DWDI backward-curved EC motor fans — maximum efficiency for air handling units

DWDI fans with backward-curved blades and EC motor are the highest energy-efficiency configuration in the entire centrifugal incorporable fan family — combining three simultaneous advantages: DWDI double-inlet for high airflow, backward-curved blades for high aerodynamic efficiency and self-limiting characteristic, and EC motor for 90–95% electrical efficiency.

Why backward-curved blades are superior for efficiency: backward-curved geometry produces a self-limiting power-airflow characteristic — the required power decreases when airflow increases beyond the nominal point, preventing motor overload in any operating condition. It is the only centrifugal blade configuration safe for operation without external airflow limiting. Combined with the EC motor continuously adjusting speed, the result is a system that cannot overload the motor and operates permanently at maximum efficiency across the entire airflow range.

Total system efficiency (TTE) — EC motor + backward-curved DWDI rotor — reaches 60–75% at the optimal point, compared to 40–55% for AC configurations with forward-curved blades. This difference accumulates into hundreds of thousands of kWh over the service life of a commercial AHU running 8,000 hours per year.

The EC driver is mounted directly on the casing (plug-and-play), accepts 0-10V or Modbus RS485 signal, has integrated thermal protection and automatic derating at elevated temperatures — no external intervention required. IP54 protection class for the entire drive system.

Typical applications: high-performance AHUs for hospitals, clean rooms, laboratories and any installation where energy efficiency is a mandatory design criterion; VAV systems where the motor continuously operates at partial loads (the regime most favourable for backward-curved + EC); ventilation units for nZEB buildings where the own consumption of the ventilation system is normatively limited; and any energy-certified AHU where fan efficiency is audited.

DWDI forward vs. backward — how to choose: if maximum airflow and compact footprint take priority over peak efficiency → forward-curved. If energy efficiency, overload safety and energy certification take priority → backward-curved. For nZEB installations and continuous-operation systems, backward-curved + EC is the standard selection.

👉 DWDI forward curved EC motor — higher airflow, compact footprint 👉 Plug backward curved EC motor — single inlet, plenum design