Explore our high-performance low-voltage and high-voltage frequency-controlled electric drive configurations engineered for hazardous, industrial, and heavy-duty maritime environments.
In the modern landscape of high-performance industrial drive technology, the transition from traditional line-start induction machinery to variable speed systems is no longer merely an option—it is a critical imperative. As global manufacturing mandates pivot toward aggressive decarbonization, energy reduction, and smart plant infrastructure, the role of a Frequency Controlled Motor (often referred to as a VFD-fed induction or Permanent Magnet Synchronous Motor) becomes highly vital. These specialized electric motors are structurally and electromagnetically engineered to withstand the unique mechanical and electrical stresses induced by pulse-width modulation (PWM) inverter waveforms.
Operating a standard motor at variable speeds without proper insulation and winding architectures inevitably leads to premature insulation degradation, rotor fatigue, and catastrophic bearing failures due to common-mode shaft currents. By partnering with a premier Chinese enterprise specializing in precision-engineered frequency-controlled drives, global procurement departments and engineering EPCs gain access to state-of-the-art motor structures. These motors are optimized for low-vibration, high-torque, and high-efficiency performance across their entire operational speed spectrum, satisfying both the most demanding mechanical specifications and the stringent global environmental compliance frameworks.
Shaanxi Nanfang Motor Technology Co., Ltd is the authorized premier distributor of Wolong, specializing in deploying heavy-duty, highly efficient, and explosion-proof variable-speed motors globally.
Wolong Electric Drive Group Co., Ltd. was established in 1984 and successfully listed on the Shanghai Stock Exchange in 2002 (code SH600580). Over nearly four decades of rapid scaling and technical iteration, Wolong has solidified its status as an undisputed giant in the international motor drive sector. The enterprise currently operates 3 primary manufacturing bases, houses 39 state-of-the-art factories, and manages 3 advanced global Research and Development centers.
Wolong’s global strategic expansion relies on the synergy of century-old engineering design combined with high-volume, precision manufacturing capabilities in China. By focusing on motors and control integration, Shaanxi Nanfang Motor delivers Wolong's superior technologies to customers worldwide, guaranteeing localized service and rapid deployment for highly customized EPC projects.
Leveraging world-class manufacturing pipelines and rigorous quality management controls to deliver high reliability, energy savings, and hazardous area compliance.
We provide full explosion-proof, flameproof, and increased safety designs (Ex d, Ex e, Ex p, Ex n) verified by leading certification bodies for petroleum, petrochemical, and mining industries.
Available in premium high-efficiency ratings (IE3, IE4, and ultra-premium IE5 levels), including Permanent Magnet Synchronous Motors (WEPM series) to slash operation overheads.
From low-voltage marine motors to massive high-voltage positive pressure industrial variants, our portfolio accommodates diverse standard and hazardous environment setups.
Discover how our global network, research structures, and industrial lineage combine to secure process optimization and risk mitigation.
Wolong has established specialized motor and drive control R&D centers across three engineering hubs: China, Europe, and Japan. Operating in tandem with the Shanghai Central Research Institute, our engineering staff works on high-efficiency topologies, variable-frequency insulation performance, and structural dynamics. By implementing multi-physics simulation platforms, our frequency-controlled motors reach leading metrics in torque density, reliability, and acoustic emission reduction, creating immediate values for our global client base.
The Wolong Group commands a powerful collection of domestic and century-old international motor brands. This includes Nanyang Explosion-proof (CNE)—China's preeminent manufacturer of explosion-proof motors—alongside internationally recognized Western names: Brook Crompton, Morley, Laurence Scott, Schorch, and ATB. Under unified management, these brands integrate classic design methodologies with cost-effective, high-volume production structures, creating the ultimate blend of European engineering heritage and Chinese manufacturing efficiency.
Our variable-speed explosion-proof motors are designed to operate safely in the presence of volatile dusts and combustible gases. Engineered with high safety margins, durable cast frames, and robust terminal enclosures, they possess extensive certifications, including ATEX, IECEx, CU-TR, UL, CSA, DNV, and SABS. These motors are trusted by global petrochemical majors and mining enterprises in demanding applications such as coal mine ventilation, slurry pumping, and offshore drilling platforms.
Wolong's growth strategy relies on acquiring and scaling legendary industrial brands, bringing centuries of consolidated technical experience under one robust global umbrella.
Wolong acquired a 97.94% stake in the Austrian ATB Group, one of Europe's top three motor manufacturers. This historic transaction integrated Morley (130 years of underground coal mining expertise) and Laurence Scott (renowned for custom low-starting-current naval/nuclear generators) into the Wolong system. The integration significantly expanded Wolong's presence in international energy markets.
