Engineered to operate reliably in explosive and severe industrial environments
Shaanxi Nanfang Motor Technology Co., Ltd. serves as the premier authorized distributor of Wolong Electric Drive Group Co., Ltd. Founded in 1984 and listed publicly in 2002 (SH600580), Wolong has advanced into a top-tier player in global motor technology and automation systems.
With a massive footprint including 3 major manufacturing bases, 39 state-of-the-art factories, and 3 localized global R&D centers, Wolong leverages advanced engineering resources to customize Medium Voltage (MV) Ex motors that deliver optimized efficiency, safe containment in explosive atmospheres, and a lower total cost of ownership.
Understanding the engineering details that make Wolong Medium Voltage Ex Motors standard-setters for reliability
The rotor construction incorporates advanced squirrel-cage technology. Cast aluminum rotors are produced via high-pressure centrifugal casting or precision die-casting. The molten pure aluminum flows into the slots of the silicon steel core, forming a single-piece component that integrates rotor bars and end-rings. For high-output, heavy-duty applications, high-grade copper bars are manually inserted into the slots, followed by precise induction-brazing to the end rings. Retaining rings are fitted on high-speed configurations to counteract centrifugal stresses, ensuring low residual vibration levels.
Stator coils are wrapped with high-quality, glass-fiber-reinforced polyester film and structured using high-content, low-powder mica tape. The fully wound stator undergoes our proprietary Vacuum Pressure Impregnation (VPI) cycle. By removing residual air pockets within the insulation layers and replacing them with premium epoxy resin under high pressure, the system secures maximum dielectric strength, resistance to humidity, mechanical stability, and thermal conductivity.
Engineered through multi-physics simulation platforms, our high-tensile cast iron or heavy structural welded steel plate frames provide high stiffness and structural damping. The cooling rib design optimizes airflow distribution and dissipation pathways, ensuring lower temperature rises. Heavy structural redundancy guarantees resistance to physical impacts in mines and refineries while maintaining safe isolation frequencies.
Operating large electric machinery in indoor environments presents noise challenges. Our low-noise fan cover system integrates an optimized air-guiding cylinder, protective inlet mesh (rated IP22), and sound-absorbing lining plates. The side-entry air configuration reduces structural obstacles behind the fan, mitigating energy losses and turbulence. Integrated noise-damping lining materials absorb sound waves, keeping emissions well within safety levels.
Engineered solutions designed to meet hazardous industry challenges and safety regulations
Fully compliant and third-party certified for explosive hazardous locations worldwide, supporting ATEX, IECEx, CSA, UL, CU-TR/EAC, SABS, and TESTSAFE.
Supports high motor efficiency classes up to IE4 and IE5. Includes permanent magnet solutions that reduce power consumption in heavy-duty setups.
A complete line of low, medium, and high-voltage three-phase asynchronous and synchronous motors for petrochemicals, mineral processing, and power generation.
To establish itself as a global manufacturer of AC motors & drives, Wolong pursued strategic international acquisitions. In 2011, Wolong acquired 97.94% of the Austrian ATB Group (ATB Motor), a prominent European motor manufacturer. This transaction brought Morley (specializing in underground coal mining equipment) and Laurence Scott under the Wolong umbrella.
The Morley brand possesses over 130 years of history in design for underground coal mining, while Laurence Scott remains a recognized name in engineering low starting current electrical drives and generators for nuclear power facilities and naval vessels.
This expansion continued with the acquisition of Brook Crompton, a brand known for energy-efficient low, medium, and high-voltage motors, followed by Schorch in 2011, which serves key projects in oil, gas, and power generation.
Furthermore, Wolong's partnership with OLI has established a footprint in the vibration motor market, while the acquisition of Nanyang Explosion-Proof Group Co., Ltd. (CNE) in 2015 created one of China's largest explosion-proof research and manufacturing bases. The acquisition of General Electric's (GE) Commercial and Industrial motor division in 2018 added further engineering depth to Wolong's product offerings.
Acquired ATB Group, including Laurence Scott and Morley, alongside industrial manufacturer Schorch.
Integrated China's largest research and manufacturing base for explosion-proof drives.
