一、Technical Principle - Torque Transmission via Air Gap, Oil Cooling for Protection
Voofu Horizontal Oil-Cooled Permanent Magnet Governor (Model Series: WF-TW) is a revolutionary transmission device that transmits torque through air gaps. It fundamentally changes the conventional rigid transmission configuration of "motor + reducer + coupling". Its core design replaces mechanical connections with magnetic fields and fan cooling with thin oil cooling.
Three-step transmission, torque generated without physical contact
Step 1: Establishment of permanent magnetic field
The high-precision permanent magnet rotor assembly fitted with high-strength rare-earth NdFeB permanent magnets is rigidly connected to the load shaft to form the driven rotor, which generates a strong constant magnetic field. No electric excitation is required, eliminating excitation loss at the source.
Step 2: Magnetic generation via eddy current induction
When the motor runs, it drives the composite conductor rotor (connected to the motor shaft) to cut magnetic lines at high speed within the magnetic field of permanent magnets, generating eddy currents inside the conductor disc. These eddy currents induce a magnetic field on the conductor rotor. The attractive and repulsive forces between the induced magnetic field and the permanent magnetic field drive the driven rotor to rotate synchronously. There is no mechanical contact between the motor and the load, while torque is transmitted across the air gap.
Step 3: Air gap adjustment for stepless speed regulation
An electric actuator drives the worm and worm gear assembly to precisely adjust the air gap between the driving rotor and the driven rotor.
| Air gap state | Magnetic field strength | Induced magnetic field | Transmit torque | Load speed |
|---|---|---|---|---|
| Small air gap | strong | strong | big | high |
| Large air gap | weak | weak | small | low |
This enables stepless speed regulation within the range of 30% to 97%. It can also connect to the DCS system or support PID control via the input 4~20mA signal, so as to accurately match the load requirements under different working conditions.
Oil Cooling Innovation: Thin Oil Spraying, Three Benefits at Once
Different from early water-cooled models plagued by water-oil leakage and bearing emulsification, Voofu adopts an innovative disc-type symmetric oil-cooled structure. The main body of the permanent magnet equipment is fully sealed inside the outer sleeve, with continuous oil spray supplied by the thin oil station.
Cooling: Oil directly acts on core heat-generating areas, ensuring reliable heat dissipation even for units up to 5000kW.
Lubrication: The bearings of the speed regulating mechanism are forcibly lubricated, enabling continuous operation for over 5 years.
Anti-corrosion: The oil film isolates moisture. Disassembly inspection after 6 years of operation proves the interior remains as clean as new.
The complete system consists of four parts: oil-cooled permanent magnet governor, permanent magnet junction box, thin oil station and thin oil station terminal box. It features plug-and-play performance and is highly suitable for retrofitting projects.
二、Product Advantages — Six-dimensional Superiority, Comprehensive Leadership
| Advantage Dimension | Traditional solution | Voofu Horizontal Oil-Cooled Permanent Magnet Governor | improvement range |
|---|---|---|---|
| Energy-saving efficiency | Low valve efficiency and severe waste during constant-speed operation | Pure mechanical transmission, no power consumption, speed adjustment as required | Power saving rate: 20% ~ 50% |
| System vibration | Rigid connection, vibrations are transmitted directly | Non-contact flexible connection isolates vibration transmission | Vibration reduced by 50% ~ 85% |
| Operating noise | Gear meshing + motor vibration, ≥95dB | No mechanical meshing, oil-cooled noise reduction | ≤95dB, actual measurement below 82dB |
| service life | Speed reducers require major overhaul every 5 to 8 years, and their bearings need frequent replacement. | Gear-free fatigue, oil-cooled lubricated bearings, maintenance-free operation | Designed service life: 25 to 30 years. A certain aluminum industry project in Yunnan has operated trouble-free for a decade. |
| Maintenance cost | Regular oil changes, gear replacement, shaft alignment, and frequent shutdowns | Requires no routine maintenance, cutting maintenance costs by over 80%. | Greatly reduce operation and maintenance costs |
| Environmental adaptability | Frequency converters are vulnerable to dust, moisture and high temperatures. | Pure mechanical structure, no electronic components, no harmonics | Fully adaptable to high temperature, high humidity, heavy dust, flammable and explosive environments |
Quick Overview of Six Core Highlights:
| Serial Number | Highlights | Explanation |
|---|---|---|
| 1 | MIIT "Domestic Leading" Certification | Registered core technology (Certificate No.: 202034ZK4474), selected into the first batch of National Advanced and Applicable Technologies and the National Catalog of Industrial Energy-Saving Technologies |
| 2 | 2025 "Anhui Premium Industrial Products" | Authoritatively recognized by the Department of Industry and Information Technology of Anhui Province, a benchmark in the field of high-end equipment manufacturing |
| 3 | Precise Speed Regulation of Worm Gear and Worm | It generates greater axial thrust, delivers higher precision and lower latency, and enables accurate and controllable air gap adjustment. |
| 4 | Light-load soft start | The air gap reaches its maximum at startup. The motor starts under no load with an extremely small inrush starting current, which prevents bearing creep. |
| 5 | Tolerance for large centroid errors | Non-contact connection allows for large installation deviations, simplifies installation and commissioning, and shortens the construction period. |
| 6 | Zero harmonic and low power consumption | Pure mechanical speed regulation, no high-order harmonics generated, no self-power consumption, and no motor overheating during low-speed operation. |
A WF-TW670 unit manufactured in 2017 was returned to the factory for disassembly and inspection. After six years of exposure to harsh conditions, while the nameplate on the outer casing showed signs of weathering, the internal permanent magnet disc, bearings, speed regulating mechanism and cabinet remained spotless, with no rust or cracks whatsoever. This is the outstanding performance of the oil-cooled permanent magnet speed regulator.
