omRonThree-phase Undervoltage and Phase-sequence Phase-loss RelayK8DS-PU Ideal for Monitoring 3-phase Power Supplies for Industrial Facilities and Equipment. • Greater resistance to inverter noise. new • Monitor undervoltages, phase sequence, and phase loss in three-phase three-wire circuits with one unit. • One SPDT output relay, 5 A at 250 VAC (resistive load). •World-wide power specifications supported by one unit. (Set with a rotary switch.) •Relay status can be monitored using LED indicator. A Refer to Safety Precautions on page 9. Refer to page 7 for commonly asked questions. Ordering Information List of Models Note: The input range is set with a rotary switch. * The power supply voltage is the same as the rated input voltage.

Specifications Input frequency •Relationship of Mounting Distance between K8DS-PU 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. DIN Track Distance between products: d

Connections Terminal Diagram Control Output L1 Relay output 250 VAC, 5 A (resistive load) 30 VDC, 5 A (resistive load) Input Voltages Note: Use the recommended ferrules if you use twisted wires. Power supply AC/DC Timing Charts ●Undervoltage Operation Diagram Operation Table L1 Input L2 L3 Undervoltage set value Item Flashing Alarm indicator Indicators RY_LED Undervoltage t: Operating time (0.1 to 30 s) Phase loss Undervoltage contacts t t1: Power ON lock (1 s) Phase Loss Operation Incorrect phase Phase sequence Correct phase *1 Flashing Flashing Undervoltage alarm indicator Undervoltage relay...

•Indicators Item * 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. •Setting Knobs Item 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. For 2.5 mm2 or For ferrules with smaller solid wires an insulation sleeve. Recommended ferrules Phoenix Contact • Al 1,5-8BK (for AWG16) • Al 1-8RD (for...

Setting Methods •Undervoltage Undervoltage is set using the undervoltage knob (UNDER). The undervoltage can be set to between -30% and 25% of the rated input. Turn the knob while there is an input to the input terminals until the alarm indicator flashes (when the set value and the input have reached the same level.) Use this as a guide to set the voltage. The rated input depends on the model and the rotary switch setting. Example: K8DS-PU1 with Rotary Switch Set to 200 V The rated input voltage is 200 VAC and the setting range is 140 to 250 V. •Operating Time The operating time is set using the...

Checking Operation How to Measure the Operating Time Undervoltage Change the input value quickly from 120% to 70% of the set value and measure the time required for the Relay to operate. Operating Time Adjust the slide resistor so that the voltage applied to the K8DS terminals is 80% of the set value when the auxiliary relay in connection diagram 2 operates. Close the switch and use a cycle counter to measure the operating time. Undervoltage Gradually reduce the input from 120% of the set value. The input will equal the operating value when the input goes below the set value and the alarm indicator...

Load-side Phase Loss In principle, phase loss cannot be detected on the load side because the K8DS-PU measures three-phase voltage to determine phase loss. Motor Load Phase Loss during Operation Motor load phase loss cannot be detected during operation. It can be used to detect phase loss at startup. Normally, threephase 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...

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 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...

Precautions for Safe Use 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 5. To reduce the error in the setting knob, always turn the setting knob from the minimum setting toward the maximum setting. 6. Phase loss is detected only when the power supply to the motor is turned ON. Phase loss during motor operation is not detected. 7. Phase loss can be detected...

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...