y/a
YBZL
S1
S2
K2CU-F
10
K2CU
K2CU-F
Single-phase
Heater
Power
source
Three-phase Heater
Power
source
K2CU
Temperature
controller
Contactor
S1
S2
K2CU-F
Heater
Temperature
sensor
Three-phase, V-connected Heater
CM1
a1
Temperature
Control
contact
Y/a
YBZL
W
ith External Current T
Contactor
S1
S2
K2CU-F
Power
source
controller
Temperature
sensor
Heater
ransformer
b1
CM1
al
Control
contact
Y/a
YBZL
S1
S2
K2CU-F
Heater
b1
CM1
al
CT
jA/SA
Heater
CT
jA/SA
Note:
K2CU-F10A-j
b1
S1
S2
CM1
al
Pass two out of the three line conductors
through the current transformers of the
heater burnout detector twice as shown.
11
K2CU
K2CU-P Small-capacity, Plug-in Models
Small-capacity
Heater
W
ith External Current T
K2CU
ransformer
Power
source
Temperature
controller
Temperature
sensor
Heater
Note: 1. The
passing
2. Y:
BZ:
L:
3. To
of
Power
source
Temperature
controller
Contactor
Temperature
sensor
7
8
1
2
K2CU-P
7
8
1
2
K2CU-P
Control
contact
6
5
4
Y/a
3
YBZL
CT
jA/5 A
Heater
dotted lines which pass through the heater burnout detector indicate the line conductor
through the round “window” of the window-type Current T
ransformer.
External relay for self-holding circuit
Alarm buzzer
Alarm indicator
use an 100 (1
10) V
AC control power supply with K2CU-P
, connect
it to terminal 7 instead
6.
Control
contact
6
5
4
Y/a
3
YBZL
Precautions
K2CU-F A- GS
Use
the K2CU-F
tion with a temperature controller that has PID
cuitry to control the heater temperature, in which case, the heater
element(s)
K2CU-F
When
a single-phase heater is used, pass the two lines through the
openings of the heater burnout detector
er is used, pass two (phases) of the three lines through the
ings.
In either case, if only one line passes through, an alarm signal
will
always be produced.
With three-phase
power supply
jjA-j
GS (with
gate input terminals) in combina
with feed-forward cir
must be turned ON or OFF for 0.1 s or longer
. When a three-phase heat
With single-phase
power supply
Heater
.
open
Heater
Pass the lines through the
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
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
openings only once. If they are passed
times the lines should be passed by the fol
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 secondary
circuit of the transformer to open, which is very
-
-
-
dangerous.
12
K2CU
K2CU
General
Refer to “
nal CTs.
When a temperature controller is used in combination with the
K2CU (except for the K2CU-FjjA-jGS), the heater element(s)
must
ment(s)
The
cuit,
Mounting
Securely mount the K2CU as horizontally as possible although
there
Operating Current Setting when Several Heaters are Used
The
when
out.
a
External Connections
be turned ON or OFF for 1
can be
turned ON for 0.5 s according to the specifications).
K2CU
cannot be used with a phase-control circuit, inverter cir
” before using the K2CU with exter
s or longer (although the heater ele
frequency-count circuit, cycle-control unit, or a motor load.
is no particular limitation of mounting directions.
following
table shows relative values of changes in the current
any one of several heaters
connected in parallel has burned
The current value under normal condition is 1. Use this table as
guideline in determining the operating current.
Connection
I
I
of heater = n
No.
No.
of heater
per phase = n
Current
in burned-out phase
Current
in other phases
Connection
Solderless-type terminal must be connected to the terminals se-
curely.
the terminals correctly by referring to the external connections.
Wire
The
terminals have no polarity
the
-
100-V (or 1
220-V)
The control power source for the K2CU (except for the
K2CU-FjjA-jGS)
10-V) terminals and 200 (or 220) V to the 200-V
terminals of the K2CU-P or the K2CU-P may malfunction.
must
. Be sure to connect 100 (or 1
be supplied from the load side via a con
tactor.
sure
to impose a voltage between the 0-V terminal and 100-V (or
Be
110-V)
terminal or the 0-V terminal and 200-V (or 220-V) terminal of
the K2CU-P
, otherwise the K2CU-P will not operate.
n = 1 n = 2 n = 3 n = 4 n = 5
0 0.5 0.67 0.75 0.8
0 0.6 0.75 0.82 0.86
0.87 0.92 0.95 0.96 0.97
10) V to
(or
-
Note: 1.
I
No.
of heater
per phase = n
Current in burned-out phase
Current
in other phases
0.58 0.77 0.84 0.88 0.91
1 1 1 1 1
This table shows the respective change rates in current when any one of several heaters connected in parallel has burned out.
2.
The current value under the normal condition is 1.
3. The
values in this table are logical values. Actually
ers).
It is therefore recommended to test the actual current values and the load condition before determining the operating current,
especially
when the current under the normal condition and that under an abnormal condition do not significantly dif
, these values may vary slightly because of
influence of unbalanced loads (heat
fer.
-
13
K2CU
K2CU
ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.
To
convert millimeters into inches, multiply by 0.03937. T
o convert grams into ounces, multiply by 0.03527.
Cat. No. N39–E1–2 In the interest of product improvement, specifications are subject to change without notice.
OMRON Corporation
Measuring & Supervisory Controls Division
29th Fl., Crystal T
1–2–27, Shiromi, Chuo-ku,
Osaka 540 Japan
Phone: 06-949-6014 Fax: 06-949-6028
14
ower Bldg.
Printed
in Japan
0393–1M (0393)
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