Glossary of Terms Used
This is the required duty point entered by the user.
This is the actual operating duty for the fan.
Fan Input Power or Absorbed Power
This is the power consumed by the impeller - it excludes all losses due to the internal contents of the unit - fans, controls, power supplies etc. This is the power to be used in the calculation of Fan Efficiency. This is calculated at the selected duty point for the fan.
For a direct drive fan the Motor Output Power equals the Impeller Power which in Fan Selector as Fan Input Power or Absorbed Power, i.e. the power absorbed by the impeller.
Maximum Fan Input Power
This is the maximum power taken by the impeller on its performance curve, unless the exact duty point is chosen where this occurs the Fan Input Power will always be lower.
Motor Input Power
ISO5801:1997 (BS848 Pt: 1:1997) definition: The electrical power supplied at the terminals of an electric motor drive.
The difference between Motor Input Power and Fan Input Power (Absorbed Power) are a measure of the losses both mechanical and electrical within the motor.
Nuaire Selector calculates the Motor Input Power from the tested Fan Input Power (Absorbed Power) and the motor manufacturers quoted efficiency percentages.
This is the power consumed by the equipment that you actually pay for - it includes all losses due to the internal contents of the unit - fans, controls, power supplies etc. This is the power to be used in the calculation of Specific Fan Power. This is calculated at the selected duty point for the fan.
Specific Fan Power
Not actually a power rating, but a ratio that quantifies how much power is used to move a unit air quantity through a given HVAC system. It is quoted as Watts per litre per second. The power used in this calculation is the Motor Input Power.
Nominal Motor Rating
This is the rated power of the motor in accordance with IEC 34-1.
For fans the Nominal Motor Power is taken as the rating for the absorbed power of the fan.
The Fan Efficiency is the ratio of the power transferred to the airflow and the power used by the fan. It is calculated as the air volume flow (m3/s) multiplied by the total pressure (Pa) divided by the Fan Input Power.
Nuaire Selector quotes the motor manufacturers efficiency percentages.