EC Axial Fans for Dehumidifiers: 4,944 m³/h Case Study

What the enquiry contained

2,500 m³/h and 5,000 m³/h airflow targets were specified by a European industrial dehumidifier manufacturer looking to replace their legacy AX3000 fan units. The previous AX3000 model delivered 3,000 m³/h while drawing 100W at 230V/50Hz, weighing 13 kg with dimensions of 620 x 450 x 295 mm. The application requires deploying standalone axial fans alongside adsorption dehumidifiers to accelerate the drying process for floors, walls, and ceilings in commercial spaces. By increasing the air velocity across wet surfaces while the dehumidifier processes the ambient moisture, the overall drying cycle shortens significantly.

The procurement specifications outlined two distinct volume tiers. Model A needed to deliver 2,500 m³/h for a projected annual volume of 2,000 to 3,000 units. Model B required 5,000 m³/h for a demand of 1,000 to 1,500 units per year. Both units had to operate continuously on a standard single-phase 230V ±10% 50 Hz power supply.

Given the European deployment environment, the OEM required strict compliance with the ErP Directive (EU) 327/2011, CE marking, and the Machinery Directive 2006/42/EC. A minimum ingress protection rating of IP54 was mandatory, with IP55 preferred, to withstand damp construction site conditions. The environmental operating threshold was set at 0 °C to +40 °C. Mechanically, the fans operate in a free-blowing configuration. The customer specifically requested EC motor technology with stepless 0-10V or PWM speed control to allow operators to adjust the air velocity based on the room size and drying phase.

Getting to a workable answer: choosing the ec axial fans

Designing a replacement for the AX3000 required separating the core fan mechanism from the external housing. The Longwell engineering team reviewed the free-blowing installation requirement. We determined that supplying the internal EC axial fans independently would allow the customer to procure their own cylindrical housings and brackets locally. This approach drastically cuts their overall shipping footprint and unit cost.

An initial evaluation of AC shaded-pole and capacitor-run motors was immediately discarded. Standard AC motors could not meet the stringent ErP (EU) 327/2011 efficiency requirements necessary for continuous industrial operation in Europe. They also lacked the native 0-10V stepless speed control the customer required. Instead, we selected Longwell’s SmartEC™ technology. This configuration integrates the motor and controller directly, allowing input of a 1K–10KHz PWM signal or a 0-10VDC control voltage without external drives.

For the 2,500 m³/h requirement (Model A), we selected the LWAE3G315ST-5PEW-04-00. This 315mm axial fan features a PA66 plastic impeller to minimize weight while delivering 2,575 m³/h (1,515 CFM) at a maximum speed of 2,100 RPM. It draws just 1.1A and 165W at full load.

For the heavier 5,000 m³/h requirement (Model B), we engineered the LWAE3G400SS-5MEW-03-00. This 400mm fan requires higher structural rigidity to push larger air masses continuously. We opted for a sheet steel impeller rather than PA66. It achieves 4,944 m³/h (2,908 CFM) at 1,600 RPM, consuming 315W and 1.4A. Both EC motors feature Class B insulation and operate comfortably from -25 °C up to +60 °C, easily handling the customer’s 0 °C to +40 °C baseline requirement. Deep groove ball bearings were implemented to guarantee a 40,000-hour L10 life expectancy. This bearing choice is essential for machines left running unattended on remote sites.

The delivered fan

Here the 315W input power on the 400mm model keeps the unit highly efficient for its 4,944 m³/h output, easily surpassing EU ErP requirements. Integrated IP54 protection blocks dust and splashing water, guaranteeing survival in active construction zones.

Every figure above comes from our own test chamber, measured using AMCA 210/211 and ISO 5801 methods. The published procedures behind those numbers are available from AMCA. As always, confirm the duty point against the finished unit before release, since installation conditions move it.

Drawings, curves and datasheets

The following engineering documents govern the performance and compliance of the supplied axial fans.

longwell–spec-sheet-01.pdf – The primary specification sheet for the 315mm fan, providing the P-Q performance curve and dimensional drawings for engineers designing the local fan housing.

longwell–technical-doc-02.pdf – The datasheet for the 400mm fan, detailing the steel impeller layout, 0-10V wiring diagram, and acoustic noise ratings for procurement verification.

A diagram illustrating the required airflow dynamics, showing the axial fan pushing high-velocity air away from the desiccant unit to dry floor panels.

Meanwhile the legacy AX3000 technical specifications provided by the customer to establish the baseline replacement metrics.

Commercial tier data for the 400mm unit demonstrating the price scaling at 1,000+ unit volumes.

Cost breakdown for the 315mm variant, displaying OEM purchasing targets.

Why this project suited Longwell

• Separated Component Supply Model: Rather than forcing the OEM to buy fully assembled heavy drum fans, Longwell supplied only the calibrated 315mm and 400mm EC fan-motor assemblies. This decision cuts transcontinental shipping volumes drastically, allowing the European buyer to source bulky steel cylinders and brackets locally to save on freight costs.
• CE and ErP Certification Speed: Because the final dehumidification equipment will be deployed across Europe, ErP Directive (EU) 327/2011 compliance is mandatory. Longwell’s established TÜV NORD Notified Body partnership in Ningbo ensured all CE and efficiency documentations were ready immediately, bypassing the usual 12-to-18-month European compliance queue.
• Substantial Cost Reductions: imported European brands typically command high premiums for EC motors of this scale. By engineering an equivalent SmartEC™ solution locally in Ningbo, Longwell achieved a materially lower price point without sacrificing the required 40,000-hour L10 bearing life.
• Precision Stepless Integration: The inclusion of SmartEC™ technology means the fans accept a direct 0-10VDC or PWM (1K–10KHz) signal. The OEM avoided purchasing secondary motor controllers or VFDs, wiring the fan directly into their existing desiccant machine’s main PCB.
• Extreme Temperature Tolerance: While the customer requested a minimum ambient range of 0 °C to +40 °C, the supplied EC motors operate safely from -25 °C up to +60 °C. This thermal overhead prevents motor degradation if the fans are placed too close to the exhaust of a hot desiccant rotor.

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Common questions on this build

Q: Can these axial fans be operated with a standard wall potentiometer?

A: Yes. The included SmartEC control circuit accepts a 0-10V input. By connecting a 10K ohm potentiometer to the 10VDC auxiliary output, operators can manually dial the fan speed from 0 up to the maximum 2,100 RPM on the 315mm model.

Q: What happens if a worker blocks the fan grille on a construction site?

A: The Longwell EC motors feature integrated locked-rotor protection and over-current protection. If debris stops the PA66 or steel impeller, the system cuts power internally to prevent the 315W or 165W motor windings from burning out, automatically attempting to restart after a delay.

Q: Why use PA66 plastic for the 315mm fan but sheet steel for the 400mm fan?

A: The 315mm model pushes 2,575 m³/h, where PA66 provides sufficient structural strength while reducing total weight and rotational inertia. At 4,944 m³/h, the 400mm model experiences significantly higher aerodynamic stress, requiring the rigidity of a welded sheet steel impeller to maintain the G6.3 balancing standard.