一、Technical Principle: Harness the power of permanent magnets to ride the wind.
Voofu Permanent Magnet Direct-drive Motor for Air-cooled Island (WF-KD Series) is an engineering masterpiece integrating permanent magnet synchronous motor and direct-drive design. Its core working principle can be summed up in three aspects: magnetic field, rotation and direct drive.Magnetic Field Establishment – Permanent magnets replace excitation currentThe surface of the rotor core is embedded with rare-earth permanent magnet materials with high magnetic energy product and high coercivity, such as N45UH neodymium-iron-boron (NdFeB). Once magnetized, the permanent magnets produce a constant magnetic field permanently without electric excitation. This is fundamentally different from conventional asynchronous motors that generate magnetic fields by drawing power from stator induced current. It features more stable magnetic field, lower energy consumption and faster response.The stator consists of a laminated silicon steel core and three-phase windings. When connected to a frequency converter, it generates a rotating magnetic field whose synchronous speed follows the formula:
\(n_1 = 60f / p\)
(f = power frequency; p = number of pole pairs)Electromagnetic Torque – Driving force generated by magnetic field interactionThe interaction between the stator rotating magnetic field and the rotor permanent magnetic field follows the rule that unlike poles attract and like poles repel, thus producing driving torque: \(T = K_t \cdot \Phi \cdot I\) (\(T\propto\Phi\cdot p\cdot I\)). Here, \(\Phi\) stands for magnetic flux of permanent magnets and p for the number of pole pairs.With multi-pole design (increased p) and variable frequency control (reduced f), the motor can deliver high torque at extremely low speeds. More pole pairs lead to lower synchronous speed and higher torque, which perfectly satisfies the low-speed and high-torque requirements of air-cooling fans at 10~500 r/min.Direct Drive Implementation – Remove reducers for streamlined transmissionTraditional solutions adopt a two-stage transmission composed of asynchronous motor and reducer. By optimizing pole pairs and frequency conversion control, Voofu permanent magnet motors directly output low-speed high torque. The motor shaft is directly connected to the fan impeller hub, eliminating all intermediate transmission components.It supports stepless speed regulation within the range of 0~110% and adopts sensorless vector control. Its starting current is only 1.5~2 times the rated current, far lower than the 5~7 times of asynchronous motors, resulting in negligible impact on the power grid.
二、Product Advantages: Dominant in six dimensions and taking an all-round lead
| Advantage Dimensions | Specific manifestations | Data support |
|---|---|---|
| Extreme Energy Efficiency | Eliminate the reducer to reduce transmission loss. The motor achieves an efficiency of up to 95% and has obtained the National Class 1 Energy Efficiency Certification (GB 30253-2013). | Field measurement at a thermal power plant in Inner Mongolia: An annual saving of 133,000 yuan per unit |
| Remarkable energy-saving effect | It achieves more remarkable energy-saving effect under light load, with an overall energy-saving rate ranging from 20% to 76.9%. | A Power Plant in Shanxi: Energy Saving Rate Reaches 76.9% Under Low-Load Operation |
| Maintenance-free | No reducer oil leakage, no gear wear, and no lubrication required. Only regular maintenance for bearings is needed. | Annual maintenance cost reduced by 26,000 yuan per unit, with a service life of over 30 years |
| High reliability | Protection class IP67, fully enclosed design. The permanent magnets of the rotor can withstand temperatures up to 180℃, and the stator adopts a dual process of "vacuum pressure impregnation + epoxy resin vacuum potting". | Adapt to harsh environments such as high temperature, humidity and dust |
| Lightweight and compact | The total machine weight is less than 1.8 tons and the diameter is less than 900mm, bringing no additional load impact on the air-cooled island support. | No need to modify the steel structure; ready for immediate installation and use |
| Soft Start | Soft start with buffering, overload protection capacity of 2.0~2.5 times, and automatic air-gap slip protection upon instantaneous stall. | The system vibration is greatly reduced, extending the service life of peripheral equipment. |
One-sentence summary: Higher efficiency, lower maintenance, longer service life and lower costs — this is not an upgrade, but a revolution.
三、Application Scenarios: Wherever the wind blows, direct drive is achievable.
Voofu Permanent Magnet Direct-drive Motors for Air-cooled Islands have been successfully retrofitted in numerous projects across power, metallurgy, chemical, cement, coal, iron and steel, military and other industries. Its main application scenarios are as follows:
Air-cooled island fans in power plants (Core application: thermal power plants)
A typical 300MW unit is equipped with 30 air-cooling fans, whose power consumption accounts for 7%~11% of the plant auxiliary power. Take the retrofitting of Unit #1 at a power plant in Shanxi as an example:
| operating condition | Speed range | Energy saving rate |
|---|---|---|
| High load | 69~77 rpm | 5.8% |
| Medium load | 35~60 rpm | 31% |
| low load | 15~30 rpm | 76.9% |
Each unit is equipped with 12 air-cooled fans, and the two pilot units generate an annual economic benefit of approximately 266,000 yuan.
More industrial scenarios
Heavy-duty and low-speed equipment such as mills, powder separators, agitators, belt conveyors, elevators, compressors and water pumps can all adopt the Wolf permanent magnet low-speed direct drive solution, with an energy-saving rate generally ranging from 20% to 50%.
四、Honor Endorsement: Nationally Recognized, Strength Beyond Doubt
Selected into the First Batch of Advanced and Applicable Technologies by MIIT (Gong Ke Han [2025] No. 99)
National High-tech Enterprise / National Specialized, Refined, Differential and Innovative "Little Giant" Enterprise
Core technology rated as Domestic Leading in the scientific and technological achievement appraisal organized by MIIT (Certificate No.: 202034ZK4474)
National Class 1 Energy Efficiency Certification / National Explosion-proof Certification / National 3C Certification
Numerous application cases, services covering major industrial regions nationwide
Voofu Permanent Magnet Direct-drive Motor for Air-cooled Island – Remove the reducer and make every kilowatt-hour count. Against the backdrop of the national dual-carbon strategy, this is more than just a motor. It serves as the core driver for the green transformation of traditional energy sectors.
Feel free to contact Voofu Permanent Magnet for customized energy-saving solutions tailored to your on-site operating conditions. Let permanent magnet technology deliver sustained power to your equipment!
