Matched pressure and efficiency required
Fan Shaft Power Estimate
Estimate air power and fan shaft power at one documented operating point. The selected pressure basis must match the efficiency basis; motor electrical input and motor selection are not calculated.
Operating-point power estimate
For a matched pressure/efficiency basis,the air-power magnitude is Pair=QΔp W and the estimated fan shaft power is Pshaft=QΔp/η W. Thus with Q in m³/s and Δp in Pa,the result is watts because Pa·m³/s=N·m/s=W.
The U.S. Department of Energy fan test-procedure material distinguishes static air power for relevant unducted configurations from total air power for ducted configurations. Mixing pressure and efficiency definitions creates a physically inconsistent estimate.
The official ISO catalogue lists ISO5801:2017,edition3 as Published but to be revised,with Amendment1:2025 and a replacement project under development. It governs fan performance testing using standardized airways;this simple calculation is not an ISO5801 test or certified conversion.
Mechanical horsepower uses the NIST SP811 value 1hp(550ft·lbf/s)=745.6999W. “hp” here is not metric horsepower or electrical horsepower.
No universal efficiency or motor factor: the removed fan-type efficiency ranges and 1.15–1.25 motor multiplier were not adequate for selection. Use the certified fan curve/test point,drive and motor efficiencies,service factor,duty,starting/overload behavior,ambient/temperature,applicable electrical code and manufacturer data.
Sources:DOE fan/blower test-procedure material;ISO5801 status/scope;NIST power conversions.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
