Omron K8AC-H Series User manual

CSM_K8AC-H_DS_E_5_1
1
Digital Heater Element Burnout Detector
K8AC-H
A high-precision Heater Element Burnout
Detector compatible with a wide-range of
heater control methods.
• Compatible with contactor, SSR, cyclic control, and phase
control methods.
• Compatible with a wide range of heater capacities, from 0.200 to
200.0 A AC (range covered by 3 models)
• Voltage fluctuation compensation function enables accurate
heater burnout detection, because power supply voltage
fluctuations resulting in heater current fluctuation will not cause
faulty outputs.
• Detects burnouts for even one heater when using multiple
heaters.
• If the gate function is disabled, the gate input can be used as an
undercurrent/overcurrent relay or for motor or lamp loads (2
circuits).
•CEMarking.
• Contributes to preventative maintenance for heater burnout.
Note: Consult with your OMRON representative before using phase and
cyclic control under the following conditions.
•Using multiple heaters with different heater capacities
•Using heaters with varying heater resistance (e.g., halogen
heaters)
Features
Compatible with Many Heater Control
Methods
The K8AC-H detects burnouts for cyclic and phase control heaters,
which could not be detected by the K2CU.
One Digital Heater Element Burnout Detector can handle single-
phase or three-phase heaters.
Applicable to Wide Current Range
Current can be measured between 0.200 and 200.0 A using an
external current transformer.
Monitors Heater Current
The heater current can be checked on the main display. Error status,
such as that for heater burnout alarms, can also be displayed on the
character display.
Voltage Fluctuation Compensation
Function
The voltage fluctuation compensation function enables accurate
heater burnout detection, because power supply voltage fluctuations
resulting in heater current fluctuation will not cause faulty outputs.
This function is required when detecting minor current fluctuations.
High-precision Heater Burnout
Detection
Digital settings enable high-precision heater burnout detection.
High-precision threshold value setting is possible using current
measurement value display.
Type ON/OFF control
(connector/SSR)
Cyclic
control
Phase
control
Item K8AC-H@@C@-FLK K8AC-H@@P@-FLK
Single-phase heater {{{{
Three-phase heater {{{{
Model K8AC-H11@K8AC-H12@K8AC-H13@
Item
Current
measurement range 0.200 to 2.200 A AC 2.00 to 22.00 A AC 20.0 to 200.0 A AC
Appropriate Current
Transformer model K8AC-CT20S
K8AC-CT20L
K8AC-CT20S
K8AC-CT20L
K8AC-CT200
K8AC-CT200L
Main display
Measurement values
·Heater current
·Power supply voltage
Error display
·Heater burnout detection
·Overcurrent detection
·SSR short circuit detection
·SSR open circuit detection

K8AC-H
2
SSR Short Circuit Detection
Quickly detects control failures caused by SSR short circuits.
Useful for preventing shipping of faulty products and for improving
productivity.
Detects Overcurrents in Heater Circuits
Detects overcurrents from heater layer shorts and outputs an alarm.
Useful for preventing SSR deterioration caused by overcurrents.
RS-485 Communications
Measurement data, such as the present heater current, maximum/
minimum heater current, and power supply voltage, can be read
using RS-485 communications.
The current when the heater burned out and the total operating time
are recorded in memory, and this data can be used for preventative
equipment maintenance. (This data can be checked on the main
display.)
CE Marking
Compact Unit
(35 ×90 ×100 mm (W ×H ×D))
Problems with Current Heater Element
Burnout Detectors
•K2CU Heater Element Burnout Detectors could not detect burnouts
with cyclic or phase control heaters (performed unnecessary
operations). Generally, heater burnouts could not be detected even
by the heater burnout detection function of power regulators (phase
control devices) when multiple heaters were connected. Also,
burnout detection was not accurate when temperature controller
outputs were small.
•Power voltage fluctuations in the heater circuit caused current
fluctuations. Without a voltage fluctuation compensation function,
voltage fluctuations cause unnecessary operation.
•The K2CU has a narrow rated current range and cannot detect
minute current fluctuations when multiple heaters are detected due
to the low resolution.