German brand Schorch (established 1882) joined Wolong, offering specialized systems for oil and gas, shipbuilding, and water treatment. In parallel, Brook Crompton brought over a century of motor design expertise, accelerating the production of premium low-voltage, medium-voltage, and high-efficiency induction systems globally.
To lead the global vibration motor market, Wolong established strategic industrial partnerships with OLI, combining industrial vibrators, Ex sensors, and robust speed controller technologies to service bulk material handling and mining separation plants globally.
CNE, China's largest scientific research and manufacturing base for explosion-proof motors, officially integrated into the Wolong Group. This consolidation strengthened the company's R&D capabilities for high-voltage flameproof, positive-pressure, and high-efficiency safety motors.
Wolong signed a major acquisition agreement covering General Electric's commercial and industrial motor division. This partnership added GE's design heritage and US NEMA market experience, reinforcing Wolong's global reach and technical capability in the Americas.
Every component is designed to withstand the electrical, thermal, and mechanical stresses of variable frequency drive operation.
Our rotors are engineered for minimal inertia and optimized slip behavior. We utilize advanced centrifugal and high-pressure die-casting techniques for pure aluminum squirrel-cage configurations. This process integrates the conductor bars and end rings into a single piece, eliminating joint resistance. For large, high-capacity, or high-speed applications, we employ high-grade copper bar designs. These feature precision induction welding and custom end-ring retaining mechanisms, allowing the rotor assembly to withstand continuous starting torque transients and thermal variations under VFD speed control.
PWM inverter waveforms generate high voltage spikes (dV/dt) that can degrade standard motor windings. To prevent this, our coils are wrapped with high-quality mica tape (low or medium-powder variants) reinforced with polyester film and glass cloth. The completed stator assembly undergoes Vacuum Pressure Impregnation (VPI). This process fills air pockets with high-grade varnish, creating a rigid insulation structure. The resulting stator exhibits excellent dielectric strength, moisture resistance, and thermal conductivity, enabling long-term reliability under continuous variable speed operation.
Variable speed operation can excite natural frequencies, leading to structural resonance. We address this using a digital design platform to conduct 3D finite element analysis (FEA) and fluid multi-physics simulations. The cast-iron or fabricated steel frames feature high mechanical stiffness and optimized cooling rib geometries. This design provides structural margin, dampens vibrations, and optimizes heat dissipation, maintaining a low temperature rise across the entire operational speed range.
When induction motors are operated via VFDs, high-frequency harmonics can increase overall acoustic emissions. Our motors are equipped with low-noise ventilation hoods. These systems integrate a fan cover body, air guide cylinder, silencer plates, and sound-absorbing composite materials. The aerodynamic flow paths minimize energy loss and suppress windage noise. Rated at IP22 (or higher upon project specifications), these assemblies prevent direct contact with rotating elements while keeping the operational sound output well within strict municipal and industrial HSE regulations.
Our engineering, testing, and production workflows conform to strict international frameworks, streamlining site integration and regulatory approvals.
Our manufacturing sites utilize an ISO 9001 certified Quality Management System. For North America, we perform exhaustive efficiency, starting current, torque, and insulation testing to meet NEMA performance standards, securing UL and CSA certificates. For offshore and marine duties, our low-voltage three-phase motor systems carry DNV Type Approval certificates, showing they are verified to withstand corrosive salt spray, high humidity, and continuous tilt environments.
For applications in hazardous areas, our motors hold full ATEX and IECEx approvals. We have also acquired the TESTSAFE certification—the primary coal mining and industrial product regulatory standard in the Southern Hemisphere. This approval streamlines the deployment of Chinese-built explosion-proof motors into mining operations in Australia and adjacent Commonwealth regions.
Sourcing variable-frequency motors from China offers significant advantages, particularly regarding supply chain vertical integration. From high-grade electrical steel laminations and ultra-pure electrolytic copper windings to precision cast iron housings and custom drive systems, the entire ecosystem is located in close proximity. This concentration of raw material processors, specialized component manufacturers, and testing laboratories shortens lead times for both standard configurations and highly customized orders.
By pairing Wolong’s global design heritage (derived from ATB, Schorch, and GE) with China's manufacturing speed, Shaanxi Nanfang Motor delivers cost-effective, high-performance solutions. The resulting cost savings allow us to use premium materials—such as high-grade Class H insulation systems, vacuum-pressure varnishes, and insulated bearings—without charging premium prices. This structure lowers the Total Cost of Ownership (TCO) for global operators while maintaining high performance and reliability.
Every motor undergoes thorough factory testing before dispatch. This testing regimen includes no-load and full-load testing, dynamic balancing, stator resistance checks, vibration spectrum analysis, and insulation testing. These QA procedures ensure that the final equipment meets international requirements, minimizing commissioning delays and troubleshooting on-site.
