Fan Laws & Calculations
1 - How changing RPM affects CFM
Formula: new_CFM = orig_CFM x (new_RPM/orig_RPM)
original CFM
original RPM
new RPM
2 - How changing RPM affects static pressure
Formula: new_SP = orig_SP x (new_RPM/orig_RPM)^2
original static pressure
original RPM
new RPM
3 - How changing RPM affects horsepower
Formula: new_HP = orig_HP x (new_RPM/orig_RPM)^3
original HP
original RPM
new RPM
4 -Calculate Amps from Horsepower & Voltage
single phase
three phase
Formula: Amps = HP x 746 / (Volts x power factor x efficiency)
HP
Volts
Power Factor
Effiency %
%
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