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Motor Protective Relay
K2CM
CSM_K2CM_DS_E_6_2
Solid-state Relay Enables Choice of Three
Operating Functions (Overcurrent, Openphase, and Reverse-phase)
• Protects 3-phase induction motors and their loads from damage.
• Selection and combination of operating functions from overcurrent, open-phase, and reverse-phase.
• Circuit and output relay operation can be checked by just operating the test button.
• The set time value can be checked easily because operation time
is indicated from the start of operation.
• Space-saving, integrated construction.
Note: If the K2CM is used with an inverter, the operating conditions will
depend on the load wiring length, inverter carrier frequency, basic
frequency, and load conditions. Error will occur in the operating
values of the overload elements. It is recommended to test operation
before using the K2CM.
Model Number Structure
■ Model Number Legend
K2CM-@@@-@@
1
2 3 4
5 6
5. Current setting range
LS:
2 to 8 A
L:
8 to 26 A
M:
20 to 65 A
H:
50 to 160 A
6. Operating time
None: ×1 (2 to 10 s)/ ×4 (8 to 40 s) Switchable
1. Model
K2CM: Motor relay
2. Mounting style
None: Surface-mounting, integrated type
3. Operating time characteristics
None: Inverse type
Q:
Instantaneous type
4. Supply voltage of control circuit
1:
100/110/120 VAC
2:
200/220/240 VAC
4:
400/440 VAC
7. Resetting method
None: Manual reset
A:
Automatic reset
8. Reverse-phase detection type
None: Current reverse-phase detection
V:
Voltage reverse-phase detection
Ordering Information
■ List of Models
Voltage Reverse-phase Detection Models
Time specification
Resetting
method
Manual
Current setting range
Inverse type
8 to 26 A
20 to 65 A
Instantaneous type
50 to 160 A
8 to 26 A
20 to 65 A
50 to 160 A
Operating voltage
200/220/240 VAC
Automatic 200/220/240 VAC
K2CM-2LV
K2CM-2MV
K2CM-2HV
K2CM-Q2LV
K2CM-Q2MV
K2CM-Q2HV
K2CM-2LAV
K2CM-2MAV
K2CM-2HAV
K2CM-Q2LAV
K2CM-Q2MAV
K2CM-Q2HAV
1
K2CM
Current Reverse-phase Detection Models
Time specification
Resetting
method
Manual
Inverse type
2 to 8 A
Current setting range
8 to 26 A
Instantaneous type
20 to 65 A 50 to 160 A
2 to 8 A
8 to 26 A
20 to 65 A
50 to 160 A
Operating voltage
100/110/120 VAC
K2CM-1LS
K2CM-1L
K2CM-1M
K2CM-1H
K2CM-Q1LS
K2CM-Q1L
K2CM-Q1M
200/220/240 VAC
K2CM-2LS
K2CM-2L
K2CM-2M
K2CM-2H
K2CM-Q2LS
K2CM-Q2L
K2CM-Q2M
K2CM-Q2H
400/440 VAC
---
K2CM-4L
K2CM-4M
K2CM-4H
---
K2CM-Q4L
K2CM-Q4M
K2CM-Q4H
Automatic 100/110/120 VAC
(See
200/220/240 VAC
note.)
400/440 VAC
K2CM-Q1H
K2CM-1LSA K2CM-1LA K2CM-1MA K2CM-1HA K2CM-Q1LSA K2CM-Q1LA K2CM-Q1MA K2CM-Q1HA
K2CM-2LSA K2CM-2LA K2CM-2MA K2CM-2HA K2CM-Q2LSA K2CM-Q2LA K2CM-Q2MA K2CM-Q2HA
---
K2CM-4LA K2CM-4MA K2CM-4HA ---
K2CM-Q4LA K2CM-Q4MA K2CM-Q4HA
Note: The manual resetting method must be used with reverse-phase detection.
■ Related Product
Transformer
Model
SE-PT400
Voltage specification
Secondary power
consumption
Primary side
380 to 480 V (wide power supply range) 7VA
Secondary side
190 to 240 V (wide power supply range)
Note: Use this Transformer when a voltage reverse-phase detection model is used on a 400-V line.
Specifications
■ Ratings
Other features, such as 100% overcurrent capacity and flush mounting are also available. See Model Number Legend on page 1 for details.
Supply voltage of motor circuit
200/220, 400/440 VAC, 50/60 Hz
Supply voltage of control circuit
100/110/120, 200/220/240, 400/440 VAC, 50/60 Hz
Insulation breakdown of output contact
500 VAC
Operating voltage/current of output contact NO contact: 120 VAC/2 A, 240 VAC/1 A, 440 VAC/0.5 A, 110 VDC/0.2 A, 220 VDC/0.1 A
(pf = 0.4 when breaking contact)
NC contact: 120 VAC/5 A, 240 VAC/2 A, 440 VAC/1 A, 110 VDC/0.2 A, 220 VDC/0.1 A
Contact form of output contact
Current reverse-phase detection models: SPST-NO + SPST-NC
Voltage reverse-phase detection models: SPDT
Operating current range of input circuit
2 to 160 A (Number of passes: 1)
Operating voltage range of control circuit
85% to 110% of rated voltage, but operates normally at 50% of open-phase supply voltage
Operating frequency range of control circuit 95% to 105% of rated frequency
Power consumption
Approx. 3 VA (in standby state); 5 VA (in operating state)
Overcurrent function operating value
115 ±10% of the setting value
Overcurrent function operating time setting Inverse Type
range
Inverse time both at startup and during operation:
Timer scale × 1 (s) at 600% overload
Timer scale × 3 (s) at 200% overload
Note: The above values are for a time factor setting of 1.
Instantaneous Type
Fixed time at starting (start-up lock)
• Time setting value (varies between 2 and 40 s) at 140% overload and starting
Instantaneous during operation: 0.5 s max. (when current is increased from 100 to 140% of the
set current value)
Case color
Munsell 5Y7/1
Overcurrent function operating time
characteristics
Inverse type: ±10% of maximum setting value (at 600% overload)
Instantaneous type: ±20% of maximum setting value (at 140% overcurrent and at starting)
Overcurrent function resetting value
100% min. of the setting value
Overcurrent function start-up operating
value
Inverse type: Not applicable
Instantaneous type: 30% max. of the setting value (See note.)
Open-phase operating value
85% max. of the set current value (at open-phase)
Open-phase operating time
2 s max. (at overcurrent operating value)
Reverse-phase operating value
50% max. of the current value (80% max. of the operating voltage)
Reverse-phase operating time
1 s max. (at overcurrent operating value)
Imbalance operating value
85% of the set current value
Current imbalance factor
High: 35 ±10%; Low: 60% min. (at overcurrent operating value)
where
Reverse phase portion
Imbalance factor =
× 100 (%)
Normal phase portion
Note: The start-up lock timer restarts when the operating value at starting becomes less than 30% of the set current value.
