Forward Curved Centrifugal Fans
Forward curved (multi-vane) impellers move more air at the same outer diameter in a compact envelope, ideal for space-constrained equipment integration; available single inlet with housing, dual inlet and free-running. Final selection is confirmed at the duty point (airflow / static pressure / voltage / control mode) and by project verification.
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Forward Curved Centrifugal Fans — selection guide
Forward Curved Centrifugal Fans: 46 models, impellers Ø108–500 mm, maximum airflow 155–9,064 m³/h, static pressure to 1,030 Pa, AC and EC motors, across 38 series. 15 of them carry a measured P-Q curve and 46 a dimensional drawing.
Forward curved centrifugal fans are the free-running and housed multi-vane impellers used where space is tight: Ø108 to Ø500 mm, LWFA2E / LWFA4E AC and LWFE3G EC in the compact Ø108–200 mm sizes, and LWFA4D / 6D / 8D three-phase units with rotor 138 / 188 in the Ø225–500 mm sizes for packaged units and ovens. Airflow 155 to 9,064 m³/h at up to 1,030 Pa.
Compared with a backward curved impeller of the same diameter a forward curved impeller moves 30–50% more air at low pressure in a smaller housing, which is why it survives in fan coil units, compact AHUs and process equipment despite lower efficiency.
How to select from this range
- Choose forward curved when the envelope is fixed and the pressure is below about 300–500 Pa.
- The power curve rises with airflow: size the motor for the lowest resistance the system can see.
- Large sizes (Ø225–500 mm) are three-phase 380 V; compact sizes 230 V.
Where these fans are used
- Compact air conditioners and fan coil units
- Ovens, dryers and process heaters
- Packaged ventilation units
Every figure above is measured on our own test rigs per AMCA 210 / ISO 5801 methods — see the test labs and certificates. Final selection is confirmed at the duty point and by project validation.
FAQ — Forward Curved Centrifugal Fans
When is a forward curved fan the better choice?
When the housing depth is fixed and the pressure is low: at Ø200 mm a forward curved fan moves more air than a Ø250 mm backward curved fan at 200 Pa. Above about 500 Pa the backward curved fan wins on efficiency and stability.
Which forward curved sizes are three-phase?
Ø225 to Ø500 mm (LWFA4D / 6D / 8D, 16 models on 380 V); the Ø108–200 mm sizes are 230 V single-phase.