OMRON K8DS-PM2 Relay

オムロン K8DS series slim three-phase voltage + phase-reversal & phase-loss monitoring relays deliver integrated protection for industrial 3-wire three-phase power systems. A single unit monitors four major faults simultaneously: 過電圧, 不足電圧, phase loss and phase reversal. Featuring enhanced anti-interference performance against inverters, it supports adjustable wide industrial voltage ranges from 380V to 480V. Adopting a slim 17.5mm standard DIN rail housing, it drastically cuts cabinet installation space. Widely installed on the power supply side of power equipment including three-phase asynchronous motors, ウォーターポンプ, air compressors and conveyor lines, it prevents equipment damage and production downtime caused by grid abnormalities.

Step-by-Step Model Code Breakdown

フルモデル: `K8DS-PM2`

1. K8DS: Series code for OMRON slim monitoring relays, corresponding to the 17.5mm DIN rail mounting form factor
2. 午後: Function type code, representing combined functions of three-phase voltage monitoring, phase reversal detection and phase loss detection
3. 2: Voltage grade code, matching 3-wire three-phase AC380/400/415/480V input specifications (サフィックス “1” stands for AC200~240V grade)

主要な技術仕様

Cross Reference of Same Series Models

1. Same Function, Different Voltage Grades

2. Full K8DS Series Function Comparison

典型的なアプリケーションシナリオ

1. Front-end Protection for Three-Phase Asynchronous Motors: Connected in series to the control circuit of the main circuit contactor for real-time power supply status monitoring. It instantly cuts off the control circuit upon phase loss or phase reversal to avoid motor burnout, ideal for long-running power equipment such as fans, ウォーターポンプとエアコンプレッサー.
2. Incoming Power Monitoring for Control Cabinets: Mounted at the incoming side of power distribution cabinets to monitor voltage quality of the entire cabinet’s three-phase supply. It outputs alarm signals for overvoltage or undervoltage faults to trigger sound-light alarms or upper monitoring systems.
3. Front-End Power Protection for Inverters: Designed with enhanced anti-inverter interference capability, it is installed on the input side of inverters to detect grid voltage abnormalities and protect inverter rectifier modules against surges and phase loss damage.
4. Conveying Systems for Automated Production Lines: Matched with conveyor and roller motor groups to uniformly monitor three-phase phase sequence and voltage, preventing production accidents caused by reversed equipment operation due to wrong phase sequence wiring.
5. Protection for Central Air Conditioning & 冷凍ユニット: Installed in the power supply circuit of compressors for commercial buildings and industrial refrigeration to monitor three-phase power conditions and ensure safe operation of refrigeration compressors.

Common Troubleshooting Matrix

Typical Application Scenarios of OMRON K8DS-PM2

As a slim four-in-one three-phase monitoring relay integrating overvoltage, 不足電圧, phase loss and phase reversal protection, the K8DS-PM2 is positioned as an economical power protection device for industrial three-phase power loads. Its applications fall into three core categories: three-phase load protection, power quality monitoring, and anti-interference drive matching, 詳細は次のとおりです:

1. Front-End Protection for General Three-Phase Power Loads (Most Widely Used)

This is the dominant basic application of the model, providing power-side fault protection for all types of three-phase inductive loads and serving as a direct replacement for traditional single-function phase sequence relays.

1. Body Protection for Three-Phase Asynchronous Motors

取付位置: Connected in series to the coil control circuit of the motor main circuit contactor, or wired to PLC emergency stop interlock input terminals

Core Problems Solved: Overheating and burnout of motor windings from phase-loss operation; mechanical accidents from reversed equipment rotation due to wrong phase sequence; accelerated insulation aging and shortened service life under sustained over/undervoltage

Typical Compatible Equipment: General power equipment including fans, ウォーターポンプ, エアコンプレッサー, 破砕機, machine tool spindles and lifting motors

アプリケーションの価値: Fast 0.1s-level response for phase loss and phase reversal, directly cutting the control circuit upon faults. Single-unit protection cost is far lower than motor repair and production downtime losses.

2. Specialized Protection for Industrial Pumps

取付位置: Incoming side of electrical control boxes for centrifugal pumps, submersible pumps, screw pumps and other pump equipment

Core Problems Solved: Pump overload burnout caused by phase loss; damaged mechanical seals and bearings plus out-of-control pipeline pressure from impeller reverse rotation due to reversed phase sequence

Typical Applicable Scenarios: Cooling circulation water pumps, 化学プロセスポンプ, hydraulic station oil pumps, water supply and drainage pump sets

アプリケーションの価値: Adjustable 0.1~30s delay avoids false shutdowns from short-term grid voltage sags while guaranteeing reliable actuation under severe faults.