2
K2CM
■ Characteristics
Variation due to
temperature
fluctuation
Variation due to
voltage fluctuation
Variation due to
frequency
fluctuation
At 20 ±20 °C
Overcurrent:
±5% of operating value, ±10% of operating time
Open-phase:
±10% of operating value, ±10% of operating time
Reverse-phase: ±10% of operating value, ±10% of operating time
At 20 ±30 °C
Overcurrent:
±10% of operating value, ±20% of operating time
Open-phase:
±20% of operating value, ±20% of operating time
Reverse-phase: ±20% of operating value, ±20% of operating time
At 85% to 110% of Overcurrent:
±5% of operating value, ±10% of operating time
rated voltage
Open-phase:
±5% of operating value, ±10% of operating time
At 95% to 105% of Reverse-phase: ±5% of operating value, ±10% of operating time
rated frequency
Insulation resistance
10 MΩ min. (between current-carrying terminals and mounting panel)
5 MΩ min. (between current-carrying terminals and between contact poles)
Dielectric strength
2,500 VAC (between current-carrying terminals and mounting panel and between current-carrying
terminals)
1,000 VAC (between contact poles)
Permissible impulse voltage
Current reverse-phase detection models:
6,000 V (between current-carrying terminals and mounting panel)
4,500 V (between current-carrying terminals and between control power supply terminals)
Waveform: 1.2/50 μs
Voltage reverse-phase detection models:
4,500 V (between current-carrying terminals and mounting panel)
Waveform: 1.2/50 μs
Overcurrent strength of main circuit
No abnormality develops when 20 times the set current value is applied for 2 s, 2 times with a 1minute interval.
Overvoltage strength of control power
supply circuit
No abnormality develops when 1.15 times the relay’s rated voltage is applied once for 3 hours.
Variation due to waveform distortion
No malfunction occurs when pulse containing 100% of the 2nd to 9th harmonics is applied (openphase switch set to “Low”). (See note.)
Malfunction: 10 to 55 Hz, 0.3-mm double amplitude (in X, Y, and Z directions for 10 minutes each)
Destruction: 10 to 25 Hz, 2-mm double amplitude (in X, Y, and Z directions for 2 hours each)
Vibration
Shock
Test current
(reference only)
Malfunction: 98 m/s2 (approx. 10 G) in X, Y, and Z directions
Destruction: 294 m/s2 (approx. 30 G) in X, Y, and Z directions
Operating time
Set time value
Setting
characteristics of
operating time
Approx. ±30% of the maximum setting value
Service life
Electrical: 10,000 operations
Ambient temperature
Operating: −10 to 60 °C (with no icing)
Storage: −25 to 65 °C
Humidity
35% to 85%
Altitude
2,000 m max.
Note: This means that no malfunction occurs with the open-phase element, but the operating value of the overload element may vary.
3
K2CM
Connections
■ Voltage Reverse-phase Detection Models
Manual Operation Low-voltage Circuit (Highcapacity Motor)
Terminal Arrangement
200 VAC
50/60Hz
R
Ta
Tc Tb U
V
S
T
W
Stop
Start
Output contacts Control power
(SPDT)
supply
• Perform the external connections by referring to the examples given below.
• Obtain the control power supply from the same phase as the power supply to
the magnet contactor coil.
• Connect the phase advancing capacitors closer to the power supply than the
current transformer, as shown in the examples.
• Tighten the terminal screws to a torque of 0.98 N·m max. (The appropriate
tightening torque is 0.49 to 0.67 N·m.)
• Use of insulated solderless terminals is recommended for connection to the
Relay terminals (M3.5).
Note: 1. In principle, the K2CM must be surface mounted with the terminal
block facing downward.
2. Use M5 screws with spring washers and flat washers for mounting.
Tighten the screws to a torque of 1.77 N·m max. (The appropriate
tightening torque is 1.08 to 1.57 N·m.)
Magnet
contactor
Phase advancing
capacitor
Current converter for
measuring device @/5A
Alarm
buzzer
R
U
A
1
M
Motor
S
V
B
2
BZ
T
W
C
3
Ta Tc Tb
U
V
W
Motor protective relay
Automatic Operation Low-voltage Circuit
Manual Operation Low-voltage Circuit
200 VAC
50/60Hz
R S T
200 VAC
50/60Hz
R S T
Stop
Automatic
contact
Start
Magnet
contactor
Magnet
contactor
BZ
Phase advancing
capacitor
Alarm
buzzer
BZ
Phase
advancing
capacitor
Alarm
buzzer
R
U
A
1
S
V
B
2
T
W
C
3
R
U
A
1
Ta Tc Tb
U
V
S
V
B
2
T
W
C
3
Ta Tc Tb
W
U
V
W
Motor protective relay
M
Motor protective relay
Motor
M
Motor
Manual Operation High-voltage Circuit
Manual Operating Low-voltage Circuit (
Start)
3, 300 VAC
50/60Hz
R S T
Transformer @/200V
200 VAC
50/60Hz
R S T
High-tension
fuse
Stop
X/a
Stop
Start
High-voltage
magnet contactor
Start
Auxiliary
relay
Magnet
contactor
Phase
advancing
capacitor
X
Phase advancing
capacitor
Alarm
buzzer
R
U
A
1
S
V
B
2
T
W
C
3
Current converter for
measuring device @/5A
Alarm
buzzer
Ta Tc Tb
U
V
W
Motor protective relay
changeover
M
BZ
BZ
M
High-voltage
motor
R
U
A
1
S
V
B
2
T
W
C
3
Ta Tc Tb
U
V
W
Motor protective relay
Note: Connect the phase advancing capacitor on the power supply
side of the Motor Protective Relay as shown in the above diagrams.
4
K2CM
■ Current Reverse-phase Detection Models
Terminal Arrangement
Manual Operation Low-voltage Circuit (Highcapacity Motor)
200 VAC
50/60Hz
R S T
a1 c1
b2 C2
S1 S2
Stop
Start
Output contacts Control power
(NO and NC)
supply
• Perform the external connections by referring to the examples given below.
• Connect the phase advancing capacitors closer to the power supply than the
current transformer as shown in the examples.
• Tighten the terminal screws to a torque of 0.98 N·m max. (The appropriate
tightening torque is 0.49 to 0.67 N·m.)
• Use of insulated solderless terminals is recommended for connection to the
Relay terminals (M3.5).
Note: 1. In principle, the K2CM must be surface mounted with the terminal
block facing downward.
2. Use M5 screws with spring washers and flat washers for mounting.
Tighten the screws to a torque of 1.77 N·m max. (The appropriate
tightening torque is 1.08 to 1.57 N·m.)