Differences from Other Current Heater
Element Burnout Detection Functions
: Can detect with high precision {: Can detect ×: Cannot detect
Model Number Structure
■Model Number Legend
1. Basic Model
K8AC-H: Digital Heater Element Burnout Detector
2. Product Type
1: Series number
3. Current Input Range
1: 0.200 to 2.200 A
2: 2.00 to 22.00 A
3: 20.0 to 200.0 A
4. Heater Control Type
C: ON/OFF control (SSR or contactor)
P: Phase control or cyclic control
5. Output Type
C: Relay contact output (one SPDT relay contact output)
T: Transistor output (two NPN open collector outputs)
6. Communications Specifications
FLK: RS-485
7. Power Supply Voltage
100-240VAC: 100 to 240 VAC
Classification Heater Element
Burnout
Detector
Tempera-
ture con-
troller
Power
regula-
tor (thy-
ristor)
Item K8AC-H K2CU
Heater
burnout
detection
Single-
phase heater {{ { {
Three-phase
heater {{ { {
Contactor
control
heater
{{ { {
SSR control
heater {{ { {
Phase
control
heater
×× {
Cyclic
control
heater
×× ×
Voltage fluctuation
compensation function { ××
SSR short circuit
detection function {×{×
Overcurrent detection
function {×× {
12345 6 7
K8AC-H1 @@@ -FLK 100-240VAC

K8AC-H
3
Ordering Information
■Digital Heater Element Burnout Detectors
Note: Consult with your OMRON representative if multiple heaters are connected in parallel with different heater capacities, or if a heater with
varying heater resistance is used.
■Optional Products (Sold Separately)
Current Transformers
Note: When selecting a current transformer, ensure that the rated current of the heater does not exceed the rated current of the transformer.
Heater control method Input specifications Output specifications Current input range Model
Contactor control
SSR control Two current inputs (single-/three-phase) One relay output + RS-485 0.200 to 2.200 A K8AC-H11CC-FLK
2.00 to 22.00 A K8AC-H12CC-FLK
20.0 to 200.0 A K8AC-H13CC-FLK
Two transistor outputs + RS-485 0.200 to 2.200 A K8AC-H11CT-FLK
2.00 to 22.00 A K8AC-H12CT-FLK
20.0 to 200.0 A K8AC-H13CT-FLK
Phase control (cyclic control) One relay output + RS-485 0.200 to 2.200 A K8AC-H11PC-FLK
2.00 to 22.00 A K8AC-H12PC-FLK
20.0 to 200.0 A K8AC-H13PC-FLK
Two transistor outputs + RS-485 0.200 to 2.200 A K8AC-H11PT-FLK
2.00 to 22.00 A K8AC-H12PT-FLK
20.0 to 200.0 A K8AC-H13PT-FLK
Through-hole diameter Rated current Installation method Model
5.8 mm dia. 0.200 to 22.00 A Surface-mounted with screws K8AC-CT20S
12 mm dia. Rear-surface mounted with screws
Binding band K8AC-CT20L
20.0 to 200.0 A Rear-surface mounted with screws
Binding band K8AC-CT200
30 mm dia. 20.0 to 200.0 A Surface-mounted with screws K8AC-CT200L

K8AC-H
4
Specifications
■Ratings
Note: 1. The gate input enables correct measurement by syncing to heater control. When using it with contactor ON/OFF control, receive the relay
contact output from the temperature controller or other controller with an auxiliary relay and then use this signal as the gate input signal
to the K8AC-H. The gate function can also be disabled. If it is disabled, the gate input can be used as a normal undercurrent/overcurrent
relay.
2. When using the K8AC-H for a 380 to 480-V AC power supply circuit, Use a 2:1 step-down transformer that can supply at least 10 VA to
the load.
3. Order the CTs separately.
Power supply voltage 100 to 240 VAC (50/60 Hz) (See note 2.)
Operating voltage range 85% to 110% min. of the rated power supply voltage (85 to 264 V)
Power consumption
(at max. load)
35 VA max. (at max. load)
Applicable circuits Single-phase or three-phase (with same model)
Applicable control methods Contactor ON/OFF control (e.g., temperature controller with relay output)
SSR control (e.g., temperature controller with voltage output)
Cyclic control and phase control (e.g., temperature controller with current output)
Current measurement Current measurement via two special CTs (Burnout alarm set value can be set separately for each CT.)
Measurement method Average value calculation
Gate input
signal
(See note 1.)
Contactor ON/OFF
control
Voltage = 12/24 VDC (continuous input possible to 30 VDC)
Input impedance = 4 kΩmin.
SSR control ON voltage: 9.6 VDC max., OFF voltage: 1 VDC min.
Minimum voltage pulse ON time for burnout detection: 200 ms min.
Cyclic and phase
control
4 to 20 mA DC (Burnout detection is possible for an input of 7 mA or greater.)
