AC Axial Fans for Condenser Units: 6695 m3/h Case Study

What the OEM actually asked for

The request came from a procurement team rather than an engineering one, and it was refreshingly precise. They wanted the full technical package for two AC axial fan models: the LWAA6E550S-5MEB-05 and the smaller LWAA4E350S-5MEB-09.

They named two deliverables. Firstly final-version PDF datasheets, then 3D STEP models for CAD.

That pairing tells you exactly where the project had reached. Engineering wants to check fit and clearance in the model. Meanwhile procurement wants specifications for the bill of materials and the compliance file. Both requests usually arrive together in the last weeks before a design freezes.

• A 550mm impeller on the larger AC axial fan, and 350mm on the smaller one.
• 220 to 230V at 50 Hz, the standard European supply.
• External rotor AC motors on both, with IP54 and IP55 protection.
• An operating range from -30C to +60C.
• Compliance with EN 60335 for appliance safety.

Nobody stated the end application. Even so, that combination points squarely at outdoor equipment: air-cooled condensers, commercial refrigeration, or large ventilation plant where the weather is part of the specification.

Confirming the AC axial fan selection

This was a standard part enquiry rather than a development project. The customer had already chosen the models. Our job, therefore, was to confirm they suit the application and return accurate documents quickly.

Confirming the two selections

Here the LWAA6E550S-5MEB-05 is a 550mm fan delivering 6695 m3/h. Similarly, the LWAA4E350S-5MEB-09 is a 350mm unit at 3348 m3/h. Both are long-running workhorses in our range rather than anything exotic.

Why we did not push EC

An EC fan would give better efficiency and integrated control through our SmartEC platform, with 0-10V, PWM or Modbus. We considered it internally and left it alone.

The reason is that choosing an AC axial fan is usually a signal in itself. It generally means one of three things: the project is cost-driven, the fan is replacing existing AC infrastructure, or the designer simply wants the simplicity of mains power with no electronics in the loop. In all three cases an EC proposal is unwelcome.

What is inside both fans

Both fans use cold-rolled steel impellers on housed external rotor motors. That construction keeps the assembly compact and stiff.

• Class F insulation, with an S1 continuous duty rating.
• Integrated thermal protectors that cut power between 150 and 160C.
• Maintenance-free deep groove ball bearings, so mounting orientation does not matter.

That thermal protector is worth noting. A blocked condenser coil raises motor temperature long before anyone notices the airflow has dropped. Consequently the protector is what stops that becoming a burnt-out winding.

Finally we pulled the approved datasheets and 3D models from the archive and sent them on. It took very little time, which was rather the point.

Technical Specifications

Two models sit side by side below. Compare the protection ratings carefully, since they differ between the 550mm and the 350mm unit.

Technical Documentation

Meanwhile the following documentation was provided to the customer to support their design, procurement, and integration processes. All performance data is based on testing according to ISO 5801 and AMCA 210/211 standards.

LWAA6E550S-5MEB-05 Datasheet (PDF): This document provides complete electrical and aerodynamic data, P-Q curves, and mechanical drawings for the 550mm fan, required by both engineers and procurement managers.

LWAA4E350S-5MEB-09 Datasheet (PDF): This file contains all technical specifications for the 350mm fan, essential for system validation and component sourcing.

LWAA6E550S-5MEB-05 Source Specification (DOCX): This source document is used by procurement teams to import detailed specifications into their internal management systems.

LWAA4E350S-5MEB-09 Source Specification (DOCX): The source file for the 350mm fan, allowing for easy data integration into customer documentation.

Why the OEM sourced here

For an OEM specifying standard components, the supplier decision runs past the part itself. In this case, four things counted.

• Documents by return. The customer had final approved engineering files immediately. Design teams stall waiting for data, so speed on a standard AC axial fan enquiry is worth as much as it is on custom work.
• Cost that matches the intent. Choosing AC pointed to a cost-sensitive project. What we did not do was reach the price by dropping Class F insulation, thermal protection or the IP54/55 sealing, since those are the parts that decide whether the fan survives.
• Data validated, not asserted. Every datasheet carries a P-Q curve we measure in our own lab to AMCA 210/211 and ISO 5801 methods. Engineers can therefore model system impedance against it with confidence.
• Predictable supply. We have manufactured in Ningbo since 1990, which gives OEMs the stable lead times an assembly line schedule depends on.

Browse our AC axial fan range, or the EC axial fan series where speed control is required. Appliance safety is covered by IEC 60335-1.

Questions integrators ask

What L10 bearing life do these models have?

Both are documented at 30,000 hours. However, the reference ambient differs. It is 20C for the LWAA6E550S-5MEB-05 and 40C for the LWAA4E350S-5MEB-09. Running continuously at the +60C maximum will shorten that. Both use maintenance-free deep groove ball bearings.

Can I use a speed controller?

Yes. As single-phase induction motor fans, they accept an AC voltage controller or a VFD with single-phase 230V output. Be aware that voltage control can raise motor noise and heat at low speed. Where regulation needs to be precise and efficient, a SmartEC fan with 0-10V or PWM control is the better answer.

Can they be mounted horizontally?

Yes, either orientation is approved. Ball bearings rather than sleeve bearings are the reason, because sleeve types are sensitive to shaft attitude. Overall depth is 180.2mm on the 550mm model, and 133mm on the 350mm model.

What separates IP54 from IP55 here?

The 550mm fan is IP54, protecting against dust and splashing water from any direction. The 350mm fan is IP55, which adds resistance to low-pressure water jets. Specify IP55 where the equipment sees driving rain or gets hosed down during cleaning.