The head and flow of the pump are known. How do you calculate the power of the pump?
- Aug 17, 2017 -

Pump power refers to the power of the circuit, is an important parameter of the pump.

Pump power usually refers to the input power, that is, the original motive to the pump shaft power, so also known as Shaft, with P.

Pump power calculation is: Pump lift and mass flow and the product of gravity.

Pe=ρg QH W/pe=γqh/1000 (KW)

RHO: Pump liquid density ($literal)

Gamma: Heavy Γ=ρg (N/M3) of pump-conveying liquids

G: Gravitational acceleration (m/s)

Mass flow qm=ρq H or S

Below, take the hydraulic pump as an example, to discuss the specific method and formula of the pump power calculation.


(1) The displacement of the hydraulic pump is known to be 136 ml/rpm, the maximum operating pressure of the system is $number kgf/cm2, the required power of the computing systems and the power of the selected motor.

The output flow of the pump is equal to times the speed, namely:

= q N = 136 (ml/RPM) x970 turn/min

= 131920 (ml/min)

= 131.92 (L/min)

System Required Power

Considering the efficiency of the pump, the motor power is generally 1.05 ~ 1.25 times times the required power.

ND = (1.1. $number) N =28.4 (KW)

Check the motor manual, the selected motor power of 30kW is more suitable.


(2) The existing hydraulic pump is known to be 136 ml/rpm, the matching motor is 22kW, and the computing system can achieve the highest working pressure.

known = Q n=131.92 (L/min), ND =22kw

Deform a formula

Considering the efficiency of the pump, the maximum operating pressure of the system can not exceed the kgf/cm2.