Input impedance = 50 Ωmax.
Output Relay contact
output:
K8AC-H@@@C-FLK
One SPDT relay contact output
Same output used for heater burnout alarms, overcurrent alarms, SSR short circuit alarms, and SSR open
circuit alarms.
0.3 A at 125 VAC (resistive load), 1 A at 30 VDC (resistive load)
Maximum switching capacity: 37.5 VA, 30 W
Mechanical durability: 50 million operations min., electrical durability: 100,000 operations min.
Transistor output:
K8AC-H@@@T-FLK
Two NPN open-collector outputs
One ALM output: Outputs heater burnout alarms and overcurrent alarms
One SSR error output: Outputs SSR short circuit and open circuit alarms.
12 to 24 VDC, 50 mA max.
OFF leakage current: 100 μA max., ON residual voltage: 1.5 V max.
Communications RS-485 1200, 2400, 4800, 9600, 19200 bps (CompoWay/F)
Indication method 7-segment digital display: No. of display digits: 4 (red)
LED status indicators: RUN (green), ADJ (orange), SET (orange), GATE (orange), SSR (orange) and ALM
(orange)
Main functions Heater burnout alarms, overcurrent alarms, SSR short circuit alarms, SSR open circuit alarms, voltage
fluctuation compensation, output ON delay timer, energy-saving mode, key protection, and power supply
voltage measurement
Ambient operating temperature −10 to +55°C (with no icing or condensation)
Ambient operating humidity 25% to 85% (with no condensation)
Storage temperature −25 to +65°C (with no icing or condensation)
Altitude 2,000 m max.
Dimensions 35 ×90 ×100 mm (W x L x H)
Case material PC (Polycarbonate)
Case color Munsell N1.5
Mounting method Mounting to a DIN Track
Special CT models (See note 3.) Current input range Applicable models
K8AC-CT20S 0.200 to 2.200 A
2.00 to 22.00 A
K8AC-H@1@@, K8AC-H@2@@
K8AC-CT20L
K8AC-CT200 20.0 to 200.0 A K8AC-H@3@@
K8AC-CT200L 20.0 to 200.0 A K8AC-H@3@@

K8AC-H
5
■Characteristics
Note: 1. Current Transformers are sold separately.
2. The values for measurement current apply to combined use with a specialized Current Transformer.
Item
Model Models for contactor control and SSR control
K8AC-H@@@C@-FLK
Models for phase control and cycle control
K8AC-H@@P@-FLK
Heater
current input
(at 10 to 30°C)
category II
Input range K8AC-H@1@@: 0.200 to 2.200 A (Current Transformer: K8AC-CT20S (5.8 dia.), K8AC-CT20L (12 dia.)
(See note 1.))
K8AC-H@2@@: 2.00 to 22.00 A (Current Transformer: K8AC-CT20S (5.8 dia.), K8AC-CT20L (12 dia.)
(See note 1.))
K8AC-H@3@@: 20.0 to 200.0 A (Current Transformer: K8AC-CT200 (12 dia.), K8AC-CT200L (30 dia.)
(See note 1.))
Measurement
accuracy
±3% rdg ±10 digits max. (See note 2.) ±6% rdg ±10 digits max. (at control level of 100%)
(See note 2.)
Vol tage
fluctuation
compensation
category II
Input range 85 to 264 VAC
Measurement
accuracy
±3% rdg ±10 digits max.
Gate input Input range 0 to12 VDC or 0 to 24 VDC
ON: 9.6 VDC max., OFF: 1 VDC min.
4 to 20 mA DC
Display cycle Selectable: Immediate, 0.2 s, 0.5 s, 1.0 s
Output ON-delay time 0.0 to 99.9 s (operating time)
Soft start time 0.0 to 99.9 s (Used when using the soft start function of a Power Controller)
Output reset method Automatic reset
Output hysteresis 1 to 999 digits
Output response time 500 ms max. 3.5 s max.