Manual Operation Low-voltage Circuit
Magnet
contactor
Phase advancing
capacitor
Current converter for
measuring device @/5A
Alarm
buzzer
S
S
V
B
2
T
W
C
3
a1 c1 b2 c2 s1 s2
Motor
Motor protective relay
Automatic Operation Low-voltage Circuit
200 VAC
50/60Hz
R
R
U
A
1
M
BZ
200 VAC
50/60Hz
R S T
T
Stop
Start
Automatic
contact
Magnet
contactor
Magnet
contactor
BZ
Phase
advancing
capacitor
R
U
A
1
S
V
B
2
T
W
C
3
BZ
Phase advancing
capacitor
Alarm
buzzer
R
U
A
1
a1 c1 b2 c2 s1 s2
Alarm
buzzer
S
V
B
2
T
W
C
3
a1 c1 b2 c2 s1 s2
Motor protective relay
Motor protective relay
M
M
Motor
Motor
Manual Operating Low-voltage Circuit (
Start)
Manual Operation High-voltage Circuit
3,300 VAC
50/60Hz
R S T
200 VAC
50/60Hz
R S T
Transformer @/100V
High-tension
fuse
Stop
X/a
Stop
Start
Start
High-voltage
magnet contactor
Magnet
contactor
Auxiliary
relay
Phase
advancing
capacitor
Alarm
buzzer
R
U
A
1
S
V
B
2
T
W
C
3
BZ
X
Phase advancing
capacitor
a1 c1 b2 c2 s1 s2
Current converter for
measuring device @/5A
BZ
Alarm
buzzer
Motor protective relay
changeover
M
M
High-voltage
motor
R
U
A
1
S
V
B
2
T
W
C
3
a1 c1 b2 c2 s1 s2
Motor protective relay
Note: Connect the phase advancing capacitor on the power supply
side of the Motor Protective Relay as shown in the above
diagrams.
5
K2CM
Output Circuits
■ Internal Circuit and Operation Description
Reset circuit
C2
To each
circuit
X/b2
b2
Voltage Reverse-phase
Detection Models
With the voltage reverse-phase
detection models, the circuit
section enclosed by A in the
diagram on the left is configured as
shown below. The circuit section
enclosed by C is not used.
C1
U
V
LED
LED
Reset circuit
To each circuit
X
3
Start time
setting circuit
Start-up
detecting circuit
Relay drive
circuit
To each circuit
Instantaneous Type
With instantaneous-type
models, the circuit section
enclosed by B is
configured as shown below.
Overcurrent
detecting circuit
Open-phase
detecting circuit
LED
C
OR circuit
M
Overcurrent
indicator
Open-phase
indicator
Reversephase
indicator
Reverse-phase
level detecting
circuit
Reverse-phase
detecting circuit
Rectifier/smoothing circuit
Rectifier/smoothing circuit
Open-phase level
detecting circuit
2
Note: Applies to current reversephase detection models
only.
To OR circuit
Rectifier/smoothing circuit
W
AND circuit
Maximum value
detecting circuit
a1
X/a1
Reverse-phase
detecting circuit
1
Time-setting
circuit
Voltage
circuit
for test
Rectifier/smoothing circuit
S2
B
Test button
Overcurrent
detecting circuit
A
Current-setting
circuit
S1
To each circuit
R S T
As shown on the right, the K2CM
detects abnormalities in motor M
by checking its line current. The
motor’s current signal is detected
by the current transformer and is
processed separately for each
phase and input to the respective circuits. In each circuit, parallel judgement of failure such as
overcurrent, open-phase, or
reverse-phase (see note) is
made based on the input signals.
If a failure is detected in a circuit,
the circuit’s output is input to the
indication circuit to illuminate the
corresponding LED indicator and
also input to the relay drive circuit to drive relay X, resulting in a
trip signal to be externally output
from it. The three major circuits
are described below.
Reset button
Rectifier/smoothing circuit
Inverse and Instantaneous
Types
1) Overcurrent Circuit
Overcurrent Detecting Circuit
Starting Time Setting Circuit (Instantaneous Type)
This circuit detects when the current reaches the overcurrent operating level (115% of the set current value).
This circuit performs time setting using the VR for setting the start-up
lock time and obtains fixed time-limit characteristics using an RC
time-limiting circuit.
Time Setting Circuit (Inverse Type)
This circuit performs time setting using the VR (variable resistor) for
the operating time setting and obtains inverse-type characteristics
using an RC time-limiting circuit. The operating time can be set within
a range from 2 to 10 s or 8 to 40 s by operating the setting switch
using a VR. The VR covers a time range 5 times the standard range.
Start-up Detecting Circuit (Instantaneous Type)
Instantaneous-type models output a trip signal instantaneously when
the motor current exceeds the overcurrent operating value (115% of
the set current value). At the start of motor operation, a starting current several times the rated current flows and so to prevent the motor
circuit being tripped by the starting current, instantaneous operation
is not enabled until a fixed time tc has elapsed, as shown in the figure. Instantaneous operation starts after tc has elapsed. Motor starting time “to” varies, depending on motor type, within a range from
several seconds to several tens of seconds. There are even slight differences in starting time between the same type of motors and so be
sure to set tc so that to to<tc is satisfied. If to>tc, the motor circuit will
be tripped after tc has elapsed. The fixed time limit tc at the start of
motor operation is called “lock time”. The start-up detecting circuit
detects the starting operation level (30% max. of the set current
time).
Operation at start-up is shown in the figure below. After the motor
turns ON at point A, the motor’s starting current exceeds the start-up
operating value and so the RC time-limiting circuit starts charging. If,
for example, the motor current descends below the start-up operating value (30% max. of the set current value) at point B before the
start-up lock time, tc, has elapsed, the RC time-limiting circuit is reset
immediately and when the motor current rises above the start-up
operating value again at point C, the RC time-limiting circuit starts
charging again. After the start-up lock time has elapsed (at point D),
instantaneous operation is enabled. At the start of operation, the
motor current is at its peak immediately after operation starts. It then
lowers and settles at the rated current. The peak current is about 5 to
6 times the rated current and takes from several seconds to several
tens of seconds to settle to the rated current. This time varies largely
depending on type of motor and the nature of motor load (wt). Therefore, it is necessary to obtain the motor’s starting time for operation
with the load and to set a start-up lock time that allows for a margin of
error. Do not set an unnecessarily long start-up lock time. If the startup lock time is too long and an accident due to overcurrent occurs at
the start of operation, the trip signal will not be output until the startup lock time has elapsed, possibly resulting in motor burnout.
Overcurrent
operating value
Start-up
operating value
Overcurrent operating value
Motor current
to
Start
to: Motor's starting time
tc: Lock time at start of operation
tc
Instantaneous operation enabled
Operating mode
Motor
current
A
B
C
tc
Operation
mode
Start
D
E
F
tc
G
*
**
*
Start
H
tc
*
**
Start
Output
*: Fixed time-limit operation
tc: Start-up lock time
**: Instantaneous operation enabled
Trip
Fixed time-limit
operation
6
K2CM
2) Open-phase Circuit
T phase
1.0
Open-phase Level Detecting Circuit
"Low"
Open-phase
Maximum phase of
switch
current: R phase = 1.0
"High"
This circuit detects when the current reaches the open-phase operating level (85% max. of the set current value). Therefore, open-phase
is not detected until the maximum phase of the current exceeds 85%
of the set current value.
The following imbalance factors can be selected by setting the openphase switch.
“High” . . .Operating imbalance factor: 35 ±10%
“Low” . . .Operating imbalance factor: 60% min.
