AC Cross-Flow Fan for HVAC OEM: Custom Motor Mount Case Study

What the OEM ran into

A European HVAC OEM designing low-profile fan coil units had already picked our LWCA-60180SN-06 AC cross-flow fan on performance. It gives 170 m3/h inside a 254mm mounting length.

Then prototyping found a problem with nothing to do with airflow. The standard motor position puts the cable exit exactly where their chassis sits. Consequently the two would not fit together.

Changing the chassis was out. Tooling was already committed, and the launch date was fixed.

So the request was simple: modify the fan instead.

• 230V AC at 50Hz.
• A total length of 254mm and a 60mm impeller, both fixed by the standard drawing.
• 170 m3/h at 58 Pa, plus noise no higher than 46 dB(A).
• An operating range of -10C to +60C, at both ends.
• Existing CE and ETL certification kept intact, since recertifying would wreck the timeline.

That last point deserves emphasis. A change that voids a certificate is never a cheap change, whatever the engineering costs.

Rotating the motor on the AC cross-flow fan

The customer had chosen well on performance, so nothing aerodynamic needed touching. Basically the whole job was physical fit.

Alternatives we rejected

A different motor was the first thought, and it went nowhere. The shaded pole motor specified is the cheapest sound choice for a fixed-speed duty. Swapping it would only inflate the bill of materials.

Proposing a DC or EC model was the second idea, and it was worse. Variable speed sounds like an upgrade. However, the customer would then have to add a 0-10V or PWM signal they have no use for, and pay more for it.

The change that actually happened

We created a variant, LWCA-60180SN-06-16, to identify this specific build.

Behind that number sits one change to the assembly work instruction for the LWCA-60 series. Operators turn the motor to the position shown in the customer photograph, then fix it to the galvanized steel housing. Afterwards the cable exits where their chassis expects it.

Our documentation team then drew a revised spec sheet for the -16 variant. It passed review and went back to the customer before anyone raised the sample order.

That is the entire engineering content of this project. Even so, it needed a part number, a drawing and a controlled work instruction. The next section explains why.

Technical Specifications

Every figure below is unchanged from the standard AC cross-flow fan. That is rather the point here, since the change is purely mechanical.

Technical Documentation

Drawing & Specification Sheet (PDF): This final approved specification document, `LWCA-60180SN-06-16.pdf`, is used by the customer’s design engineers for CAD integration and by their quality teams for incoming parts inspection. Download the full PDF here.

Customer Requirement Image: This image, provided by the OEM’s engineer, clearly shows the required motor rotation and wire exit position needed to resolve the mechanical clash in their assembly.

Why a tiny change was worth formalising

In the end, four things made a very small change worth doing formally.

• Days rather than months. imported European brands often quote months for a minor mechanical change. This went from request to approved drawing and a production-ready sample within days.
• A version-controlled part number. An email request became a formal variant with its own number. Consequently the customer gets the identical part on every future order, rather than trusting somebody to remember.
• No forced upgrade. Modifying an existing high-volume AC cross-flow fan met the fitment need without pushing the customer onto a more expensive EC platform they did not need.
• Certification untouched. Because the change is purely mechanical, and alters no motor, wiring or safety-critical component, the existing CE and ETL certifications remain valid. That saved the customer both the time and the substantial cost of third-party retesting.

Browse our cross-flow fan range, or the AC cross-flow fan series for other lengths. Safety standards are published by UL Solutions in UL 507.

Questions about custom orientations

What is the lead time for a custom motor orientation?

For an existing AC cross-flow fan, a sample with a rotated motor is usually ready within 7 to 10 working days after the drawing is confirmed. A first mass production order then runs roughly 15 to 25 days, which is our standard make-to-order window for HVAC products.

Does rotating the motor change performance or certification?

No. It changes where the motor housing sits relative to the fan, not the aerodynamics or the electrical properties. Airflow stays at 170 m3/h, pressure at 58 Pa and noise at 46 dB(A). Compliance with CE, RoHS and ETL to UL 507 is unaffected.

What L10 life applies at the maximum temperature?

Here the published 40,000 hours is referenced at 25C. Running continuously at the 60C maximum derates it, and by how much depends on your duty cycle. For a critical application, send us the operating parameters and our engineers will calculate it properly rather than quoting a rule of thumb.

Why formalise something this small with a new part number?

Because an informal instruction lasts exactly as long as the person who remembers it. A version-controlled variant means the tenth batch is built like the first. In short, that is the difference between a change and a recurring production problem.