Insulation resistance 20 MΩmin. (at 500 VDC) between external terminals and case
Dielectric strength 2,000 V for 1 min between the external terminals and the case
Noise immunity Power supply terminals normal/common mode: ±1,500 V (startup 1-ns square-wave noise, pulse width:
1 μs/100 ns)
Vibration resistance Vibration: 10 to 55 Hz, Acceleration: 50 m/s2for 5 min with 10 sweeps each in X, Y, and Z directions
Shock resistance 150 m/s2 (100 m/s2for relay contacts) 3 times in 6 directions in X, Y, and Z directions
Maximum
allowable
input
Current Transformer
primary-side current
K8AC-H@1@@: 4 A: 30 s, 12 A: 1 s
K8AC-H@2@@: 40 A: 30 s, 120 A: 1 s
K8AC-H@3@@: 400 A: 30 s, 1200 A: 1 s
Gate input: 4 to 20 m 40 mA DC continuous
Voltage pulse gate
input
30 VDC continuous
Input
impedance
Gate input: 4 to 20 m 50 Ωmax.
Voltage pulse gate
input
4 kΩmax.
Weight Approx. 200 g
Memory protection Non-volatile memory (number of writes: 100,000 operations)
Installation environment Installation Category 2, Pollution Class 2
Approved standards EN 61010-1 (IEC 61010-1) (TÜV evaluation)
EMC EMI: EN61326 Industrial applications
Radiated Interference Electromagnetic Field Strength: EN55011 Group 1, class A
Noise Terminal Voltage: EN55011 Group 1, class A
EMS: EN61326 Industrial applications
ESD Immunity: EN61000-4-2: 4 kV (contact discharge)
8 kV (air discharge)
Electromagnetic Immunity: EN61000-4-3: 10 V/m 1 kHz sine wave amplitude modulation
(80 MHz to 1 GHz)
Fast Transient Burst Immunity: EN61000-4-4: 2 kV (power line)
1 kV (I/O signal line)
Surge immunity: EN61000-4-5: 1 kV (line to line, power line)
2 kV (line to ground, power line)
Conducted Noise Immunity EN61000-4-6: 3 V (0.15 to 80 MHz)
Voltage Dip/Interrupting Immunity EN61000-4-11: 0.5 cycle, 0.180°,100% (rated voltage)

K8AC-H
6
■I/O Ratings
Relay Contact Output
Transistor Output
Communications Specifications
Item Load Resistive load (cosφ= 1)
Rated load 125 VAC, 0.3 A, 30 VDC, 1 A
Maximum contact
voltage
125 VAC, 60 VDC
Maximum contact
current
1 A
Maximum switching
capacity
37.5 VA, 30 W
Minimum applicable load
(failure rate P value,
reference value)
5 VDC, 10 mV
Mechanical life
expectancy
50,000,000 operations min. (at a
switching frequency of 18,000 times/h)
Electrical life expectancy
(Ambient temperature
condition: 20°C)
100,000 operations min. (at rated load
and switching frequency of 1,800 times/
h)
Maximum load voltage 12 to 24 VDC (+10%, −15%)
Maximum load current 50 mA
OFF leakage current 100 µA max.
ON residual voltage 1.5 V max.
Item Communica-
tions
RS-485
Transmission method Two-wire, half-duplex
Synchronization method Start-stop synchronization
Baud rate 1,200, 2,400, 4,800, 9,600, or 19,200
bps
Transmission code ASCII

K8AC-H
7
Connections
■Terminal Arrangement
Note: 1. Terminals 4 to 6: Alarm output terminals. Depend on the
output type (relay output or transistor outputs).
2. Terminals 11 and 12: Gate input terminals. Depend on the
heater control type (contactor/SSR control or cyclic/phase
control).
■Current Input Circuits
CT Inputs (Heater Current)
■Output Circuits
Open Collector Outputs Contact Outputs
Note: For contact outputs, the same outputs are used for SSR error
and for heater burnouts and heater layer shorts alarm outputs.
7
CT1 CT2 Linear current
DC 4 to 20 mA RS-485
8910
7 8 910 11 12 13 14
11
Voltage pulses
0 to 12 VDC or
0 to 24 VDC
12
H8AC-H1@C@
Gate input
H8AC-H1@P@
+−
11 12
+−
13 14
CommunicationsCurrent inputs
1 2
Operating power supply
100 to 240 VAC
A(−)B(+)
COM COM
125 VAC,
AC 0.2 A
30 VDC,
DC 1 A
12 to 24 VDC,
DC 50 mA
456456
Outputs
H8AC-H1@@T H8AC-H1@@C
12 3 4 5 6
Terminals Name Description Applicable
models
1 to 2 Operating
power
supply
Connect to the operating
power supply.
All models
5 to 4,
6 to 4
Outputs Outputs SSR open or short
circuit detection results.
Outputs heater burnout or
overcurrent detection
results.
K8AC-H1@@T
(transistor
outputs)
5, 6 to 4 Outputs an OR of the status
of all alarms.
