High-voltage & low-voltage flameproof units engineered for global hazardous operations.
In modern industrial manufacturing, safety, efficiency, and heavy-duty compliance are non-negotiable. Modern petrochemical complexes, deep underground mines, and volatile processing facilities require advanced drive systems that can withstand extreme mechanical and environmental conditions. Shaanxi Nanfang Motor Technology Co., Ltd. stands as the authoritative premier partner and distributor of Wolong Electric Drive Group Co., Ltd., delivering robust, highly engineered motor technologies designed to eliminate risks in volatile atmospheres.
When engineering motors for hazardous locations, our design architecture centers on mitigating the risks of internal explosions igniting surrounding flammable gases, dusts, or vapors. To guarantee this, our technical portfolios feature diverse ranges of protection concepts including flameproof (Ex d), increased safety (Ex e), and non-sparking (Ex n). By addressing thermal containment, precise flame-path engineering, and high structural integrity, we supply systems that minimize operational downtime while maximizing protection protocols.
"The core function of an OEM flameproof motor is containment and cooling. It is designed to withstand the internal pressure of an explosion without cracking, fracturing, or propagating flames into external zones, maintaining strict compliance with the ATEX Directive 2014/34/EU and the international IECEx guidelines."
The structural scale and capability of Wolong's international operations and development centers.
Founded in 1984 and listed on the Shanghai Stock Exchange in 2002 (code SH600580), Wolong Electric Drive Group has grown into an international powerhouse in electric drive and automation solutions. Today, the group operates 3 major manufacturing bases, 39 advanced factories, and 3 global research and development centers. As a key strategic link, Shaanxi Nanfang Motor Technology Co., Ltd. brings this robust manufacturing network to global heavy industries, ensuring seamless engineering coordination, international product supply, and local field support.
Wolong's growth is driven by technological integration and strategic international acquisitions. By incorporating some of the world's most respected names in electric machinery, Wolong has combined century-old engineering experience with modern, high-volume production capabilities.
In 2011, Wolong acquired a 97.94% stake in the Austrian ATB Group, one of Europe's top three motor manufacturers. This acquisition integrated renowned sub-brands like Morley—highly regarded for heavy-duty underground coal mining machinery—and Laurence Scott, a specialist supplier of low-starting-current motors for naval vessels and nuclear power plants. This integration significantly enhanced our technical capabilities in high-voltage, high-reliability safety motors.
Brook Crompton brought over a century of experience in motor design and innovation to the group, particularly in high-efficiency low-voltage and medium-voltage AC motors. In parallel, Germany's Schorch, founded in 1882, contributed its deep expertise in drive systems for oil & gas, steel production, water management, and critical infrastructure tunnels, reinforcing our high-voltage flameproof engineering capabilities.
In 2015, China's largest research and production base for explosion-proof motors, CNE (Nanyang Explosion Group), joined the group. This was followed in 2018 by the acquisition of General Electric (GE)'s commercial and industrial motor division. This combination of GE's heavy industrial experience with CNE's explosion-proof engineering has established the group as a leading global authority in explosion-proof electric drives.
Deep engineering details of critical components that define flameproof performance.
Our rotors are engineered to withstand continuous thermomechanical stress. We utilize squirrel cage designs with cast aluminum rotors, produced via centrifugal or high-pressure die-casting to eliminate internal air pockets. For large-frame, high-output medium and high-voltage motors, copper-bar rotors with precision-welded end rings and protective high-speed retaining rings are used, ensuring mechanical stability and minimizing vibration under varying loads.
Stator winding longevity relies on effective dielectric insulation. Using polyester film backed with glass cloth and high-mica-content tapes, we construct high-integrity stator coils. The wound core undergoes a computer-controlled Vacuum Pressure Impregnation (VPI) process, drawing resin deep into the windings before curing. This creates a solid block with high moisture resistance, mechanical rigidity, and excellent thermal dissipation.
Our cast iron and fabricated steel frames are optimized using dynamic digital twin simulation platforms. We run multi-physics analyses to evaluate structural stiffness, cooling air flows, and vibrational modes. The resulting enclosures offer high structural redundancy, minimal resonant vibration, and excellent heat dissipation, keeping stator hotspots cool and ensuring reliable containment in hazardous environments.
