Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 23, 2023

The pump horsepower calculator is used to calculate the pump power, which is the amount of power supplied to the shaft. A pump is a piece of hydraulic machinery that uses mechanical action to transport fluid. Maintaining the city's water supply, heating, ventilation, air conditioning (HVAC), hydraulics and pneumatics, and energy-generating are all examples of its applications.

Pump parameters
Discharge (Q)
Differential head (H)
Density of fluid (ρ)
Revolutions (N)
Acceleration due to gravity (g)
Pump characteristics
Efficiency (η)
Hydraulic power (Pₕ)
Shaft power (Pₛ)
Specific speed (Nₛ)

Types of Pump Power

Pump power is divided into two categories: shaft and hydraulic power.

The casing, impeller, delivery pipe and suction pipe are the most typical parts of a pump. The suction end of the pipe is used to draw fluid, which is then transported across the body of the pump to the delivery end. Depending upon the nature of the pump, the impeller, which is located inside the casing, operates in a rotational or reciprocating motion to accomplish this. The impeller is attached to a shaft that is powered by an electric motor.

The power applied to obtain the head and volumetric flow rate is referred to as pump shaft power. It is determined by the volumetric flow rate Q, the differential head H, the fluid density ρ, efficiency η, and the gravitational constant g. That is, mathematically: Ps = Q * H * ρ * g / η

Therefore, hydraulic power can be calculated as follows: Ph = Q * H * ρ * g

As a result, the efficiency can be expressed as the ratio of hydraulic power to shaft power: η = Ph / Ps

The equations above are true if the parameters have the units listed below.

  • Q = Volumetric flow rate is measured in m^3/s.
  • H = Head it is measured in metres.
  •  η = Efficiency is rated on a scale (0 to 1).

We are aware that most pumps do not work at 100% efficiency. The particular speed parameter is used to compare the pump's performance to the ideal situation, which is a geometrically comparable pump that delivers 1 cubic metre of fluid per second against 1 metre of the head. The particular speed Ns is a dimensionless quantity that may be calculated using the following equation:

Ns = N * Q0.5 / (g * H)0.75

Where N = pump's rotational speed in radians per second.

While Ns is dimensionless, its value is affected by the units system used for its inputs. The calculator that produces dimensionless output for a specified speed uses the above form of the equation. However, to use with English units, a simplified version of the equation was produced that did not include the acceleration due to gravity g. Mathematically,

Ns = N * Q0.5 / H0.75

For the above equation, the user must verify that the units used are consistent. Consequently,

  • Q = Discharge in gallons per minute;
  • H = Head in feet; and
  • N = Speed in rotations per minute.

How do I calculate shaft power?

To determine a pump's shaft power, use the following formula:

  • Step 1: The discharge or fluid flow rate Q, should be entered.
  • Step 2: Enter the differential head H in this position.
  • Step 3: Fill in the fluid's density ρ
  • Step 4: Calculate the pump's efficiency η
  • Step 5: The shaft and hydraulic powers are then calculated by the pump horsepower calculator.
  • Step 6: Additionally, to determine the pump's exact speed:
  • Step 7: N is the number of revolutions per minute that the pump is running.
  • Step 8: The hydraulic horsepower calculator will provide you with the pump's particular speed.

How can I find out how much hydraulic power a pump has ?

To find out how much hydraulic power a pump has, do the following:

  • Step 1: Multiply the differential head H by the discharge Q.
  • Step 2: Multiply the result by the fluid's density as well as the acceleration due to gravity.

Become familiar with plenty of similar concepts of physics along with well designed calculator tools complementing the concept on a trusted reliable portal for all your needs.

FAQs on Pump Horsepower Calculator

1. What is the shaft power of a pump?

Pump shaft power is the amount of energy necessary to turn the pump's shaft in order to provide a specific differential head.

2. How does a pump's horsepower (HP) work?

Horsepower is defined as 550-foot pounds per second (746 watts) of electrical power. The minimum power required for a pump to convey water throughout a system, or the power required if the pump were 100% efficient, is referred to as water horsepower.

3. How can you find out how much horsepower a pump has?

To find out how much power a pump's shaft has, do the following:

  • Step 1: Multiply the differential head H by the discharge Q.
  • Step 2: Multiply the result by the fluid's density as well as the acceleration due to gravity.
  • Step 3: Divide the result from the pump's efficiency.

4. A 2 HP pump can transport how much water?

Each intake line will receive a maximum flow of 73 gallons per minute. Each 1.5-inch intake line has a maximum flow of 42 gallons per minute.

5. How high can a one-horsepower pump push water?

A one-horsepower sump pump has a long vertical and horizontal reach, making it suitable for both residential and commercial applications. These pumps have a flow rate of 19 gallons per minute and can pump water from wells as deep as 200 feet.