WEG DWE-3 Electronic Motor Protection Relay

The WEG DWE-3 is an electronic motor protection relay designed for comprehensive protection of large three-phase induction motors from 11 kW to 630 kW and above in critical Saudi industrial applications. Unlike thermal-magnetic MPCBs which provide only overload and short-circuit protection, the DWE-3 delivers a full suite of motor protection functions through microprocessor-based algorithms, enabling precise, programmable protection that adapts to motor thermal history, starting conditions, and ambient temperature — essential for the critical large motors used in Saudi Aramco oil and gas processing facilities, SABIC petrochemical plants, desalination stations, and power generation facilities.

Protection Functions

The DWE-3 provides the following protection functions: phase overload (Class 5, 10, 20, 30 selectable), phase unbalance detection (trip threshold adjustable), single-phase loss detection with fast trip, undercurrent/no-load detection (pump cavitation and dry-run protection), thermistor input for direct motor winding temperature monitoring (PTC/NTC), ground fault detection, locked rotor/stall detection, excessive starting time protection, motor restart inhibit (thermal memory function), and communication via Modbus RTU for integration with Aramco DCS and SCADA systems.

Saudi Industrial Critical Motor Applications

Large motors protected by the DWE-3 in Saudi facilities include main cooling water circulation pumps in petrochemical plants (typically 45–200 kW), sea water lift pumps in desalination stations (75–500 kW), crude oil transfer pump motors at Aramco terminals (90–400 kW), gas compressor drive motors (200–630 kW), and large HVAC chiller compressor motor starters in industrial and commercial buildings. The consequence of unplanned motor failure in these applications is severe — production loss, safety incidents, and expensive rewind or replacement — making the DWE-3's comprehensive protection capabilities commercially justified.

IEC 60947-4-1 and Saudi Aramco Compliance

The DWE-3 complies with IEC 60947-4-1 for electronic motor starters and protection relays and IEC 60255 for measuring relays. Saudi Aramco Engineering Standard SAES-P-100 specifies electronic motor protection relays for motors above 37 kW, with protection functions including thermal model overload, phase unbalance, phase loss, and thermistor inputs — all provided by the DWE-3. SABIC technical standards for critical rotating equipment similarly mandate electronic protection with Modbus communication for motors driving safety-critical services.

Modbus RTU Communication

The DWE-3's built-in Modbus RTU port allows full integration with plant DCS, SCADA, and PLC systems. Parameters readable via Modbus include phase currents (all three phases), thermal state (% of thermal capacity used), time to trip, time to reset, and fault history log. Writable parameters include protection set points, trip class, and relay reset command. This integration capability aligns with Saudi Aramco's instrumentation and control standards that require all motor protection devices on critical services to report status to the main plant DCS.

Razz Middle East Supply and Engineering Support

Razz Middle East supplies WEG DWE-3 protection relays with full engineering support for Saudi projects: protection relay setting calculations, coordination study inputs, integration wiring diagrams for WEG and third-party MCC panels, and on-site commissioning support including secondary injection testing. DWE-3 relays are stocked in Saudi Arabia for immediate delivery to Aramco, SABIC, SWCC, and SEC projects.