K8AC-H1@@C
(relay output)
7 to 8 Current
inputs
Connect to CT1. Current
input from CT1 secondary-
side output.
All models
9 to 10 Connect to CT2. Current
input from CT2 secondary-
side output.
11 to 12 Gate input Connect to gate signal
(voltage pulse).
K8AC-H1@C@
Connect to a 4 to 20-mA
gate signal.
K8AC-H1@P@
13 to 14 Commu-
nications
Connect to host device for
RS-485 communications.
All models
CT2
CT1
7
8
9
10
A/D
conversion
−
+A/D
conversion
−
+
4
5
6
Transistor
drive circuit
Transistor
drive circuit
COM
SSR alarm output
Heater burnout, heater layer short,
overcurrent alarm output
4
5
6
Relay
drive circuit
COM
N.C. contact
N.O. contact
+12 V

K8AC-H
8
■External Connection Example
Wiring Method When Using the K8AC-H with SSR Control Heaters
Wiring Method When Using the K8AC-H with Contactor Control Heaters
Operation Description
•If the heater current detected at either CT1 or CT2 falls
below the burnout alarm set value, an alarm is output. The
burnout alarm set value can be set separately for CT1 and
CT2.
No burnout alarm is output, however, when the
temperature controller control output is OFF.
Burnouts are detected only while the temperature
controller control output is being input to the gate input
terminals (11 and 12).
Faulty outputs do not occur because heater burnout
detection is linked with the temperature controller.
•The minimum burnout detection time is 200 ms. Shorter
burnouts are not detected.
•Turn ON the voltage fluctuation compensation function
(default = OFF) to detect power supply voltage fluctuations
and automatically adjust the burnout alarm levels to
compensate. Also, turn ON the voltage fluctuation
compensation function to detect minor current fluctuations.
Correct Usage
•Always take the control power supply from the primary
side of the SSR.
•Use temperature controllers with a 12 or 24-VDC voltage
output (30 VDC max.).
•CT1 and CT2 are special products. Use the K8AC-CT@@.
•The CTs do not have polarity.
•Connect only one CT for single-phase heaters.
Connect two CTs for three-phase heaters.
•For three-phase heaters, always set the burnout alarm set
values for both CT1 and CT2.
Operation Description
•If the heater current detected at either CT1 or CT2 falls
below the burnout alarm set value, an alarm is output. The
burnout alarm set value can be set separately for CT1 and
CT2.
No burnout alarm is output, however, when the
temperature controller control output is OFF.
Burnouts are detected only while the temperature
controller control output is being input to the gate input
terminals (11 and 12).
Faulty outputs do not occur because heater burnout
detection is linked with the temperature controller.
•The minimum burnout detection time is 200 ms. Shorter
burnouts are not detected.
•Turn ON the voltage fluctuation compensation function
(default = OFF) to detect power supply voltage fluctuations
and automatically adjust the burnout alarm levels to
compensate. Also, turn ON the voltage fluctuation
compensation function to detect minor current fluctuations.
Correct Usage
•Always take the control power supply from the primary
side of the contactor.
•Use a temperature controller with relay output.
•The input to the gate input terminals (11 and 12) must
be a DC voltage input, so wire the 24-VDC power
supply as shown in the diagram to the left.
•CT1 and CT2 are special products. Use K8AC-CT@@.
•The CTs do not have polarity.
•Connect only one CT for single-phase heaters.
Connect two CTs for three-phase heaters.
•For three-phase heaters, always set the burnout alarm set
values for both CT1 and CT2.
Heater
Power supply
SSR
CT2
CT1
Temperature
Controller
(DC voltage output)
4
3
5
6
78 910 1112
13 1412
RS-485 communications
4
5
6
For transistor output
Heater
Power supply
Contactor
CT2
CT1
Temperature
Controller
(relay output)
24-VDC
power supply
3
78 910 1112
13 1412
RS-485 communications
4
5
6
For transistor output
X
4
5
6

K8AC-H
9
Wiring Method When Using the K8AC-H with Cyclic Control Heaters
Wiring Method When Using the K8AC-H with Phase Control Heaters
Operation Description
•If the heater current detected at either CT1 or CT2
falls below the burnout alarm set value, an alarm is
output. The burnout alarm set value can be set
separately for CT1 and CT2.
No burnout alarm is output, however, when the
temperature controller control output is OFF.
Burnouts are detected only while the temperature
controller control output is being input to the gate input
terminals (11 and 12).