1. Supporting Protection for Inverter & Drive Systems (Differentiated Advantage Scenarios)

Equipped with enhanced harmonic and electromagnetic interference resistance, the K8DS-PM2 can be directly installed inside inverter cabinets, making it highly suitable for inverter drive applications.

1. Power Protection on Inverter Input Side

取付位置: Main circuit incoming terminals of inverters, DIN rail mounted inside inverter cabinets

Core Problems Solved: Damage to inverter rectifier modules and DC bus capacitors from grid phase loss or sharp voltage surges/drops; false alarms and misoperation of ordinary phase sequence relays under harmonic interference

Typical Applicable Scenarios: Variable-speed fan & pump systems, production line inverter drive systems, air compressor inverter retrofitting projects

アプリケーションの価値: Tolerates high-order harmonics generated by inverters for stable operation without misactuation, while safeguarding core power components of inverters.

2. Power Monitoring for Soft Starters & Servo Drive Systems

取付位置: Incoming side of soft starters, main power inlet of multi-axis servo control cabinets

Core Problems Solved: Drive failures from instantaneous voltage dips during equipment startup; thyristor burnout of soft starters caused by phase loss

アプリケーションの価値: Wide voltage tolerance accommodates voltage fluctuations during startup, with a built-in 1s power-up blocking function to prevent false protection triggering at power-on.

Ⅲ. Industry-Specific Engineering Application Scenarios

1. 冶金 & Mining Industry

Power cabinets for belt conveyors and scraper conveyors: Mass monitoring of power supply status for multiple drum motors to prevent full production line shutdown from single motor burnout due to phase loss

Control circuits for ball mills and vibrating feeders: Withstands grid surges and voltage fluctuations generated by startup/shutdown of large plant equipment

Hoist and winch drive systems for mining: Phase reversal protection eliminates risks of reversed lifting direction, complying with mine safety regulations.

2. 化学薬品 & 製薬産業

Agitator motors and metering pump sets for reaction kettles: Ensures stable power supply for continuous production processes, triggering process interlock shutdown upon faults to avoid material scrapping and safety incidents

Purified water & water-for-injection circulation systems: Stable power supply guarantees compliant water quality for pharmaceutical processes and prevents scrapped production batches due to power anomalies

Cabinets for hazardous explosion-proof areas: Compliant with industrial EMC standards, compatible with explosion-proof control cabinets to monitor three-phase power integrity.

3. Municipal & 水処理産業

Water plant delivery pump houses and booster pump stations: Uniformly fitted to multiple pump units to guarantee uninterrupted urban water supply and fast switchover to standby pumps during faults

Aeration fans and sludge dewaterers in sewage treatment plants: Adapts to voltage drops and mild three-phase unbalance from long-distance power supply within plants

Municipal flood drainage pump stations: Prevents pump equipment failure from phase loss or overvoltage under heavy-load operation in rainy seasons to secure drainage capacity.

4. 工事 & Building Industry

Chilled water units and cooling tower fans of central air conditioning: Protects main compressor motors and avoids damaged valve plates from reversed compressor rotation caused by wrong phase sequence

Fire water pumps and smoke exhaust fans: Meets fire code requirements for terminal power monitoring and ensures reliable operation of fire-fighting loads

Power circuits for elevators and escalators: Monitors supply phase sequence and voltage quality to eliminate safety hazards from power system faults.

5. ロジスティクス & 自動生産ライン

Roller conveyor and sorting machine motor groups: Unified power monitoring for full production lines to prevent material collision accidents from reversed conveying direction due to on-site wiring phase sequence errors

Stacker and shuttle car systems for automated warehouses: Guarantees reliable power supply to avoid damage to precision logistics equipment from power anomalies

OEM packaging & filling production lines: Slim 17.5mm design fits compact small control cabinets and significantly saves internal cabinet space.

1. Supporting Equipment for Complete Machinery & Export Projects
2. Incoming Power Monitoring for MCC / PLC Cabinets

Installed at the power inlet of motor control centers and automated control cabinets to monitor three-phase power status for the entire cabinet. Relay output contacts can be linked with sound-light alarms or upper SCADA systems. Four LED indicators enable on-site rapid identification of fault types (過電圧 / 不足電圧 / 位相損失 / 位相反転).

2. Standard Matching for Export Equipment

Supports four selectable voltage grades (380V/400V/415V/480V) to fit grid standards across China, 欧州連合, 東南アジア, the Middle East and other regions. Fully certified with CE, UL and CSA international approvals to meet export machinery compliance requirements, covering global projects with a single model.

3. Terminal Protection for Diesel Generator Sets

Mounted on the load output side of diesel generators to monitor output voltage stability and phase sequence, preventing damage to downstream precision loads caused by abnormal generator voltage regulation or reversed phase sequence wiring.