The imbalance factor can be easily obtained from the following
graph. In the graph, the horizontal axis indicates the maximum phase
of the current whereas the two vertical axes indicate the remaining
two phases. The maximum phase of the current is taken to be 1.0 as
a reference point. The imbalance factor is obtained as a percentage
from the curve around the center of the graph. Obtain the imbalance
factor for a motor current with IR = 100 A, IS = 70 A, and IT = 60 A as
follows:
1. On the R axis, locate point A, where IR = 1.0.
"Low"
operating
area
Non-operating
area
A
25%
Open-phase Detecting Circuit
Output of the maximum value detecting circuit is divided and used as
reference values for comparison with the output of the rectifier/
smoothing circuits for the respective phases. If a phase has a value
lower than the reference value, the K2CM judges it to be open-phase
and outputs an open-phase signal.
"High"
operating
area
35%
0.5
60%
0
0.5
1.0
S phase
3) Reverse-phase Circuit
1. Current Reverse-phase Detection Models
Reverse-phase Level Detecting Circuit
This circuit detects whether the current is in the operating level (50%
max. of the set current value) as a precondition to detect the reversephase.
2. Move from point A to point B, where IS = 0.7 on the S axis.
Reverse-phase Detecting Circuit
3. On the T axis, locate point C, where IT = 0.6.
The current reverse-phase detecting method is employed for detecting reverse-phase as shown below. After the motor starts operating,
the current phase becomes transiently unstable during T1 (approx.
0.4 s) and so reverse-phase detection is not performed during this
period but it is performed during T2 (approx. 0.1 s). After T2 has
elapsed, reverse-phase detection is not performed. For this reason,
this method cannot be applied to cases where instantaneous
reverse-phase is not permitted. When a reverse-phase is detected,
the relay is held in the latched state even after the motor current
stops (in both manual and automatic release types).
4. Follow the curves that pass through points B and C and locate the
intersection point D.
5. Locating the point corresponding to point D on the imbalance factor curve gives an imbalance factor of 36%. Take the maximum
phase of current on the horizontal axis without considering axes
R, S, and T.
1.6
1.6
1.5
1.5
1.4
1.4
1.3
1.3
1.2
1.2
1.1
1.1
1.0
1.0
0.9
0.9
Start
Motor
T1
T2
Non-detecting area
Detecting area
0.7 Point B
10.0
15.0
Point C 0.6
0.6
20.0
25.0
0.5
0.5
30.0
35.0
Point D 40.0
45.0
50.0
55.0
60.0
65.0
70.0
75.0
0.4
0.3
0.2
0.1
0.2
0.3
0.4
0.5 0.6
R (S, T)
Reverse-phase Detecting Circuit
Reverse-phase detecting is performed by using the voltage reversephase detection method.
0.4
0.3
0.2
U
V
0.1
80.0
85.0
90.0
95.0
0.1
2. Voltage Reverse-phase Detection Models
0.7
0.8
0.9
W
Reverse-phase level
detecting circuit
0.7
0.0
0.0
0.8 S (T, R)
5.0
OR phase circuit
T (R, S) 0.8
Reverse-phase output
0.0
1.0
Point A
Generally, in open-phase detection, detecting a complete openphase is sufficient. In such a case, set the open-phase switch to the
“Low” position. If using the motor in an imbalanced condition causes
problems, or when detecting internal open-phases of a delta-connected motor, set the switch to the “High” position. Depending on the
motor’s load condition and the imbalance of the power supply, however, special consideration may be required for the detection of internal open-phases in delta-connected motors. Consult your OMRON
representative before using this method. When a transformer is connected as a load, the harmonics increase at low loads. Therefore, in
such a case, set the open-phase switch to the “Low” position.
By voltage division within the above RC phase circuit, the output
becomes 0 V in the normal state or 1.5 Vuv in the reverse-phase
state. Using the output from this circuit, the reverse-phase level
detecting circuit detects when the current reaches the reverse-phase
operating level (80% or less of the control power supply).
7
K2CM
Nomenclature
Trip Indicator
In normal operation, only the upper half of the display window is colored orange,
whereas when the motor circuit has tripped, the entire display window becomes orange.
10 (side) 9
8 7 6
Current-setting Knob
• By operating the setting knob, set the current value to
be equal to the rated current of the motor to be used.
The current-setting knob uses the same scale as the
rated current. Therefore, the operating value will be
115% of the set current value.
Example: Operating current value
= 12 × 1.15 (115%) = 13.8 A
• The List of Current Settings shows an example. The
rated current differs depending on the motor’s type,
construction, manufacturer, etc. Therefore, set the
operating current after checking the specifications of
the motor.
Time-setting knob*
Test Button
Reset Button
Inverse Type
• With manual resetting models, when the motor circuit trips during
normal operation or test operation, the operation indicators and
the output relay can be immediately reset by pressing the reset
button.
• When the motor circuit trips due to reverse-phase with automatic
resetting models, the operation indicators and the output relay can
be immediately reset by pressing the reset button.
• Reset button operation is ineffective when the operation power
supply is OFF. When the motor circuit trips during normal operation, identify the abnormal input function by checking the LED indicators, then turn OFF the power switch of the main circuit and
proceed with troubleshooting. After the abnormality is removed,
turn ON the power switch of the main circuit to reset the K2CM.
• Operation checks of the overcurrent function can be performed.
• Pressing the test button for the time-setting value will cause the motor
circuit to trip.
• With manual resetting models, even if the test button is released after
the motor circuit has tripped, the circuit remains tripped, whereas with
automatic resetting models, the motor circuit continues operating and
the output relay releases.
• Be sure to perform the test operation with the overcurrent switch set to
ON. Set both the open-phase and reverse-phase switches to OFF. If
one of these switches is set to ON, the motor circuit may trip if an
open-phase or reverse-phase occurs before an overcurrent does.
Instantaneous Type
• Perform the test operation with input current at 0 and the overcurrent
switch set to ON.
• Pressing the test button for the set start-up lock time will cause the
motor circuit to trip.
• With manual resetting models, even if the test button is released after
the motor circuit has tripped, the circuit remains tripped, whereas with
automatic resetting models, the motor circuit continues operating and
the output relay releases.
Time-setting Knob
• Set the required operating time by operating the time-setting knob.
(With instantaneous-type models, the set operating time is used as the
start-up lock time).
Note: 1. The setting scale is the operating time when 600% of
the current value is input.
2. The required operating
time varies depending on
the type of motor, load condition, etc. You can take the
time from when the motor
starts to when the motor
enters the steady state as
a guide for setting this value. When setting the operating time for submersible
motors, which require very
short operating times, consult the manufacturer to
obtain the correct operating time. An operating time
shorter than 5 s can be
used as a rough guide.
• The scale multiplying factor
can be selected by the time
scale multiplying factor
switch.
Scale
Time scale
multiplying multiplying factor
factor
switch
Time scale
value
× 1 (s)
× 4 (s)
2
2
8
3
3
12
4
4
16
5
5
20
6
6
24
7
7
28
8
8
32
9
9
36
10
10
40
Deciding the Number of Primary Conductor Passes
• When using a motor with a small current rating, decide the number of primary conductor passes through the current transformer
holes and the tap setting by referring to the List of Current Settings.
