Pump shaft power calculation formula

Flow rate × head × 9.81 × medium specific gravity ÷ 3600 ÷ pump efficiency

Flow unit: cubic/hour,

Lift unit: meters

P=2.73HQ/η,

Among them, H is the head in m, Q is the flow rate in m3/h, and η is the efficiency of the  deep well vertical turbine pump. P is the shaft power in KW. That is, the shaft power of the pump P=ρgQH/1000η(kw), where ρ =1000Kg/m3,g=9.8

The unit of specific gravity is Kg/m3, the unit of flow is m3/h, the unit of head is m, 1Kg=9.8 Newtons

Then P=specific gravity*flow*head*9.8 Newton/Kg

=Kg/m3*m3/h*m*9.8 Newton/Kg

=9.8 Newton*m/3600 seconds

=Newton*m/367 seconds

=Watts/367

The above derivation is the origin of the unit. The above formula is the calculation of water power. The shaft power is divided by the efficiency.

Suppose the shaft power is Ne, the motor power is P, and K is the coefficient (reciprocal of efficiency)

Motor power P=Ne*K (K has different values when Ne is different, see the table below)

Ne≤22 K=1.25

twenty two

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Calculation formula of slurry pump shaft power

Flow rate Q M3/H

Lift H m H2O

Efficiency n %

Slurry density A KG/M3

Shaft power N KW

N=H*Q*A*g/(n*3600)

Motor power also needs to consider transmission efficiency and safety factor. Generally, the direct connection is taken as 1, the belt is taken as 0.96, and the safety factor is 1.2.

Pump Efficiency and its Calculation Formula

Refers to the ratio of the effective power of the deep well vertical turbine pump to the shaft power. η=Pe/P

The power of a pump usually refers to the input power, that is, the power transmitted from the prime mover to the pump shaft, so it is also called shaft power and is represented by P.

Effective power is: the product of the pump head, mass flow rate and gravity acceleration.

Pe=ρg QH (W) or Pe=γQH/1000 (KW)

ρ: Density of liquid transported by the pump (kg/m3)

γ: The gravity of the liquid transported by the pump γ=ρg (N/m3)

g: acceleration due to gravity (m/s)

Mass flow rate Qm=ρQ (t/h or kg/s)

Introduction to the Efficiency of Pumps

What is pump efficiency? What is the formula?

Answer: It refers to the ratio of the effective power of the pump to the shaft power. η=Pe/P

The power of a deep well vertical turbine pump usually refers to the input power, that is, the power transmitted from the prime mover to the pump shaft, so it is also called shaft power and is represented by P.

Effective power is: the product of the pump head, mass flow rate and gravity acceleration.

Pe=ρg QH W or Pe=γQH/1000 (KW)

ρ: Density of liquid transported by the pump (kg/m3)

γ: The gravity of the liquid transported by the pump γ=ρg (N/m3)

g: acceleration due to gravity (m/s)

Mass flow Qm=ρQ t/h or kg/s