New Product
1
Phase-sequence Phase-loss Relay
K8DS-PH
Three-phase Phase-sequence Phase-loss
Relay Using Voltage Detection Method
• Lineup includes a 17.5-mm slim, compact model.
• Greater resistance to inverter noise.
• Distinguishes between correct phases, phase sequence, and phase
loss when power is turned ON.
• Supports phase loss detection when the motor is operating.
• Output status can be monitored using LED indicator.
•Ideal to prevent reverse operation of motors.
Ordering Information
List of Models
* The power supply voltage is the same as the rated input voltage.
Refer to Safety Precautions on page 8.
Refer to page 7 for commonly asked questions.
For the most recent information on models that have been
certified for safety standards, refer to your OMRON website.
Function Rated input voltage* Relay output Model
Phase sequence and phase
loss monitoring
3-phase, 3-wire 200 to 480
VAC SPDT × 1 K8DS-PH1
K8DS-PH
2
Ratings and Specifications
Ratings
Rated input voltage 3-phase, 200 to 480 VAC (3-wire)
Input load Approx. 2.7 VA
Operating time Phase sequence 0.1 s±0.05 s
Phase loss 0.1 s max. (when the voltage changes rapidly from 100% to 0% of rated voltage)
Reset method Automatic reset
Indicators Power (PWR): Green, Relay output (RY): Yellow
Output relays One SPDT relay (NC operation)
Output relay ratings
Rated load
Resistive load
5 A at 250 VAC
5 A at 30 VDC
Maximum switching capacity: 1,250 VA, 150 W
Minimum load: 5 VDC, 10 mA (reference values)
Mechanical life: 10 million operations min.
Electrical life: 5 A at 250 VAC or 30 VDC:50,000 operations
3 A at 250 VAC/30 VDC:100,000 operations
Ambient operating temperature −20 to 60°C (with no condensation or icing)
Storage temperature −25 to 65°C (with no condensation or icing)
Ambient operating humidity 25% to 85% (with no condensation)
Storage humidity 25% to 85% (with no condensation)
Altitude 2,000 m max.
Terminal screw tightening torque 0.49 to 0.59 N·m
Terminal wiring method
Recommended wire
Solid wire: 2.5 mm2
Twisted wires: AWG16, AWG18
Note: 1. Ferrules with insulating sleeves must be used with twisted wires.
2. Two wires can be twisted together.
Recommended ferrules
Al 1,5-8BK (for AWG16) manufactured by Phoenix Contact
Al 1-8RD (for AWG18) manufactured by Phoenix Contact
Al 0,75-8GY (for AWG18) manufactured by Phoenix Contact
Case color N1.5
Case material PC and ABS, UL 94 V-0
Weight Approx. 60 g
Mounting Mounts to DIN Track.
Dimensions 17.5 × 80 × 74 mm (W×D×H)
K8DS-PH
3
Specifications
Input voltage range 200 to 480 VAC
Input frequency 50/60 Hz (no presumed range)
Overload capacity Continuous 500 V
Phase loss detection level
80%±10% of rated input
Calculation Formula
= 1 − ((Highest phase-to-phase voltage − Lowest phase-to-phase voltage)/Average three-
phase phase-to-phase voltage)
Applicable
standards
Conforming standards EN 60947-5-1
Installation environment (pollution level 2, installation category III)
