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WEG WHM-R Multifunction Motor Protection Relay
Model: WHM-R
4-hour response · Pricing in SAR · Delivery across all KSA regions
WHM-R — WEG WHM-R Multifunction Motor Protection Relay
The WEG WHM-R Multifunction Motor Protection Relay is a comprehensive digital protection device purpose-built for low and medium voltage induction and synchronous motor protection in industrial applications across Saudi Arabia. Housed in a compact 96 × 96 mm front-panel mount enclosure, the WHM-R integrates thermal overload protection, phase unbalance and loss protection, undercurrent (underload) protection, thermistor input for winding temperature monitoring, Modbus RTU communication, and local LED fault annunciation in a single device that replaces multiple discrete protection relays in the motor protection assembly. The WHM-R is type-tested to IEC 60255-151 thermal overload relay standards and provides protection class 10E thermal curve compliance, covering the vast majority of NEMA and IEC induction motor protection applications without custom curve adjustment.
The WHM-R's thermal model continuously calculates motor thermal state accounting for the fundamental current, negative sequence component (phase unbalance), and ambient temperature via an optional PT100 input, providing a comprehensive picture of winding insulation ageing that a simple bi-metallic overload relay cannot achieve. The relay's phase unbalance protection detects negative sequence voltage components as low as 3%, providing early warning of and trip protection against the supply conditions responsible for the majority of motor burnout failures in Saudi Arabia's industrial facilities, where voltage unbalance on the 380 V distribution network commonly reaches 2–5% during peak demand periods. The thermistor input accepts PTC thermistors embedded in motor windings and provides independent protection against stator temperature exceedances even when current-based thermal models are inaccurate due to non-standard duty cycles.
Motor protection relay specification is a mandatory requirement under ARAMCO's Electrical Protective Device Schedule (EPD) for all motors above 11 kW on new construction projects, and NEC 430 (adopted by most Saudi international contractors) requires protection for all motors above 1 hp. The WHM-R satisfies both requirements at a price point significantly below European competing protection relays, making it the cost-effective choice for the thousands of small and medium motor protection assemblies in pump stations, fan arrays, and conveyor systems across NEOM, SABIC, and NWC projects. The Modbus RTU interface allows integration into plant-wide SCADA or DCS systems, providing motor health data — current, thermal state, fault history — to the control room without additional instrumentation.
Razz Middle East stocks the WHM-R across all current rating variants and provides technical support for relay setting calculations, test procedure documentation, and Modbus integration mapping. Our engineers can prepare motor protection coordination studies aligned with ARAMCO EPD requirements and SABIC Engineering Practices (SEP) electrical protection standards. The WHM-R ships with full English and Arabic documentation. Contact Razz Middle East for a same-day quotation and motor protection relay application guidance.
Technical Specifications
Full specifications for the WHM-R
- Protection Functions
- Thermal overload, phase unbalance, phase loss, undercurrent, thermistor
- Thermal Class
- Class 10E (IEC 60255-151)
- Phase Unbalance Detection
- ≥3% negative sequence
- Thermistor Input
- PTC type, IEC 60947-8
- Communication
- Modbus RTU (RS-485)
- Mounting
- 96×96 mm panel-mount
- Operating Temperature
- -20°C to +60°C
- Auxiliary Supply
- 110–240 V AC/DC universal
Key Features & Benefits
- Comprehensive thermal model incorporating fundamental current, negative sequence, and optional PT100 ambient temperature provides accurate winding insulation ageing calculation beyond simple current-based overload relays.
- Phase unbalance detection threshold of 3% negative sequence provides early warning and trip protection against the most common cause of motor burnout failures in Saudi Arabia's 380 V distribution networks.
- PTC thermistor input provides independent winding temperature protection even when current-based thermal models are inaccurate due to non-standard duty cycles or blocked ventilation on TEFC motors.
- Modbus RTU interface transmits motor current, thermal state, fault log, and trip cause to plant SCADA or DCS, enabling predictive maintenance and fault trend analysis without additional instrumentation.
- Single device replaces multiple discrete relay functions, reducing motor protection panel component count, wiring time, and panel space requirements on new and retrofit motor control centre projects.
- IEC 60255-151 type-tested with Class 10E thermal curve compliance covers NEMA and IEC induction motor applications without custom adjustment, simplifying procurement and setting verification.
Industrial Applications in Saudi Arabia
- Motor protection assemblies in pump motor control centres at NWC water treatment and pumping stations, replacing ageing bi-metallic overload relays with digital protection to reduce motor failure rates.
- Fan motor protection in HVAC motor control centres across commercial, hospitality, and industrial facilities, where phase unbalance protection prevents the single most common motor failure mode.
- Conveyor and material handling motor protection at SABIC and Ma'aden industrial facilities, where Modbus reporting of motor thermal state enables predictive maintenance scheduling.
- Compressor motor protection at oil and gas facilities requiring ARAMCO EPD compliance, where thermistor input provides supplementary protection for high-value motors with embedded temperature sensors.
- Process pump protection in petrochemical plants where undercurrent (underload) protection detects loss of prime and dry running conditions before impeller and mechanical seal damage occurs.
- Mining and quarry motor protection in Wa'ad Al-Shamal and MAADEN facilities where harsh electrical supply conditions make advanced phase unbalance and thermal protection essential.
Industrial Supplier in Saudi Arabia
Get a Quote for the WEG WHM-R Multifunction Motor Protection Relay
We respond within 4 business hours. Send model WHM-R for competitive pricing in SAR with delivery across Saudi Arabia and the GCC.
Frequently Asked Questions — WHM-R
Common questions from buyers in Saudi Arabia and the GCC