By integrating structural design, manufacturing control, and testing protocols, we guarantee that every frequency-controlled motor operates reliably in demanding industrial applications.
Our frequency-controlled motor systems provide reliable, efficient operation in demanding applications across key global industries.
Powering pipeline pumps, heavy compressors, and refinery air-coolers. Our explosion-proof and positive-pressure motors operate safely in Zone 1 and Zone 2 hazardous areas.
Driving long-distance belt conveyors, ventilation fans, and dewatering pumps. Designed with durable flameproof casings to withstand coal dust and mechanical impact.
Powering winches, thrusters, and ballast pumps. Built with corrosion-resistant finishes and DNV certifications to withstand salt-spray and marine environments.
Powering smoke extraction fans and chiller pumps. Engineered for high-temperature resistance and variable speed control to match system demand.
Rising energy prices and strict regulations are accelerating the transition from IE3/IE4 asynchronous machines to IE5 Permanent Magnet Synchronous Motors (PMSMs). These motors utilize neodymium magnets to eliminate rotor copper losses, maintaining high efficiency even at partial loads and low speeds.
Modern operations rely on digital connectivity. Incorporating vibration and thermal sensors onto the motor frame allows for real-time condition monitoring. This data enables predictive maintenance, helping operators identify and address issues before they cause costly downtime.
The development of Wide Bandgap (WBG) semiconductors like Silicon Carbide (SiC) in VFDs enables higher switching frequencies. This requires motors with advanced stator insulation systems to withstand faster voltage rise times (dV/dt) and prevent corona discharge.
Detailed answers to key technical questions regarding the selection, operation, and maintenance of frequency-controlled motors in demanding industrial environments.
Standard Direct-On-Line (DOL) motors are designed for sinusoidal power supplies. In contrast, Variable Frequency Drives (VFDs) use Pulse Width Modulation (PWM) to control motor speed. This high-frequency switching generates fast-rising voltage pulses (high dV/dt) and reflected wave phenomena, especially over long cable runs. These voltage spikes can stress the winding insulation, leading to corona discharge and premature dielectric breakdown. Specialized frequency-controlled motors utilize corona-resistant magnet wire, advanced phase insulation, and Vacuum Pressure Impregnation (VPI) with high-grade resins to withstand these electrical stresses.
The voltage imbalance in VFD outputs can induce capacitive voltages on the motor shaft. If these voltages exceed the dielectric strength of the bearing grease film, they discharge through the bearings, causing electrical discharge machining (EDM). This leads to pitting, fluting, and bearing failure. We prevent this by installing insulated bearings (typically on the non-drive end) or hybrid ceramic bearings for motors above 110 kW. Additionally, we integrate grounding rings or carbon brushes on the shaft to provide a low-impedance path to ground, redirecting harmful currents away from the bearings.
Standard motors are typically Totally Enclosed Fan Cooled (TEFC, IC411), relying on a shaft-mounted fan. At low operating speeds, the airflow generated by the shaft fan drops significantly, reducing heat dissipation while the motor may still output full rated torque. For applications requiring continuous operation at low speeds, we recommend using a forced ventilation configuration (TEFV, IC416). This setup features an auxiliary constant-speed fan that maintains constant cooling airflow regardless of the main motor shaft speed, preventing thermal overloading.
Yes, provided the motor is certified as a system alongside its matched VFD. For Zone 1 hazardous environments, we utilize flameproof (Ex d / Ex db) or pressurized (Ex p) enclosures. The certification process verifies that the motor's surface temperature remains below the auto-ignition threshold of surrounding gases, even during overload conditions. Testing is typically performed with the specific drive to account for VFD-induced harmonic heating.
Induction motors are robust, cost-effective, and easy to maintain, making them suitable for most standard variable speed applications. However, they incur rotor I2R losses. Permanent Magnet Synchronous Motors (PMSMs), such as the WEPM series, feature permanent magnets in the rotor. This design eliminates rotor losses, enabling high torque density, compact size, and IE5-level efficiency, particularly under partial load conditions. Note that PMSMs require a VFD for operation and cannot start direct-on-line.
We collaborate closely with clients to review datasheets, drawing templates, and electrical specifications. As Wolong's authorized distributor, we coordinate production scheduling directly with the factories. This direct communication, combined with China's integrated supply chain and raw materials reserves, allows us to optimize lead times for custom projects (such as special voltages, marine class modifications, or custom shaft extensions) while ensuring full compliance with international engineering standards.
Explore our high-performance low-voltage and high-voltage frequency-controlled electric drive configurations engineered for hazardous, industrial, and heavy-duty maritime environments.
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