EMC EN 60947-5-1
Safety standards UL 508 (Recognition), Korean Radio Waves Act (Act 10564),
CSA: C22.2 No.14, CCC: GB14048.5
Insulation resistance
20 MΩ min.
Between external terminals and case
Between input terminals and output terminals
Dielectric strength
2,000 VAC for one minute
Between external terminals and case
Between input terminals and output terminals
Noise immunity 1,500 V power supply terminal common/normal mode
Square-wave noise of ±1 µs/100 ns pulse width with 1-ns rise time
Vibration resistance Frequency: 10 to 55 Hz, acceleration 50 m/s2
10 sweeps of 5 min each in X,Y, and Z directions
Shock resistance 100 m/s2, 3 times each in 6 directions along 3 axes
Degree of protection Terminals: IP20
Distance between products d [mm]
Ambient temperature [°C]
0
10
20
30
40
50
60
70
5 101520253035 5040 45
K8DS
No.3
K8DS
No.2
K8DS
No.1
K8DS
No.4
K8DS
No.5
DIN Track Distance between products: d
Sample: K8DS-PH
Distance between products: 0, 5, and 10 mm min.
Test method
●Relationship of Mounting Distance between K8DS-PH Relays
and Ambient Temperature (Reference Values)
The following diagram shows the relationship between the mounting distances and the
ambient temperature.
If the relay is used with an ambient temperature that exceeds these values, the
temperature of the K8DS may rise and shorten the life of the internal components.
K8DS-PH
4
Connections
Terminal Diagram
Note: Use the recommended ferrules if you use twisted wires.
Wiring Example
Timing Charts
●Phase Sequence and Phase Loss Operation
Diagram
Note: 1. The K8DS-PH1 output contacts are normally operative.
2. The Relay will not operate if the input voltage drops below
70% of the minimum input value because L2 and L3 are
also used to provide power.
3. Phase loss cannot be detected on the load side because
this detection is based on the voltage.
L1 L2 L3
11
12
Control Output
Relay output
250 VAC, 5 A (resistive load)
3-phase,
3-wire
power
supply
30 VDC, 5 A (resistive load)
14
Relay Output
Input Voltages
Phase-to-phase voltage:
200 to 480 VAC
L1
L2 L3
14 12 11
14 12 11
L1 L2 L3
L1
L2
L3
3-phase
voltage Motor
Power supply
AC/DC
L1
L2
L3
L1
L3
L2
L3
L2
L1
L1
L2
L3
L2
L1
L3
Relay 11-14
Phase Loss Operation Phase Sequence Operation
Input
K8DS-PH
5
Nomenclature
Front
●Indicators
* This indicator uses the input across L2 and L3 as the internal power
supply. It will not light unless there is an input across L2 and L3.
Note: 1. Use either a solid wire of 2.5 mm2 maximum or a ferrule with
insulating sleeve for the terminal connection.
The length of the exposed current-carrying part inserted into
the terminal must be 8 mm or less to maintain dielectric
strength after connection.
Recommended ferrules
Phoenix Contact
•Al 1,5-8BK (for AWG16)
•Al 1-8RD (for AWG18)
•Al 0,75-8GY (for AWG18)
2. Tightening torque: 0.49 to 0.59 N·m
Operation Methods
Connections
●Input
Connect using L1, L2, and L3.
Make sure the phase sequence is wired correctly. The Unit will not
operate normally if the phase sequence is incorrect.
●Outputs
Terminals 11, 12, and 14 are the output terminals SPDT.
* Use the recommended ferrules if you use twisted wires.
Power indicator
Relay status indicator
Terminal block
(See notes 1 and 2.)
L1 L2 L3
14 12 11
Item Meaning
Power indicator
(PWR: Green) Lit when power is being supplied*.
Relay status indi-
cator
(RY: Yellow)
Lit when relay is operating (normally lit).
For 2.5 mm2 or
smaller solid wires
For ferrules with
an insulation sleeve.
8 mm max. 8 mm max.
Load
Voltage input
Signal output
14
12
L1
L2
L3
11
Relay signal
output
L1 L2 L3
K8DS-PH
6
Dimensions (Unit: mm)
Phase-sequence Phase-loss Relay
Optional Parts for DIN Track Mounting
17.5 74
80
69
44
45
K8DS-PH1
*Dimensions in parentheses are for the PFP-50N.
