610mm Cross-Flow Fan Housing & Impeller for HVAC OEMs

Customer Requirement

A 610 mm long cross-flow fan sub-assembly was the core of a request from an existing HVAC OEM partner. The customer required only the impeller and housing assembly based on Longwell’s established LWAC-50610 series.

The application was for a line of high-volume commercial HVAC units, likely fan convectors or trench heaters, which require a long, linear, and uniform airflow pattern. The hard mechanical constraints were dictated by the OEM’s final product chassis. The assembly needed a total length of 610 mm, accommodating a 610 mm aluminum impeller with a 50 mm diameter. The customer’s engineering team needed to integrate their motor with the specified ø3.2 mm steel shaft. The primary goal was to secure a reliable source for the aerodynamic components, confirm a minimum order quantity (MOQ), and get pricing for mass production samples under the new part number LW-50610-01.

Engineering Solution

Upon receiving the request, the project was assigned to a technical PM and classified as a ‘Light Development-Quotation’ project. This internal process bypasses the full 90-day NPI cycle for simple modifications of existing products. The engineering team’s task was to validate the request, generate the necessary documentation for a motorless assembly, and provide data for costing.

The key engineering decision was to isolate the bill of materials for the housing and impeller from the parent assembly, LWAC-50610SN-07. This involved confirming that the iron side plates, aluminum housing profiles, and aluminum impeller could be kitted directly from the high-volume production line without any new tooling. This validation was critical to providing a competitive price point. The most important deliverable was the final technical drawing for LW-50610-01 to give OEM’s engineers a clear integration target. By creating the distinct part number, Longwell ensured traceability and error-free ordering for future mass production batches. The final solution enabled the OEM to leverage Longwell’s manufacturing scale for the air-side components while retaining complete freedom on their motor and control strategy.

Technical Specifications

The following specifications are for the reference model LWAC-50610SN-07, which uses the same aerodynamic components as the LW-50610-01 sub-assembly. The performance data illustrates the design-intent duty point when paired with a standard 26W AC shaded pole motor.

These specifications for the complete unit provide a performance baseline. The LW-50610-01 sub-assembly provides the aerodynamic foundation for OEMs to match or exceed this performance with their own custom-selected motor and drive system.

Technical Documentation

Final documentation for the project confirms all mechanical details and provides the reference performance context for system integration.The approved technical drawing for LW-50610-01 details all critical dimensions, materials, and assembly notes for procurement managers and integration engineers.

Download Reference Model LWCA-50 Series Datasheet
This reference specification sheet for the complete LWAC-50 series fan provides the baseline performance data an HVAC engineer would use to design their motor and drive system.

Why Longwell for This Application

OEMs choose Longwell for component-level partnerships for several specific reasons beyond just the finished product. This project highlights a few key advantages:

• Component-Level Supply Chain Access: Longwell’s vertically integrated manufacturing allows OEMs to procure critical sub-assemblies like the LW-50610-01. This unbundling provides direct access to cost-effective, high-volume aerodynamic components, offering a typical cost advantage of 35-38% compared to sourcing similar mechanical parts from European competitors.
• Streamlined Documentation for Modified Parts: The request was handled through a ‘Light Development’ workflow. This internal process enabled the engineering team to generate final drawings, confirm specifications, and provide a quote without the cost or 12-18 month delay of a full NPI cycle, moving efficiently from input to confirmation.
• Pre-Validated Engineering: The OEM based their request on an existing Longwell design. This foundation of trust is built on Longwell’s 35-year history and adherence to performance testing standards like AMCA 210-16. The OEM could design their system with confidence in the fan’s aerodynamic performance.
• Enabling OEM Innovation: This partnership model supports OEM innovation. By supplying the core air-moving ‘chassis,’ Longwell empowers the customer to develop their own value-add on the drive side—be it with a high-efficiency SmartEC™ motor, a specific voltage for global markets, or deep integration with a proprietary building management system.

Explore our full Cross-Flow Fans range.

Frequently Asked Questions

Q: Can I order this LW-50610 cross-flow fan with a motor other than the standard 230V AC, for example, a 24V DC EC motor?

A: Yes. While this specific project was for a motorless assembly, a common request is for custom motor integration. Longwell’s 90-day New Product Introduction (NPI) process is built for this. We can integrate a customer-specified motor or develop a SmartEC™ version with 0-10V/PWM/RS485 controls. The typical lead time to receive 3-5 engineering samples of a custom 24V DC version is 45-70 days.

Q: What is the typical MOQ and lead time for a semi-custom assembly like the LW-50610-01 housing and impeller?

A: For a modified standard part, the minimum order quantity for mass production is determined during the quotation stage and is generally between 100 and 500 units. The standard Make-to-Order (MTO) lead time for such HVAC components is 15-30 days after the purchase order is confirmed. This rapid turnaround is a key advantage of our Ningbo-based manufacturing.

Q: The drawing specifies different materials for the impeller and side plates. What is the reason for this?

A: The LW-50610-01 drawing specifies aluminum (Al) for the impeller and the main housing scrolls. This material is chosen for its light weight, which reduces the required motor torque and rotational inertia for faster spin-up. The left and right side plates are made of iron, which provides superior structural rigidity and creates a durable mounting point for securing the entire 630 mm assembly inside the customer’s final product.

Project Gallery & Technical Drawings

Project Item: 6991496856-50610
Project Date: 2026-05-14 09:28:29