Pump Affinity Laws Calculator
Calculate pump performance changes with speed or impeller diameter changes.
Pump Affinity Laws
Law 1: Flow
Q2/Q1 = N2/N1 = D2/D1
Law 2: Head
H2/H1 = (N2/N1)^2 = (D2/D1)^2
Law 3: Power
P2/P1 = (N2/N1)^3 = (D2/D1)^3
VFD Energy Savings
A 20% speed reduction = 49% power reduction
A 50% speed reduction = 87.5% power reduction
Note: Minimum speed typically 30-40% for cooling