• Pass all the three wires through the respective holes of the current
transformer. Basically, the wires should be passed through the
specified holes. If this is difficult, however, they can be passed
through any holes provided that the phase order is R, S, and T.
1 pass
R S
T
2 passes
R S
T
• If the wires are passed through the holes only once, a current within
the full scale of the current-setting knob can be set. If they are
passed more than once, however, the current setting range will
change according to the number of passes. The current setting
range when the number of conductor passes is n can be obtained
by dividing the full scale of the current-setting knob by n. For example, the current setting range of the K2CM-@@L@ is 8 to 26 A when
the wires are passed only once. This range is 4 to 13 A when the
wires are passed twice, 2 to 6.5 A when the wires are passed four
times, and 1 to 3.25 A when the wires are passed eight times.
The wires can be passed through the holes any number of times. It
is convenient for the calculation, however, if the number of passes
is 2, 4, or 8.
• The signal from a high-voltage motor is input to the Motor Protective Relay via an external current transformer. In this case, the current can be set in the same manner as above by dividing the rated
current of the high-voltage motor by the transformation ratio of the
current transformer.
8
K2CM
LED Indicators
3. Reverse-phase Setting Switches
When the motor circuit trips due to overcurrent, open-phase, or
reverse-phase, the respective LED indicator lights (continuously).
The overcurrent indicator also indicates the start of operation.
These switches select the reverse-phase detection function and
reverse-phase polarity. By selecting the reverse-phase polarity
accordingly, the K2CM can operate normally without changing the
connections when wired with the order of the phases reversed.
Overcurrent operating value
(115% of current-setting value)
Motor current
Bright
Bright
Dimmed
Start
Reverse-phase
detecting
function
ON
Enabled
OFF
Disabled
Reverse-phase
polarity
Normal
The motor circuit trips at reversephase when a reverse-phase is
detected.
Reverse
Used when a reverse-phase
connection is made in the power line
of the motor at a point before the
current transformer (including
external current transformer).
Trip
• With the inverse-type models, when the motor current exceeds the
overcurrent operating value, the overcurrent indicator blinks at the
bright level and then remains lit at the dimmed level. After the operating time has elapsed, with the manual resetting models, the
motor circuit trips and the overcurrent indicator remains lit at the
bright level, whereas with automatic resetting models, the indicator
remains lit at the bright level until the motor current descends below
the resetting value.
• Since the indicator status is not stored in memory when the operation power supply is turned OFF, be sure to check which indicators
were illuminated when the motor circuit was tripped.
If the K2CM detects reverse-phase although the motor is rotating in
the forward direction (e.g., because of incorrect wiring of power
lines), set the reverse-phase polarity switch to the “Reverse” position
to enable normal operation.
Phase condition
Connections
The functions of the K2CM can be used in the following seven combinations. For each function, turn ON the corresponding setting
switch.
Function
Overcurrent
Open-phase
1
ON
2
ON
3
4
ON
ON
ON
5
ON
6
ON
7
ON
ON
S
T
Reverse
R
S
T
Reverse
R
S
T
R
S
T
(A)
R
S
T
R
S
Motor
relay
Reverse-phase
Combination
Normal
R
T
(C)
Motor
relay
(B)
Motor
relay
(D)
M
M
M
Reverse-phase
polarity switch
position
Normal
Normal
Normal
Trip
None
Yes
None
Direction of
motor rotation
Forward
Reverse
(See below.)
Reverse
ON
ON
ON
When the setting switches for overcurrent, open-phase, or reversephase function are turned OFF, the following functions becomes
invalid.
Function setting switch
set to OFF
Invalid function
Overcurrent
Time setting and multiplication
Open-phase
“High” and “Low” imbalance factors
Reverse-phase
“Forward” and “Reverse” function
1. Overcurrent Setting Switches
These switches select the overcurrent setting and the multiplying
factor linked with operating time setting.
Overcurrent
ON
detecting function OFF
Countermeasure
Enabled
Disabled
Time setting
× 4 (s) Time setting scale value × 4 = 8 to 40 s
multiplying factor × 1 (s) Time setting scale value × 1 = 2 to 10 s
2. Open-phase Setting Switches
These switches select the open-phase detecting function and the
“High” or “Low” current imbalance factor for operation.
Open-phase
detecting
function
ON
Enabled
OFF
Disabled
Imbalance factor
High
The motor circuit operates at an
operating imbalance factor of 35
±10%.
Low
The motor circuit operates at an
operating imbalance factor of 60%.
Reversephase
polarity
switch
position
Reverse Reverse Reverse Reverse
Wiring
Wiring
changed
at (A).
Direction of
motor rotation
Wiring
changed
at (B).
Wiring
changed
at (C).
Wiring
changed
at (D).
Forward
Note: The K2CM detects reverse-phase at a point before the current
transformer. If a reverse connection is made at the load side far
from the current transformer and the motor rotates in the reverse direction, the K2CM does not detect the reverse-phase.
Reverse-detectable Range
R
S
T
R
S
T
Detectable:
M
Reverse-phase state can be detected with the
motor protective relay only on the power supply
side.
Undetectable: Reverse-phase state on the motor side cannot
be detected with the motor protective relay.
* The OR phase circuit in the above figure combines a resistor and
capacitor. The reverse phase detection circuit detects when the
reversed signals detected by the OR phase circuit reach the operating level (i.e., 80% or less of the control power supply voltage).
9
K2CM
Engineering Data
Operating time (s)
Time scale multiplying factor
(× 4) (× 1)
280 70
240 60
200 50
160 40
Time scale
10
0.2
This graph shows the
behavior when the
current changes from
100% of the currentsetting value to the
percentage shown on
the horizontal axis.
8
6
120 30
Overload Operating Time
Characteristics for Instantaneous Type
Operating time (s)
Overload Operating Time
Characteristics for Inverse Type
0.1
4
2
80 20
40 10
0
Operating time (s)
Typical Characteristics of
Open-phase Operation
2.0
0
100
200
300
400
500
600
700
Motor current (percentage of current-setting value)
This graph shows the behavior when
the current changes from 100% of the
current-setting value to the percentage
shown on the horizontal axis.
1.0
100
200
300
400
500
600
700
Motor current (percentage of current-setting value)
Typical Characteristics of
Reverse-phase Operation
Operating time (s)
0
0.6
This graph shows the behavior when
the current changes from 100% of the
current-setting value to the percentage
shown on the horizontal axis.
0.5
0.4
0.3
0.2
0.1
0
100
200
300
400
500
600
700
Motor current (percentage of current-setting value)
0
100
200
300
400
500
600
700
Motor current (percentage of current-setting value)
10
K2CM
Dimensions
Note: All units are in millimeters unless otherwise indicated.
Surface-mounting Models
126
80
6
60
52 46.5
11.5
15
55
33
11
48.5
4
Six, M3 terminal screws
Four, 6-dia. mounting holes or
four, M5 mounting-screw holes
120
52±0.5
36
33.5
Three, 20-dia. holes
80±0.5
33.5
Operating Procedures
■ Operation, Setting, and Indication
Based on the current value of the motor to be used, perform the setting of each item of the K2CM Motor Protective Relay.