A major design challenge for explosion-proof motors is reducing fan-generated noise. Our low-noise cooling systems feature aerodynamically optimized fan shrouds with side air inlets and integrated acoustic dampening materials. This design reduces aerodynamic drag, minimizes flow turbulence, and lowers overall noise levels. The assemblies are rated IP22 or higher, preventing foreign object ingress and ensuring safe operation.
Wolong drive systems are certified for use across global jurisdictions.
Nemko / ATEX
CSA
CE
CCC
SABS
TESTSAFE
Different regions apply specific regulatory standards to equipment in explosive atmospheres. Our engineering and manufacturing processes conform to these frameworks, ensuring certified quality and global market access:
The industrial drive market is transitioning toward higher efficiency, integrated condition monitoring, and intelligent variable frequency controls. At Wolong, we are investing in these technologies to deliver next-generation explosion-proof drive solutions:
Developing ultra-premium efficiency Permanent Magnet (PM) synchronous motors that reduce energy losses by up to 50% compared to standard induction motors, while keeping operating temperatures lower.
Designing motors optimized for Variable Frequency Drive (VFD) operation, preventing insulation degradation from high voltage spikes and suppressing bearing shaft currents.
Integrating non-invasive, intrinsically safe (Ex i) smart sensors to monitor temperature, vibration, and magnetic flux, enabling predictive maintenance before failure occurs.
By linking engineering resources across China, Europe, and the Americas, we ensure that new designs are thoroughly simulated, tested, and certified before commercial launch. This approach delivers reliable, high-performance, and compliant motors to the global market.
Where Wolong high-efficiency flameproof motors are deployed in harsh environments.
Powering pipeline compressors, crude oil pumps, and cooling fans in refineries where explosive hydrocarbons (Group IIB/IIC gases) are present.
Driving longwall shearers, continuous miners, and main ventilation fans in methane-rich coal environments, using high-torque Morley motor designs.
Supplying low-starting-current cooling pumps and auxiliary drives for nuclear and conventional thermal plants, drawing on Laurence Scott design histories.
Driving thrusters, deck machinery, and LNG compressors on cargo ships, gas carriers, and offshore platforms under high salt spray and moisture conditions.
Each application has specific electrical and mechanical requirements. For example, maritime installations demand high corrosion protection (C5-M paint systems) and marine-certified bearings, while chemical applications require chemical-resistant coatings and specialized shaft seals (IP56 or IP66). In contrast, underground mining requires robust steel frames and water-cooled enclosures to dissipate heat in tight spaces. At Wolong, we customize our drive designs to match these specific operating conditions.
Answers to common technical and certification questions for process engineers and procurement teams.
Flameproof (Ex d) enclosures are designed to contain an internal explosion without damage and prevent the ignition of surrounding hazardous gases through engineered flame paths. Increased Safety (Ex e) motors, however, focus on preventing sparks, arcs, or hot surfaces from forming during operation, relying on strict component tolerances and temperature monitoring rather than containment.
No. The motor and VFD must be certified as a matched system, or the motor must be equipped with thermal sensors (such as PTC thermistors) connected to the VFD's safety trip circuit. This setup ensures that voltage harmonics from the drive do not cause the motor's surface temperature to exceed its rated class limit (e.g., T4).
Higher altitudes have thinner air, which reduces cooling efficiency. For installations above 1000 meters, flameproof motors must either be derated or upgraded with class H insulation, or designed with larger frames to maintain safe operating temperatures and comply with site safety standards.
VPI replaces air voids within the stator windings with a cured resin block. This minimizes insulation-damaging vibrations, improves heat transfer from the coils to the frame, and prevents the ingress of moisture or corrosive chemicals, protecting the motor in aggressive industrial atmospheres.
Group IIC is the most demanding gas category, covering highly volatile gases like hydrogen and acetylene. A motor certified for Group IIC has tighter flame path tolerances and can be safely operated in environments containing Group IIA (methane/propane) and IIB (ethylene) gases as well.
High-efficiency drive units and variable-frequency systems for heavy duty applications.
NANFANG