Acquired GE's commercial and industrial motor division, integrating premium design standards.
A look inside the design, winding, and assembly processes that build each explosion-proof drive
Ensuring compliance with major international standards to allow seamless deployment across hazardous regions
Nemko/ATEX
CSA
CE
CCC
SABS
TESTSAFE
Wolong operates under a unified marketing strategy that includes obtaining global product certifications. This allows our products to clear international trade barriers and meet specific local project parameters.
Operating as an OEM provider requires managing production capacity, raw material sourcing, and quality control. Wolong's 39 manufacturing plants in China and globally leverage automated production systems and regional supplier networks.
By handling operations in-house—including casting housing frames, stamping laminations, processing copper wire, and performing VPI cycles—we maintain control over lead times and quality. Our volume purchasing of silicon steel and copper wire provides pricing advantages that we pass on to our global customers.
Procurement teams at engineering firms (EPCs) look for suppliers that offer technical support, drawing verification, and manufacturing capacity. We provide detailed 2D/3D CAD models, data sheets, and calculation reports to simplify the engineering integration process.
Our manufacturing setup allows us to construct custom shaft extensions, paint to specific environmental ratings (C5-M for offshore marine), integrate PT100 temperature sensors, and supply certified space heaters for tropical locations.
Industrial electric motors are critical assets that require timely field support. Our network of global distributors, certified workshops, and service partners assists with commissioning, routine maintenance, and repair work.
Before shipment, each motor undergoes testing at our facility. This includes winding resistance, vibration measurements, no-load operations, and insulation verification. Full-load dynamic tests and temperature tests are also available on our test stands upon project request.
The industry is moving toward variable frequency drive (VFD) speed control to optimize energy use. Our variable-frequency motors (such as the WEBP3 and TBVF series) feature insulation designs that resist voltage spikes caused by high-frequency switching.
We also offer insulated bearings and grounding brushes on the non-drive end to prevent electrical erosion, extending the operating life of the motor system.
How our explosion-proof motor configurations are utilized in specific field applications
Used to drive pipeline transport pumps, high-pressure gas compressors, and refining process fans. Our flameproof (Ex d) and increased safety (Ex ec) motors isolate internal ignition sources to maintain safety in environments with explosive hydrocarbon vapors (Group IIA, IIB, IIC).
Designed for coal shearers, armored face conveyors (Morley YBSD series), and extraction ventilation fans. These flameproof Group I motors are built to handle coal dust, moisture, and high starting torque requirements.
Driving boiler feed pumps, primary air fans, and water intake pumps. Features like brushless excitation (TAW series) and positive pressure housing design (TZYW series) provide reliability in power generation operations.
Technical guidance on selecting, operating, and maintaining medium voltage explosion-proof motors
Ex d (Flameproof) enclosures are designed to contain any internal explosion, preventing the ignition of gases or vapors in the surrounding atmosphere. The joints and flame paths are dimensioned to cool escaping gases below their ignition temperature.
Ex e (Increased Safety) relies on design measures to prevent electrical arcs, sparks, or hot spots under normal operation and expected overload conditions. The design utilizes insulation clearances, temperature monitoring, and robust electrical connections.
The VPI process helps eliminate voids within the stator insulation system. By pulling a vacuum, air and moisture are extracted from the mica winding tape. Epoxy resin is then introduced under high pressure, filling all remaining spaces.
This process forms a solid insulation barrier that improves dielectric strength, heat transfer from the coils to the frame, moisture resistance, and mechanical protection against vibration.
When operating with a Variable Frequency Drive (VFD), the motor's insulation must be designed to withstand high voltage rise rates (dv/dt) caused by carrier frequency pulses.
To prevent bearing damage from circulating shaft currents, we recommend installing insulated bearings on the non-drive end and using a shaft grounding ring. Embedded winding and bearing RTDs are also recommended to monitor thermal conditions under low-speed operation.
Wolong maintains certifications with regional testing bodies, such as Australia's TestSafe. This certification aligns Chinese manufacturing and design standards with Australian mining and industrial safety requirements, facilitating standard compliance and imports for regional projects.
Engineered for high-efficiency variable speed application setups in industrial processes
NANFANG