4.5
15 25 25
10 10
1,000 (500)*
25 25
15 (5)*
35±0.3
7.3±0.15
27±0.15
1
●DIN Tracks
PFP-100N
PFP-50N
K8DS-PH
7
Checking Operation
Phase Sequence
Switch the wiring, as shown by the dotted lines in the
connection diagram, to reverse the phase sequence and
check that the K8DS operates.
Phase Loss
Create a phase loss for any input phase and check that the
K8DS operates.
Connection Diagram
Can phase loss be detected on the load side?
In principle, phase loss cannot be detected on the load side
because the K8DS-PH measures three-phase voltage to
determine phase loss.
Is it possible to detect phase losses for motor loads while
the motor is operating?
Phase loss can be detected while the motor is operating.
However, the detection conditions depend on the load
conditions that are shown in the following figure. Understand
these characteristics when using this feature.
Normally, three-phase motors will continue to rotate even if
one phase is open. The three-phase voltage will be induced
at the motor terminals. The diagram shows voltage induction
at the motor terminals when phase R has been lost with a
load applied to a three-phase motor. The horizontal axis
shows the motor load as a percentage of the rated load, and
the vertical axis shows voltage as a percentage of the rated
voltage. The solid line in the this graph shows the voltage that
is induced at the motor terminals when a phase loss occurs
while the motor is operating under various loads. The figure
below shows how a phase loss that occurs while the motor is
operating causes an imbalance in the voltage across each
motor terminal. The K8DS-PH1 detects phase loss when the
motor is operating when the voltage is unbalanced.
(Detection occurs when the imbalance is 80% of the
maximum phase). The K8DS-PH1 cannot detect phase loss
with light motor loads because the voltage imbalance is too
small. The detectable range is shown by the diagonal lines.
Characteristic Curve Diagram
Note: For phase loss of phase R. VST, VTR, and VRS indicate the motor
terminal voltage at phase loss.
Questions and Answers
Q
L1 L1
L2 L2
L3 L3
3φ,
200 VAC
Q
Q
100
95
90
85
80
75
70
65
60
55
50
45
10 0 20 30 40 50 60 70 80 90
100 110
VST
VTR
VRS
Note: This characteristic curve shows the approximate
values only.
Voltage (as a percentage of rated voltage)
Motor load (as a percentage of rated load)
Detectable
area
K8DS-PH
8
Safety Precautions
Be sure to read the precautions for all models in the website at the following URL: http://www.ia.omron.com/.
Warning Indications
Meaning of Product Safety Symbols
Electrical shock may occasionally cause serious injury.
Confirm that the input voltage is OFF before starting any
wiring work and wire all connections correctly.
Electrical shock may cause minor injury.
Do not touch terminals while electricity is being supplied.
There is a risk of minor electrical shock, fire, or device failure.
Do not allow any pieces of metal, conductors, or cutting chips
that occur during the installation process to enter the product.
Explosions may cause minor injuries. Do not use the product
in locations with inflammable or explosive gases.
There is a risk of minor electrical shock, fire, or device failure.
Do not disassemble, modify, repair, or touch the inside of the
product.
Loose screws may cause fires. Tighten terminal screws to the
specified torque of 0.49 to 0.59 N·m.
Use of excessive torque may damage the terminal screws.
Tighten terminal screws to the specified torque of 0.49 to
0.59 N·m.
Use of the product beyond its life may result in contact welding
or burning. Make sure to consider the actual operating
conditions and use the product within its rated load and
electrical life count. The life of the output relay varies
significantly with the switching capacity and switching
conditions.
WARNING
Indicates a potentially hazardous situation
which, if not avoided, will result in minor or
moderate injury, or may result in serious
injury or death. Additionally there may be
significant property damage.
CAUTION Indicates a potentially hazardous situation
which, if not avoided, may result in minor or
moderate injury or in property damage.
Precautions for Safe
Use
Supplementary comments on what to do or
avoid doing, to use the product safely.
