High-Pressure EC Plug Fan for AHU Integration: 1442 Pa Case Study

What the AHU builder needed

An HVAC maker building a compact air handling unit for Europe sent a short request. They needed the 3D STEP file for our LWBE3G250-102NS-20 EC plug fan.

That is a routine step for any engineering team. Equally, it is a signal. You ask for a CAD model when the design is real and the fan is already chosen.

Meanwhile the performance behind it was 1442 Pa of peak static pressure. Their AHU packs in a dense filter bank and a deep cooling coil. Consequently the airflow path resists heavily.

• Firstly, 230V single phase at 50 or 60Hz.
• An envelope of roughly 280mm across by 150mm tall, since space is tight.
• Lastly, variable speed through a 0-10V signal from their central controller.

That control line is not a preference. European ErP rules, namely Tier 2 of Regulation (EU) No 1253/2014, effectively require it. Meanwhile demand-controlled ventilation depends on it as well.

Confirming the EC plug fan selection

The request was for a file. However, the real question was whether the customer had chosen well. So our team checked their duty point against the fan performance and acoustic data before sending anything.

Why the other fan types are not candidates

An axial fan simply cannot make 1442 Pa. Consequently it is ruled out at once, rather than argued about.

A forward-curved wheel is compact. Near this pressure, though, it runs less efficiently and risks instability. Backward-curved is the only right choice for high pressure at high efficiency.

Why EC rather than AC with a drive

Admittedly an AC motor with a separate VFD was possible. We rejected it for three reasons. The drive loses efficiency, it takes cabinet space, and it complicates the wiring.

An integrated EC plug fan takes the customer 0-10V signal directly through its onboard SmartEC electronics, so none of those costs arise.

The trade-off the customer accepted

Reaching 1442 Pa from a 250mm impeller means 4100 RPM. High pressure from a small wheel always costs speed. Speed, in turn, costs noise.

Here the resulting 93 dB(A) free-field figure is expected rather than surprising. The OEM handles it with acoustic treatment inside their cabinet, which is how this class of fan is always used.

With the choice confirmed, our team pulled the approved STEP file and sent it on. Consequently their engineers began virtual prototyping at once. Checking clashes, planning cable routes, and preparing system-level CFD.

Technical Specifications

The noise figure below is a free-field measurement at full speed and pressure. Inside a cabinet it falls a long way. The questions at the end explain why.

Technical Documentation

Access to accurate technical documentation is essential for system integrators and design engineers. The following documents were central to this project.

This 3D product image provides a quick visual reference for the fan’s geometry and construction, useful for initial design reviews.

LWBE3G250-102NS-20.stp

This 3D CAD STEP file is what the customer originally requested; it’s required by design engineers for integration into their host system’s mechanical assembly to verify fit and clearances.

LWBE-250 Series Datasheet

Meanwhile the product datasheet contains all performance curves, technical specifications, and dimensional drawings needed by an HVAC engineer to select the correct fan for their required duty point.

Why the OEM designed us in

Beyond the fan itself, three things counted.

• A documented, quick process. A 3D model request moved from sales to engineering fulfilment as a standard procedure. That operational habit is the same one underpinning our 90-day NPI cycle, against the 12 to 18 months imported European brands typically quote.
• Equivalent engineering, better economics. This EC plug fan performs on a par with premium German brands, yet the price point is materially lower, which reduces bill-of-materials cost without touching performance or the energy rating.
• Capacity behind the support. Sending one 3D file is easy. Supplying over 30,000 cold chain units and 120,000 data center units a year is not. In short, that is what tells a partner our engineering support rests on real production.

Browse our EC plug fan range, or the AHU fan section. Ecodesign requirements come from the European Commission.

Questions during integration

What are the lead time and MOQ?

Mass production for a standard EC plug fan runs 15 to 30 days. MOQ varies with size, generally between 100 and 500 units. For a first-time partner we can often accept smaller initial orders, down to 50 units, to support internal validation and launch.

Can the SmartEC firmware be tailored to our start-up sequence?

Yes. Firmware work is normal engineering support for OEM partners. We regularly modify the speed curve, the start and stop ramp times, and Modbus communication registers. That work fits inside our 90-day NPI cycle.

The 93 dB(A) figure worries us. How do other customers handle it?

That number is a raw free-field measurement at full speed and pressure, taken to ISO 5801. In a real AHU, however, the fan sits inside a cabinet, so system noise is far lower. OEMs manage it with acoustic insulation, intake and discharge silencers, and by keeping resonances out of the enclosure. We supply 1/3 octave band sound power data so your engineers can model it properly.

Why does a plug fan suit high pressure inside an AHU?

Because the scroll housing a normal centrifugal fan needs is redundant in a plenum, and it costs both space and pressure. Removing it shortens the assembly and lets the plenum do the work. Consequently 1442 Pa becomes achievable in a 280mm envelope.