[h=Hydraulic Pump Power]3[/h] The ideal hydraulic power to drive a pump depends on the mass flow rate, the liquid density and the differential height

- either it is the static lift from one height to an other, or the friction head loss component of the system - can be calculated as
Ph = q ρ g h / (3.6 106)(1)
where
Ph = power (kW)
q = flow capacity (m3/h)
ρ = density of fluid (kg/m3)
g = gravity (9.81 m/s2)
h = differential head (m)
[h=Shaft Pump Power]3[/h] The shaft power - the power required transferred from the motor to the shaft of the pump - depends on the efficiency of the pump and can be calculated as
Ps = Ph / η (2)
where
Ps = shaft power (kW)
η = pump efficiency