How to Measure Break Horsepower Pump Performance Curve – A Comprehensive Guide

Measuring the break horsepower performance curve of a pump is crucial in assessing it’s efficiency and determining it’s ability to deliver the required flow rate against the total dynamic head (TDH) it needs to overcome. To calculate BHP, a simple formula involving TDH, gallons per minute (gpm), specific gravity (SG), and the pump's efficiency percentage must be applied: (TDH x gpm x SG) / (3960 x pump %). For instance, consider an example where the pump delivers 175 gpm at a TDH of 70, while the fluid being pumped possesses a SG of 0.95, and the pump's efficiency, as specified by the manufacturer's curve, is 68 percent.

How Do You Measure the Performance of a Centrifugal Pump?

Measuring the performance of a centrifugal pump involves determining it’s efficiency by converting head units and capacity into horsepower output. Capacity, in this context, is the total water output of the pump, usually measured in gallons per minute. Head units, on the other hand, are a measure of the distance between the source water and the output of the pump.

To measure the pumps performance, you must first ascertain it’s capacity. This can be done by monitoring the volume of water that the pump can discharge in a given amount of time. By quantifying this output in gallons per minute, you’ve a crucial measurement for evaluating the pumps effectiveness.

Once the capacity is established, it needs to be combined with head units. By determining this vertical lift, you can calculate the amount of energy required to lift the water, which is an essential factor in assessing pump performance.

To convert capacity and head units into horsepower output, you can utilize various equations and calculation methods. These formulas consider factors such as pump efficiency and the specific gravity of the fluid being pumped. By applying the appropriate equations, you can obtain a more accurate representation of the pumps overall efficiency and performance.

In addition to horsepower output, other key performance indicators can be measured, such as pump efficiency and NPSH (Net Positive Suction Head). Pump efficiency reflects the ratio of the pumps actual power output to the power input. NPSH represents the amount of head pressure available at the pumps inlet, which is vital for preventing cavitation.

Pump Selection: Provide a Guide on How to Select the Right Centrifugal Pump for a Specific Application. Discuss the Factors That Should Be Considered, Such as Flow Rate, Head, and Fluid Properties.

  • Flow rate
  • Head
  • Fluid properties

One of the crucial aspects of understanding pump performance is examining it’s pump curve. This curve provides valuable insights into how the pump will function concerning both pressure head and flow. To precisely analyze a pump’s performance, it’s essential to consider the specific operating speed (rpm) and the inlet/outlet diameter for which the curve is defined.

What Is a Pump Curve?

A pump curve is a graphical representation that illustrates the performance characteristics of a pump with respect to both pressure head and flow rate. It provides valuable information about how the pump will operate under different operating conditions, such as varying flow rates and pressure requirements.

This means that a change in either the speed or the diameter will result in a different pump curve. Therefore, it’s essential to have accurate and up-to-date information regarding the specific operating conditions when analyzing the pump performance.

It shows the relationship between these two variables, allowing engineers and operators to assess the pumps efficiency, capacity, and suitability for a given application. By studying the curve, one can determine the best operating point that achieves the desired flow and head requirements, as well as evaluate potential limitations or inefficiencies in the pumps performance.

The shape of the pump curve is influenced by various factors, such as the impeller design, pump size, and motor power. Generally, a pump curve starts at zero flow and zero head, representing the pumps shut-off condition. As the flow rate increases, the head also rises until it reaches the pumps maximum head, known as the shut-off head. Beyond this point, further increase in flow rate leads to a decrease in head due to hydraulic limitations.

By analyzing the pump curve, engineers can make informed decisions regarding system design and ensure that the pump is operating in an efficient and reliable manner.

Source: Understanding Centrifugal Pump Curves | M.G. Newell

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One way to measure the performance of a pump is by analyzing it’s flow rate, head, and efficiency. These three models provide users with valuable information about how the pump is functioning and can help determine if any adjustments or improvements need to be made.

How Will You Measure the Pump Performance?