List of Current Settings (when using a 200-VAC motor)
Setting
Type*
K2CM-@@LS@
Number of passes
1
Time scale value
2 to 8
Current setting range (A)
2 to 8
K2CM-@@L@
1
2
4
K2CM-@@M@
8
8 to 26
8 to 26
4 to 13 2 to 6.5 1 to 3.25
K2CM-@@H@
1
1
20 to 65
50 to 160
20 to 65
50 to 160
Motor*** Rated output (kW) Rated current (A)**
0.2
1.8
0.4
2.8
0.75
4.2
1.5
7.3
2.2
10
3.7
16.1
5.5
24
7.5
32
11
45
15
61
18.5
74
22
87
30
117
37
143.0
*
The squares (@) represent the symbols defined under Model Number Legend.
** The rated current is the current at full load.
*** Supply: Low-voltage 3-phase basket type inductive motor, full-load characteristics of 200 VAC, 4-pole, totally-enclosed.
Note: When using a large-capacity or high-voltage motor whose capacity is 45 kW or more, calculate the rated current/alternating current ratio by
converting with the alternating current ratio of the external current transformer.
11
K2CM
Testing Method
■ Current Reverse-phase Detection Models
200 V
50/60 Hz
(3-phase)
U
V
W
The operating characteristics listed in the table below are tested using the circuit shown on the right. Decide the number of conductor
100 VAC
passes through the holes of the current transformer in accordance with the operating current range of the Motor Protective
50/60HzRelay and by
SW1
referring to the current setting method described under Operation, Setting, and Indication.
3φSD
Y
CC
100 V
C
±
a1 c1 b2 c2 s1 s2
SW2
Minimum set time is 2 s.
K2CM Motor Protective Relay
R1
R1
R2
Test item
Inverse type
Three-phase voltage regulator (5 to 15 A)
AC ammeter (5 A)
AC voltmeter (300 V)
Cycle counter
Auxiliary relay (15 A)
R1:
R 2:
SW1:
SW2:
Variable resistor (50 Ω, 400 W + 400 W)
Fixed resistor (50 Ω, 400 W + 400 W)
Knife switch (3-phase)
Toggle switch
Test procedure
Operating value
Overcurrent
3φSD:
A:
V:
CC:
Y:
Operating time
1. Turn ON SW1 and SW2. Increase the current to 600% of
1. Turn ON SW1.
the set current value by adjusting the voltage regulator.
2. Turn ON SW2 to operate auxiliary relay Y.
Turn OFF SW1 and SW2.**
3. Gradually increase the current by adjusting the voltage
regulator. With inverse-type models, read the value of the 2. Turn ON SW1.
current when the overcurrent LED indicator blinks. With 3. Turn ON SW2 and read the position (i.e., time) of the
instantaneous-type models, read the value when it lights
pointer of cycle counter CC when CC is stopped by the
(continuously).*
operation of the K2CM. The read time is the operating time
for inverse-type models and the lock time of the instanta4. Turn OFF SW1 and SW2.
neous-type models.
4. Turn OFF SW1 and SW2.
Instantaneous
type
1. Turn ON SW1 and SW2. Increase the current to 100% of
the set current value by adjusting the voltage regulator.
Turn OFF SW1 and SW2.
2. Turn ON SW1 and SW2 again and wait 2 seconds minimum.
3. Using the voltage regulator, abruptly increase the current
to 140% of the set current value. Confirm that the K2CM
performs instantaneous operation.
4. Turn OFF SW1 and SW2.
Open-phase
1. Open (disconnect) any one of the input phases for the current transformer.
2. Turn ON SW1 and SW2. Gradually increase the current by
adjusting the voltage regulator.
3. Confirm that the K2CM operates at a current no greater
than 85% of the set current value and that, at this current,
the trip indicator is orange and the open-phase LED indicator lights.
4. Turn OFF SW1 and SW2.
1. Open (disconnect) any one of the input phases for the current transformer.
2. Turn ON SW1 and SW2. Increase the currents of the other
two phases to 115% of the set current value by adjusting
the voltage regulator. Turn OFF SW1 and SW2 temporarily.
3. Turn ON SW1 and SW2 again. Read the position (i.e.,
time) of the pointer of cycle counter CC when CC is
stopped by the operation of the K2CM.
4. Turn OFF SW1 and SW2.
Reverse-phase
1. Interchange any two phases at a position closer to the
power supply than the current transformer. (In the above
figure, phases U and V are interchanged as shown by the
dotted lines.)
2. Turn ON SW1 and SW2. Decrease the current to 50% of
the set current value by adjusting the voltage regulator.
Then turn OFF SW1 and SW2 temporarily.
3. Turn ON SW1 and SW2 again. Confirm that the K2CM
operates, the trip indicator is orange, and that the reversephase LED lights.
4. Turn OFF SW1 and SW2.
1. Interchange any two phases at a position closer to the
power supply than the current transformer. (In the above
figure, phases U and V are exchanged as shown by the
dotted lines.)
2. Turn ON SW1 and SW2. Increase the current to 100% of
the set current value by adjusting the voltage regulator.
Then turn OFF SW1 and SW2 temporarily.
3. Turn ON SW1 and SW2 again. Read the position (i.e.,
time) of the pointer of cycle counter CC when CC is
stopped by the operation of the K2CM.
4. Turn OFF SW1 and SW2.
* Balance the currents between phases by adjusting variable resistor R1.
** If a current equal to 600% of the set current value cannot be attained by adjusting the voltage regulator, increase the number of conductor passes
through the holes of the current transformer.
12
K2CM
■ Voltage Reverse-phase Detection Models
The operating characteristics listed in the table below are tested
using the circuit shown on the right. Decide the number of conductor
passes through the holes of the current transformer in accordance
with the operating current range of the Motor Protective Relay and by
referring to the current setting method described under Operation,
Setting, and Indication.
200 V
50/60 Hz
(3-phase)
U
V
W
SW1
100 VAC
50/60 Hz
3φSD
Y
CC
100 V
C
±
Ta Tc Tb U
SW2
V W
Minimum set time is 2 s.
K2CM Motor Protective Relay
R1
R1
R2
Test item
Inverse type
Three-phase voltage regulator (5 to 15 A)
AC ammeter (5 A)
AC voltmeter (300 V)
Cycle counter
Auxiliary relay (15 A)
R1:
R 2:
SW1:
SW2:
Variable resistor (50 Ω, 400 W + 400 W)
Fixed resistor (50 Ω, 400 W + 400 W)
Knife switch (3-phase)
Toggle switch
Test procedure
Operating value
Overcurrent
3φSD:
A:
V:
CC:
Y:
Operating time
1. Turn ON SW1 and SW2. Increase the current by adjusting
1. Turn ON SW1.
the voltage regulator to 600% of the set current value.
