LWAC-BG4515S Industrial Air Curtain for 380V High Power Doors

Customer Requirement

One of the customers approached use for two specific industrial air curtain models. This customer is a system integrator who requires a model operating at up to 2600W on a 380V, 50Hz supply. The request was for a price quote on a one-time purchase of nine units of the LWAC-BG4510S-01 and nine units of the LWAC-BG4515S-01. The core numbers: 4150 m³/h for the shorter unit, 7520 m³/h for the longer one, both pushing air at 25 m/s. That’s fast. Fast enough to hold a clean separation across a wide opening — temperature, dust, bugs, whatever the warehouse throws at it. The customer is on a 380V/50Hz supply, with each unit hitting up to 2600W. Straightforward, spec-driven selection.

The customer’s procurement team came in with a simple request: price and quantity. That was it. But when things moved to the sales confirmation stage, the conversation shifted. They wanted a magnetic door switch wired in, so the curtains fire up automatically when the door opens.

Engineering Solution

Longwell’s engineering team checked LWAC-BG4510S-01 and LWAC-BG4515S-01 centrifugal air curtains for the required performance goals. The initial quote was based on these standard AC motor-driven models. The project took a technical turn when the customer requested the addition of a magnetic door switch for automated on/off control.

The core engineering problem became clear. The AC motors in these units draw significant power (1400W and 2600W). A simple magnetic reed switch, which the customer likely envisioned, cannot handle the high current and massive inductive load of such a motor. Directly connecting the switch would cause a hazardous arc flash and immediate switch failure upon the first operation. The team evaluated two paths forward.

The first and only safe solution for this AC model involved an external control box. This approach uses the low-voltage magnetic door switch to operate the coil of a properly rated 3-phase motor contactor (a heavy-duty relay). The contactor would safely handle the high-power switching for the air curtain’s motor. While this is the standard and correct electrical engineering solution, it adds cost, components, and installation complexity that were not part of the original customer budget. The project was ultimately unsuccessful because the customer required a simpler, integrated solution that the standard AC product’s architecture could not provide at the target price point.

This challenge highlighted a key design consideration. A different approach using a Longwell air curtain equipped with a SmartEC™ motor would have solved the problem elegantly. The integrated electronics of an EC motor can accept a low-voltage signal from a door switch directly to its control input, managing the high-power motor internally without any need for external contactors.

Technical Specifications

The high exit velocity of 25 m/s is essential for establishing an effective air barrier over the full height of a tall industrial doorway. The specified air volumes of 4150 and 7520 m³/h ensure sufficient air mass is moved to maintain environmental separation under typical pressure conditions.

Technical Documentation

This product data sheet provides HVAC engineers and procurement managers with the primary specifications, including dimensions, electrical requirements, and aerodynamic performance, for the entire LWAC industrial air curtain series.

Why Longwell for This Application

• Engineering Integrity & Transparency: LONGWELL is committed to finding a safe and best solution to protect the end user. When the customer floated a quick-and-dirty approach, our engineering team pushed back — not to be difficult, but because you don’t gamble with line-voltage gear on a warehouse floor. We explain the technical challenge of switching a high-power inductive load and proposing the correct, albeit more complex, contactor-based solution.
• Cost-Effective Standard Portfolio: The customer’s initial inquiry was driven by a need for powerful, reliable, and budget-conscious hardware. As a Ningbo-based manufacturer with 35 years of experience, Longwell’s standard catalog products offer a 35-38% lower price point than European equivalents, making us the default starting point for value-conscious OEM procurement.
• A Pathway to Advanced Solutions: This project’s limitation with AC motors perfectly illustrates the strength of our advanced technology portfolio. The entire control challenge would be eliminated by using a model equipped with a Longwell SmartEC™ motor, which allows for simple, direct, low-voltage control. This positions Longwell as a partner who can solve not just today’s request but tomorrow’s integration challenges.
• Verified Performance Data: The customer could confidently specify units based on our catalog data (e.g., 7520 m³/h from the 1500 mm model). Our performance testing is verified against AMCA 210-16 and ISO 5801 standards, giving engineers and system integrators trustworthy data without requiring their own expensive and time-consuming validation.

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Frequently Asked Questions

Q: What is the correct way to control a high-power air curtain like the LWAC-BG4515S-01 with a door switch?

A: A high-power (2600W) AC motor cannot be switched directly by a standard magnetic door switch. The correct method is to use the door switch as a low-voltage signal to activate a 3-phase motor contactor rated for the motor’s full load amperage and inductive characteristics. The contactor handles the high-power switching, preventing arc damage and ensuring safe, reliable operation. Longwell can provide guidance on selecting an appropriate external contactor.

Q: Are there air curtain models that allow for simpler door switch integration?

A: Yes. While these standard AC models require an external contactor, Longwell air curtains built with our SmartEC™ motors can be controlled directly. The EC motor’s integrated electronics accept low-voltage signals (like a 0-10V signal or a simple dry contact from a door switch) to start, stop, or modulate speed. This eliminates the need for high-power external relays and significantly simplifies installation.

Q: What is the maximum effective mounting height for an air curtain with 25 m/s exit velocity?

A: An exit velocity of 25 m/s, as provided by the LWAC-BG4510S-01 and LWAC-BG4515S-01, is generally suitable for industrial and commercial doorways up to 4.5 to 5.5 meters high. The effectiveness of the air barrier also depends on site conditions such as cross-drafts or building pressure imbalances. For critical applications, a site-specific analysis is recommended to confirm performance.

Project Gallery & Technical Drawings

Project Item: 6987333989-LWAC-BG4510S-01&LWAC-BG4515S-01
Project Date: 2026-05-11 03:53:01