Precautions for
Correct Use
Supplementary comments on what to do or
avoid doing, to prevent failure to operate,
malfunction, or undesirable effects on
product performance.
Used to warn of the risk of electric shock under
specific conditions.
Used for general prohibitions for which there is no
specific symbol.
Used to indicate prohibition when there is a risk of
minor injury from electrical shock or other source if
the product is disassembled.
Used for general mandatory action precautions for
which there is no specified symbol.
WARNING
CAUTION
K8DS-PH
9
1. Do not use or store the product in the following locations.
•Locations subject to water or oil
•Outdoor locations or under direct sunlight
•Locations subject to dust or corrosive gases (particularly
sulfurizing gases, ammonia, etc.)
•Locations subject to rapid temperature changes
•Locations prone to icing and dew condensation
•Locations subject to excessive vibration or shock
•Locations subject to wind and rain
•Locations subject to static electricity and noise
•Habitats of insects or small animals
2. Use and store the product in a location where the ambient
temperature and humidity are within the specified ranges. If
applicable, provide forced cooling.
3. Mount the product in the correct direction.
4. Do not wire the input and output terminals incorrectly.
5. Make sure the input voltage and loads are within the
specifications and ratings for the product.
6. Make sure the crimp terminals for wiring are of the specified size.
7. Do not connect anything to terminals that are not being used.
8. Use a power supply that will reach the rated voltage within 1
second after the power is turned ON.
9. Keep wiring separate from high voltages and power lines that
draw large currents.
Do not place product wiring in parallel with or in the same path as
high-voltage or high-current lines.
10.Do not install the product near equipment that generates high
frequencies or surges.
11.The product may cause incoming radio wave interference. Do not
use the product near radio wave receivers.
12.Install an external switch or circuit breaker and label it clearly so
that the operator can quickly turn OFF the power supply.
13.Make sure the indicators operate correctly. Depending on the
application environment, the indicators may deteriorate
prematurely and become difficult to see.
14.Do not use the product if it is accidentally dropped. The internal
components may be damaged.
15.Be sure you understand the contents of this catalog and handle
the product according to the instructions provided.
16.Do not install the product in any way that would place a load on it.
17.When discarding the product, properly dispose of it as industrial
waste.
18.The product must be handled only by trained electrician.
19.Prior to operation, check the wiring before you supply power to
the product.
20.Do not install the product immediately next to heat sources.
21.Perform periodic maintenance.
Observe the following operating
methods to prevent failure and
malfunction.
1. Use the input power and other power supplies and converters
with suitable capacities and rated outputs.
2. The distortion in the input waveform must be 30% max. If the
input waveform is distorted beyond this level, it may cause
unnecessary operation.
3. The product cannot be used for thyristor control or on the
secondary side of an inverter. To use the product on the
secondary side of an inverter, install a noise filter on the primary
side of the inverter.
4. Phase loss can be detected only from the input contacts to the
power supply side. Phase loss cannot be detected from the input
contacts to the load side.
5. When cleaning the product, do not use thinners or solvents. Use
commercial alcohol.
Mounting and Removing
•The product may be mounted in any direction, but it must be
mounted securely and as level as possible.
•To mount the product to the DIN Track, hook it on the DIN Track at
(A) and then press in on the Unit in direction (B).
•To remove the product, insert a flat-blade screwdriver at (C) and
pull down the hook to release the Unit.
•Leave at least 30 mm of space between the product and other
devices to allow easy installation and removal.
Precautions for Safe Use Precautions for Correct Use
(A)
(B)
30 mm min.
(C)
Hook
MEMO
10
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.
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Programmable Products.
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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
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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
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confirm actual specifications of purchased Product.
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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.
0513
Authorized Distributor:
In the interest of product improvement,
specifications are subject to change without notice.
Cat. No. N190-E1-01 0314 (0314)
© OMRON Corporation 2014 All Rights Reserved.
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