Burnout is detected with no errors because the
automatic adjustment of burnout alarm level is linked
to the temperature controller control output (4 to
20 mA).
•Burnout is detected when control outputs from the
temperature controller are 7 mA min.
Correct Usage
•Always take the control power supply from the primary
side of the SSR.
•Use a temperature controller with a 4 to 20-mA current
output.
•Always adjust the burnout alarm set value when the
temperature controller's control output is at 100%
(20 mA).
The value at 100% output is used as a reference for
adjusting burnout alarm levels to compensate for
inputs between 4 and 20 mA.
•CT1 and CT2 are special products. Use K8AC-CT@@.
•The CTs do not have polarity.
•Connect only one CT for single-phase heaters.
Connect two CTs for three-phase heaters.
•For three-phase heaters, always set the burnout alarm
set values for both CT1 and CT2.
Operation Description
•If the heater current detected at either CT1 or CT2
falls below the burnout alarm set value, an alarm is
output. The burnout alarm set value can be set
separately for CT1 and CT2.
No burnout alarm is output, however, when the
temperature controller control output is OFF.
Burnouts are detected only while the temperature
controller control output is being input to the gate input
terminals (11 and 12).
Burnout is detected with no errors because the
automatic adjustment of burnout alarm level is linked
to the temperature controller control output (4 to
20 mA).
•Burnout is detected when control outputs from the
temperature controller are 7 mA min.
Correct Usage
•Always take the control power supply from the primary
side of the Power Controller.
•Use a temperature controller with a 4 to 20-mA current
output.
•Always adjust the burnout alarm set value when the
temperature controller's control output is at 100% (20 mA).
The value at 100% output is used as a reference for
adjusting burnout alarm levels to compensate for inputs
between 4 and 20 mA.
•Adjust the burnout alarm set value at a 100% output for
gradient settings as well.
•If using the soft startup function with a power regulator, set
the soft startup function on the K8AC-H as well, to prevent
malfunctions.
•CT1 and CT2 are special products. Use K8AC-CT@@.
•The CTs do not have polarity.
•Connect only one CT for single-phase heaters.
Connect two CTs for three-phase heaters.
•For three-phase heaters, always set the burnout alarm set
values for both CT1 and CT2.
•When using the power regulator's gradient settings,
change the operation gate current level so that the heater
current value is within the measurement range. (The initial
value is 7 mA.)
For details on operating methods, refer to pages 18 to 19.
Heater
(See note.)
Power supply
SSR SSR
CT2
CT1
G32A-EA
Cyclic
Control Unit
Temperature
Controller
4 to 20 mA current output
3
78 910 11
12
13 1412
RS-485 communications
4
5
6
For transistor output
4
5
6
Note: Consult with your OMRON representative if multiple heaters
are connected in parallel different heater capacities, or if a
heater with varying heater resistance is used.
Heater
(See note.)
Power supply
Power
Regulator
CT2
CT1
Temperature
Controller
4 to 20 mA current output
3
78 910 1112
13 1412
RS-485 communications
4
5
6
For transistor outputs
4
5
6
Note: Consult with your OMRON representative if multiple heaters
are connected in parallel different heater capacities, or if a
heater with varying heater resistance is used.

K8AC-H
10
■Heater Connection Methods and Current
Depending on the heater connection method, the current when an error occurs will be as shown in the following table. Refer to this table when
determining burnout alarm set values.
Note: This is the current for when a 200-V, 1-kW heater is used for single-phase or three-phase operation.
Normal condition Abnormal condition
Single-phase
Three-
phase
Delta
connection
Star
connection
V
connection
200 V
5 A
5 A
1 kW
0 A
0 A
200 V
200 V
200 V
1 kW
1 kW
1 kW
8.7 A
8.7 A
8.7 A
200 V
(5 A ×3 )
7.5 A
7.5 A
)
2
3
(5 A ×3 ×
5 A
5 A
8.7 A
)
3
1
(5 A ×3 ×
200 V
200 V
1kW
1 kW
1 kW
2.9 A
2.9 A
2.9 A
200 V
)
3
1
(5 A ×
2.5 A
2.5 A
)
2
3
(5 A ×3
1×
2.5 A
2.5 A
)
2
3
(5 A ×3
1×
200 V
200 V
1 kW
1 kW
5 A
8.7 A
5 A
200 V
(5 A ×3 = 8.7 A) 1
2.5 A
2.5 A
(5 A ×)
2(5 A ×1)
5 A
5 A