Month: May 2026

Cross-flow impeller and motor matched by sample teardown
By longwell / May 14, 2026 / Engineering Case Studies

They Sent a Physical Sample. We Measured It Rather Than Read It.

A drawing tells you what someone intended. A sample tells you what was...

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Cross-flow fan guard current margin shown against the standard model
By longwell / May 14, 2026 / Engineering Case Studies

Why the Custom Version Draws More Current Than the Standard One

Two datasheets for the same fan show different current. That is not an...

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A 53mm BLDC motor component with 0-10V control and FG output
By longwell / May 14, 2026 / Engineering Case Studies

Buying the Motor Instead of the Fan

Some OEMs design their own air path and want the motor only. That chan...

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Fixed setpoint pressure switch for a gas furnace airflow interlock
By longwell / May 14, 2026 / Engineering Case Studies

Why a Safety Switch Should Not Be Field-Adjustable

An adjustable switch is convenient for the installer. On a gas furnace...

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Forward-curved fan, 250mm, in a shallow air handling unit cabinet
By longwell / May 14, 2026 / Engineering Case Studies

Forward-Curved at 407 Pa: When the Rule of Thumb Loses

The usual rule says backward-curved above 200 Pa. Here the cabinet dep...

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A 406mm axial impeller with a D-bore made by a custom mold insert
By longwell / May 13, 2026 / Engineering Case Studies

A New Bore Does Not Need a New Mold, Only an Insert

The blade mold already existed. Only the center had to change, and tha...

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ec fans in hvac ventilation
By longwell / May 13, 2026 / Technical Articles

EC Fans in HVAC Ventilation: Driving the Future of Energy-Efficient Airflow

In today’s fast developing pace, efficiency is paramount in every indu...

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White powder coated weather cowl for an exterior duct termination
By longwell / May 13, 2026 / Engineering Case Studies

Why Paint Was the Wrong Answer for an Outdoor Cowl

The requirement was purely cosmetic. The engineering was entirely abou...

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EC fan replacing a unit limited by shaded-pole motor speed control
By longwell / May 13, 2026 / Engineering Case Studies

You Cannot Put a VFD on a Shaded-Pole Motor

The obvious way to add speed control to an existing AC fan does not wo...

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Universal voltage fan, 172mm EC axial, rated IP55
By longwell / May 12, 2026 / Engineering Case Studies

One Fan SKU for Every Market: The 100-240V Argument

They asked for an EC replacement. What they got that they had not aske...

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