2. Turn ON SW2 to operate auxiliary relay Y.
Turn OFF SW1 and SW2.**
3. Gradually increase the current by adjusting the voltage
regulator. With inverse-type models, read the value of the 2. Turn ON SW1.
current when the overcurrent LED indicator blinks. With 3. Turn ON SW2 and read the position (i.e., time) of the
instantaneous-type models, read the value when it lights
pointer of cycle counter CC when CC is stopped by the
(continuously).*
operation of the K2CM. The read time is the operating time
for inverse-type models and the lock time of the instanta4. Turn OFF SW1 and SW2.
neous-type models.
4. Turn OFF the SW1 and SW2.
Instantaneous
type
1. Turn ON SW1 and SW2. Increase the current to 100% of
the set current value by adjusting the voltage regulator.
Then turn OFF SW1 and SW2.
2. Turn ON SW1 and SW2 again and wait 2 seconds minimum.
3. Using the voltage regulator, abruptly increase the current
to 140% of the set current value. Confirm that the K2CM
performs the instantaneous operation.
4. Turn OFF SW1 and SW2.
Open-phase
1. Open (disconnect) any one of the input phases for the current transformer.
2. Turn ON SW1 and SW2. Gradually increase the current by
adjusting the voltage regulator.
3. Confirm that the K2CM operates at a current no greater
than 85% of the set current value and that, at this current,
the trip indicator is orange and the open-phase LED indicator lights.
4. Turn OFF SW1 and SW2.
1. Open (disconnect) any one of the input phases for the current transformer.
2. Turn ON SW1 and SW2. Increase the currents of the other
two phases to 115% of the set current value by adjusting
the voltage regulator. Turn OFF SW1 and SW2 temporarily.
3. Turn ON SW1 and SW2 again. Read the position (i.e.,
time) of the pointer of cycle counter CC when CC is
stopped by the operation of the K2CM.
4. Turn OFF SW1 and SW2.
Reverse-phase
1. Change the phase sequence to reverse-phase by switch- 1. Put the voltage input in the reverse-phase state.
ing the U and W input terminals of the K2CM as shown by 2. Turn ON SW1 and SW2 and read the position of the
the dotted lines.
pointer of cycle counter CC when CC is stopped.
2. Turn ON SW1 and SW2 and confirm that the K2CM oper- 3. Turn OFF SW2.
ates.
3. Add a three-phase voltage regulator to the U, V, and W terminal inputs.
4. Adjust the voltage regulator and confirm that the K2CM
operates at less than 80% of the rated supply voltage.
* Balance the currents between phases by adjusting variable resistor R1.
** If a current equal to 600% of the set current value cannot be attained by adjusting the voltage regulator, increase the number of conductor passes
through the holes of the current transformer.
13
K2CM
Safety Precautions
■ Correct Use
• A power supply with a frequency other than commercial frequency
cannot be used as the control power supply.
• Use of circuits containing a high percentage of harmonics, such as
circuits incorporating SCR control circuits, VVVF inverters, or rectifiers, may cause errors and malfunctions. Consult your OMRON
representative for details.
• When applying the K2CM to the protection of a high-voltage motor
or low-voltage, high-capacity motor, use an external rectifier that
does not saturate at currents up to 600% of the rated motor current
and thus permits a large overcurrent; otherwise, the K2CM will output a tripping signal because of imbalanced operation when an
overcurrent occurs and, with reverse-type models, the motor may
be damaged by burning.
• Never tamper with the trip indicator. Use the reset switch to reset
the K2CM.
• When a power failure occurs in the control power supply, the K2CM
is not reset even when the reset switch is pressed. This is not an
error. The K2CM can be reset only when control power is applied to
it.
• Be sure to remount the front cover after detaching it for operating or
setting the switches on the front panel.
• The rectifier and control circuits are combined by tightening the two
screws on the right and left sides. Never loosen these screws.
• The variable resistors used to make settings are equipped with
mechanisms to stop them rotating outside the valid scale range. Do
not rotate the variable resistors at a torque of 1 kg·cm or more.
• When using the K2CM-@@@A (instantaneous, automatic resetting), be sure to apply power to the Motor Protective Relay from the
same power line as the magnet contactor for switching the motor.
• Be sure to provide the control power supply for the K2CM-@@@@V
(voltage reverse-phase detection) from the same line as the motor.
• If current reverse-phase detection models are used in a circuit with
distorted current waveforms, the reverse-phase element may perform an unwanted operation. In such circuits, use of the K2CM@@@@V (voltage reverse-phase detection) is recommended
because it is not affected at all by current waveform distortion.
• The operation check using the test button is intended to check the
operation of the overcurrent functions. Therefore, be sure to turn
ON the overcurrent switch. Also, at this time, turn OFF the openphase switch and reverse-phase switch to prevent unnecessary
operations from being performed.
• The operating time of inverse-type models and the lock time of the
instantaneous-type models depend upon the set operating time.
Therefore, do not hold down the test button for more than the set
operating time.
• The reverse-phase can be detected in the wiring up to the current
transformer (including an external current transformer). Check the
wiring between the current transformer and the motor before starting the motor.
• Current reverse-phase detection models cannot be used in applications that do not allow even momentary reversals of motor direction.
• Jogging of the motor can be performed. For details, consult your
OMRON representative.
• When using the K2CM to control inching shorter than 0.5 s, the
reverse-phase level detection circuit may operate. In this case, be
sure to use the K2CM with the reverse-phase switch set to OFF.
• The K2CM is basically intended to protect three-phase loads. Its
overcurrent function, however, can also be applied to single-phase
loads. In this case, the conductors can be passed through the holes
in any direction and sequence.
• When applying the K2CM to a circuit with a high imbalance factor
due to the nature of the power supply or load, actually measure the
imbalance factor and select the open-phase sensitivity accordingly
(i.e., set the open-phase switch to either the high or low position).
The K2CM cannot be used if the imbalance factor is 60% or higher.
• When applying the K2CM to the protection of three-phase transformers, give consideration to the imbalance factor due to singlephase loads.
Combination
Function setting switches
Overcurrent
1
2
Openphase
ON
5
ON
6
ON
7
ON
OFF
ON
ON
ON
ON
ON
ON
OFF
ON
OFF
NOTE
Reversephase
ON
ON
ON
Openphase
ON
ON
3
4
LED indicators
Reverse- Overcurphase
rent
OFF
ON
OFF
ON
ON
If the inputs for combinations of two or more functions are
simultaneously generated, the K2CM detects the inputs in
the order reverse-phase, open-phase, overcurrent. Take
combination 4 as an example. If the open-phase and overcurrent occur at the same time, there is insufficient time to
detect the overcurrent because the open-phase is first detected and the K2CM outputs the tripping signal (causing
the magnet contactor to turn off). Therefore, the overcurrent indicator does not light.
14
K2CM
■ Maintenance and Inspection
The K2CM Motor Protective Relay offers very stable characteristics.
To maintain these characteristics for a long time, the following
inspections are recommended.
Q&A
Q
What is the VA consumption of the CT section?
Daily Inspection
The consumption is 0.4 VA/phase max. for any CT section.
The purpose of daily inspection is to discover causes of failure before
using the Motor Protective Relay. This inspection depends somewhat
on the perception of the operator as it includes visual checking, etc.