三、Application Scenarios — Cases Prove Reliability
The Voofu horizontal oil-cooled permanent magnet speed regulator covers a power range from 0 to 5000 kW. It is mainly designed for horizontal vane pumps and fans with power above 630 kW. It has been widely applied in seven major sectors including power, metallurgy, chemical industry, cement, coal, iron and steel, and military industry, with its market share ranking among the top tier of the industry.
Typical Application Cases
| Application Scenarios | Project Cases | Core Data |
|---|---|---|
| Induced draft fan speed regulation | Guodian Zhenjiang Thermal Power Plant Unit 3 | Adopting the WF-TW850 (1400kW) unit saves 2.2458 million kWh of electricity annually, equivalent to a standard coal reduction of 729.88 tons and an annual CO₂ emission cut of 2023.6 tons. The payback period of the investment is only 0.9 years. |
| Slurry circulation pump | A power plant (1400kW/1480rpm) | Energy saving rate: 25% ~ 40%. The non-contact flexible connection eliminates vibration and impact, enabling maintenance-free operation of the system. |
| Heat Network Circulating Pump | A power plant in Northeast China (1600kW/1486rpm) | WF-TW850 has been operating trouble-free for nearly a decade since its commissioning in 2016, with precise speed regulation to meet heating requirements. |
| Circulating Fan | A Circulating Fan Project in Panjiang, Guizhou | Ship 6 units of WF-TW750 in one batch for mass deployment in energy-saving renovation of high-power circulating fans. |
| Air-cooled fan | Renovation of air-cooling islands in multiple thermal power plants | Replaces traditional gearboxes with an energy saving rate of approximately 30% and a payback period of around 2 years |
四、Why choose oil cooling instead of water cooling?
Voofu has phased out its early water-cooled solutions amid technological upgrades, targeting core pain points directly:
| Comparison items | Water-cooled | Voofu Oil-cooled Type |
|---|---|---|
| Sealing method | Oil-water seal dynamic seal | Fully Sealed with Thin Oil |
| Leakage risk | Water leaks into the bearing → Lubrication failure / Oil carbonization; Mutual leakage of water and oil → Grease emulsification | No leakage, oil film protection |
| Bearing life | Short and fragile | Forced lubrication, continuous operation for more than 5 years |
| rust resistance | None | Oil film isolation keeps the cabinet looking brand new for 6 years |
| High-power capability | ≤2000kW (Heat dissipation is only 300kW) | ≤5000kW (Oil cooling heat dissipation efficiency increased by 1.5 times) |
Actual Comparison: A water-cooled permanent magnet speed regulator manufactured in 2015 was disassembled for maintenance, revealing extensive internal rust and cracked discs. By contrast, the Voofu oil-cooled model WF-TW670 produced in 2017 remained immaculate inside after six years of service upon its return to the factory. Facts speak louder than words.
Conclusion
Against the backdrop of China's Dual Carbon goals and the Motor Energy Efficiency Improvement Plan, Voofu horizontal oil-cooled permanent magnet speed regulators follow a minimalist design philosophy that eliminates all intermediate links. Featuring no gears, couplings or frequency converters and generating no harmonics, it transmits torque through an air gap and ensures reliable operation with thin lubricating oil.
It is not an upgrade to conventional products, but a full replacement.
As a national Specialized, Refined, Unique and Innovative Little Giant Enterprise and a National Intellectual Property Advantage Enterprise, Voofu Permanent Magnet holds over 300 patents in total. We power a greener future with permanent magnet technology.
