Day: September 10, 2026

Curve showing where centrifugal fans surge, left of the pressure peak
By longwell / September 10, 2026 / Fan Engineering Guides

Why Do Centrifugal Fans Surge? (Stall Explained)

Surge is what happens when a fan is pushed too far left on its curve. ...

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Checking whether a fan is spinning in the wrong direction against the housing arrow
By longwell / September 10, 2026 / Fan Engineering Guides

Fan Spinning Wrong Direction? How to Check

A reversed fan still turns, still sounds normal and still draws power,...

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Thermal camera image of an overheating fan motor under load
By longwell / September 10, 2026 / Fan Engineering Guides

Overheating Fan Motor: Causes & Fixes

Heat is what kills motors, and almost every overheating case traces ba...

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Testing the signal on an EC fan not responding to its controller
By longwell / September 10, 2026 / Fan Engineering Guides

Why Is My EC Fan Not Responding to Control Signal?

A fan that runs at one speed regardless of the signal usually has a wi...

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Blower wheel with uneven dirt build-up causing imbalance
By longwell / September 10, 2026 / Fan Engineering Guides

Blower Wheel Out of Balance: Symptoms & Fix

An unbalanced wheel announces itself through vibration at exactly one ...

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Engineer listening to identify whistling and humming fan noise
By longwell / September 10, 2026 / Fan Engineering Guides

Whistling / Humming Fan Noise: Diagnose the Sound

Different fan noises come from different physics. A whistle is usually...

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Axial fan blade pitch and angle of attack shown on a hub
By longwell / September 10, 2026 / Fan Engineering Guides

Fan Blade Pitch & Angle of Attack Explained

Pitch is the single strongest lever on axial fan performance. Increase...

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Airfoil impellers with aerofoil section blades in a centrifugal fan
By longwell / September 10, 2026 / Fan Engineering Guides

Why Airfoil Impellers Are the Most Efficient

Airfoil blades reach the highest static efficiency of any centrifugal ...

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Volute cutoff clearance shown between the scroll tongue and the wheel
By longwell / September 10, 2026 / Fan Engineering Guides

Volute / Scroll Housing & Cutoff Design

The scroll does half the work in a centrifugal fan, and the cut-off de...

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Fan inlet cone and venturi ring guiding air into an impeller
By longwell / September 10, 2026 / Fan Engineering Guides

Inlet Cone & Venturi: Small Part, Big Efficiency

The inlet cone is a cheap pressing that decides how cleanly air enters...

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