Classification
Inspection items
Connections
Loosening, damage, and dust collection at
screw terminals, damage to wiring insulation
sheaths, excessive force applied on wirings,
adhesion of foreign objects to terminal
screws
Q
As shown in the following figure, insert the K2CM and turn
OFF the reverse-phase switch before using the K2CM.
Motor Protective Relay Adhesion of foreign objects and dust to the
operation panel, shift of set value, indication
status of operation indicators and trip indicator, presence/absence of front cover, loosening of screws combining rectifier and
control circuits, deformation of case, abnormal temperature on housing surface
External rectifier
What action is required if an inverter circuit is used?
Inverter
Motor
• Always insert the K2CM on the secondary side (load side)
of the inverter.
Loosing of terminals, unusual odor, discoloration of surface
Mounting
location
This inspection is performed by turning OFF the power at regular
intervals to check the aging caused by long-time operation. It is recommended that periodic inspection is performed once a year.
Inspection item
Overcurrent
NG
Conditionally OK
Open-phase
NG
Conditionally OK
Reverse-phase
NG
NG
• The current waveform on the inverter power supply side is
distorted, so the K2CM may malfunction.
Adhesion of dust and foreign objects to
terminals, cracks in insulators around
terminal block, burn damage to wirings,
damage to setting knobs, selector
switches, test button, and reset button,
damage to insulators of solderless terminals, rust and discoloration of screw
terminals
Operating characteristics
Inverter load
• Error may occur in the operating values depending on the
inverter specifications and settings. Set the values after
performing tests and confirming operation.
Motor Protective Relay
Classification
Inverter power
supply
Element
Periodic Inspection
Construction
M
K2CM
• The inverter load side contains a large high-frequency
component, so the K2CM may malfunction due to phase
reversal.
• Depending on the specifications and settings of the
inverter, overloads and open phases may also cause the
K2CM to malfunction.
Refer to Testing Method.
Insulation resistance
Between terminals and mounting panel
Operation check with test
button
Checking of operating time, operation
indicators, and trip indicator
Q
What action is required if single phase is used?
External Rectifier
The following describes the operating procedure for using a
single phase with the K2CM.
Check for adhesion of dust and foreign objects, damage to wirings by
burning, and loosening of mounting screws.
• Connection Method
Pass wires through any two of the three holes on the
K2CM.
K2CM
M
Motor
• If a single phase is used, set the open-phase and reversephase switch to OFF. Make the overload settings so that
they match the motor current.
• Do not apply control power supply voltage between the VW terminals if a model with voltage reverse-phase
detection is used.
ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.
To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.
In the interest of product improvement, specifications are subject to change without notice.
15
Terms and Conditions Agreement
Read and understand this catalog.
Please read and understand this catalog before purchasing the products. Please consult your OMRON representative if you
have any questions or comments.
Warranties.
(a) Exclusive Warranty. Omron’s exclusive warranty is that the Products will be free from defects in materials and workmanship
for a period of twelve months from the date of sale by Omron (or such other period expressed in writing by Omron). Omron
disclaims all other warranties, express or implied.
(b) Limitations. OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, ABOUT
NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OF THE PRODUCTS. BUYER
ACKNOWLEDGES THAT IT ALONE HAS DETERMINED THAT THE
PRODUCTS WILL SUITABLY MEET THE REQUIREMENTS OF THEIR INTENDED USE.
Omron further disclaims all warranties and responsibility of any type for claims or expenses based on infringement by the
Products or otherwise of any intellectual property right. (c) Buyer Remedy. Omron’s sole obligation hereunder shall be, at
Omron’s election, to (i) replace (in the form originally shipped with Buyer responsible for labor charges for removal or
replacement thereof) the non-complying Product, (ii) repair the non-complying Product, or (iii) repay or credit Buyer an amount
equal to the purchase price of the non-complying Product; provided that in no event shall Omron be responsible for warranty,
repair, indemnity or any other claims or expenses regarding the Products unless Omron’s analysis confirms that the Products
were properly handled, stored, installed and maintained and not subject to contamination, abuse, misuse or inappropriate
modification. Return of any Products by Buyer must be approved in writing by Omron before shipment. Omron Companies shall
not be liable for the suitability or unsuitability or the results from the use of Products in combination with any electrical or
electronic components, circuits, system assemblies or any other materials or substances or environments. Any advice,
recommendations or information given orally or in writing, are not to be construed as an amendment or addition to the above
warranty.
See http://www.omron.com/global/ or contact your Omron representative for published information.
Limitation on Liability; Etc.
OMRON COMPANIES SHALL NOT BE LIABLE FOR SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
LOSS OF PROFITS OR PRODUCTION OR COMMERCIAL LOSS IN ANY WAY CONNECTED WITH THE PRODUCTS,
WHETHER SUCH CLAIM IS BASED IN CONTRACT, WARRANTY, NEGLIGENCE OR STRICT LIABILITY.
Further, in no event shall liability of Omron Companies exceed the individual price of the Product on which liability is asserted.
Suitability of Use.
Omron Companies shall not be responsible for conformity with any standards, codes or regulations which apply to the
combination of the Product in the Buyer’s application or use of the Product. At Buyer’s request, Omron will provide applicable
third party certification documents identifying ratings and limitations of use which apply to the Product. This information by itself
is not sufficient for a complete determination of the suitability of the Product in combination with the end product, machine,
system, or other application or use. Buyer shall be solely responsible for determining appropriateness of the particular Product
with respect to Buyer’s application, product or system. Buyer shall take application responsibility in all cases.
NEVER USE THE PRODUCT FOR AN APPLICATION INVOLVING SERIOUS RISK TO LIFE OR PROPERTY OR IN LARGE
QUANTITIES WITHOUT ENSURING THAT THE SYSTEM AS A WHOLE HAS BEEN DESIGNED TO ADDRESS THE RISKS,
AND THAT THE OMRON PRODUCT(S) IS PROPERLY RATED AND INSTALLED FOR THE INTENDED USE WITHIN THE
OVERALL EQUIPMENT OR SYSTEM.
Programmable Products.
Omron Companies shall not be responsible for the user’s programming of a programmable Product, or any consequence
thereof.
Performance Data.
Data presented in Omron Company websites, catalogs and other materials is provided as a guide for the user in determining
suitability and does not constitute a warranty. It may represent the result of Omron’s test conditions, and the user must correlate
it to actual application requirements. Actual performance is subject to the Omron’s Warranty and Limitations of Liability.
Change in Specifications.
Product specifications and accessories may be changed at any time based on improvements and other reasons. It is our
practice to change part numbers when published ratings or features are changed, or when significant construction changes are
made. However, some specifications of the Product may be changed without any notice. When in doubt, special part numbers
may be assigned to fix or establish key specifications for your application. Please consult with your Omron’s representative at
any time to confirm actual specifications of purchased Product.
Errors and Omissions.
Information presented by Omron Companies has been checked and is believed to be accurate; however, no responsibility is
assumed for clerical, typographical or proofreading errors or omissions.
2016.4
In the interest of product improvement, specifications are subject to change without notice.
OMRON Corporation
Industrial Automation Company
http://www.ia.omron.com/
(c)Copyright OMRON Corporation 2016 All Right Reserved.