To measure the pump performance, the flow rate (Q) is commonly used as a fundamental parameter. Flow rate refers to the volume of fluid passing through the pump per unit time. It’s typically measured in gallons per minute (GPM) or liters per second (L/S). By monitoring the flow rate, users can evaluate the pumps ability to deliver the desired amount of fluid efficiently. Deviations from the expected flow rate may indicate issues with the pumps internal components or external factors affecting it’s performance.

Another crucial indicator of pump performance is the head (h). Head refers to the energy exerted by the pump to raise the fluid from the inlet to the discharge point. It’s measured in units of height, such as feet (ft) or meters (m). By observing the head, users can assess the pumps ability to overcome resistance and maintain a stable flow rate. An unexpected decrease in head may suggest a blockage or wear and tear in the pump system, leading to reduced performance.

Efficiency (n) is yet another vital factor in evaluating pump performance. Efficiency represents the ratio of the actual output power delivered by the pump to the input power supplied. It’s expressed as a percentage. An efficient pump converts a higher percentage of the electrical power into useful mechanical energy, resulting in lower energy costs and improved performance. Monitoring the efficiency allows users to identify any energy losses, mechanical failures, or inefficiencies within the pump system.

In addition to these three primary analytical models, other performance parameters such as power consumption, pressure, and temperature can be measured to evaluate the pumps overall performance. Power consumption indicates the amount of electrical power required to drive the pump and can be measured in kilowatts (kW) or horsepower (HP). Pressure measurements provide insights into the force applied by the pump to move the fluid, while temperature helps monitor any overheating or thermal issues that may affect pump performance.

Regular monitoring and measurement of these performance parameters can help identify potential problems, optimize pump operation, and prevent costly breakdowns. By understanding and analyzing flow rate, head, efficiency, power consumption, pressure, and temperature, users can make informed decisions regarding maintenance, repair, or replacement of the pump, ensuring it’s reliable and efficient performance over the long term.

Pump Efficiency Curve: A Pump Efficiency Curve Is a Graphical Representation of a Pump’s Efficiency at Different Flow Rates and Heads. By Generating an Efficiency Curve for a Specific Pump, Users Can Identify the Optimal Operating Conditions That Will Maximize Efficiency and Minimize Energy Consumption.

  • A pump efficiency curve is a graphical representation of a pump’s efficiency at different flow rates and heads.
  • By generating an efficiency curve for a specific pump, users can identify the optimal operating conditions that will maximize efficiency and minimize energy consumption.

Now let’s break down the components that determine the brake horsepower (BHP) of a pump. It starts with the work horsepower (WHP), which accounts for the power required for the pump to perform it’s intended duties. In addition to WHP, another factor in the BHP calculation is the viscous horsepower (VHP), which quantifies the power consumed by the pump due to fluid viscosity. By combining these two elements, we can determine the overall power necessary for a pump to overcome the discharge pressure and fulfill it’s function effectively.

What Is the WHP and BHP of a Pump?

What’s the WHP and BHP of a pump? Brake horsepower (BHP) is the power the pump requires to overcome the discharge pressure. It’s an essential parameter in understanding the efficiency and performance of a pump. BHP is determined by adding the work horsepower (WHP) and the viscous (VHP) horsepower together.

Work horsepower (WHP) represents the actual power required to physically move the fluid through the pump. It accounts for the energy needed to create the flow and overcome any system losses. WHP takes into consideration the flow rate, fluid properties, and the pumps operating conditions. It’s a direct measure of the pumps work output.

Viscous horsepower (VHP), on the other hand, accounts for the power loss due to fluid viscosity. As fluids flow through a pump, they experience internal friction, which requires additional energy to overcome. It helps quantify the amount of power needed to compensate for the fluids resistance.

By knowing the BHP, engineers can assess the pumps energy consumption, efficiency, and ensure proper sizing for the required application. It provides critical information for selecting the appropriate motor and designing an effective pumping system.

By minimizing losses, optimizing fluid properties, and selecting the right pump, engineers can reduce energy consumption and achieve higher operational efficiency.

How to Calculate the BHP and WHP of a Pump

To calculate the Brake Horsepower (BHP) and Water Horsepower (WHP) of a pump, you can follow these steps:

1. Determine the flow rate: Measure the volume of water passing through the pump per unit time (in gallons per minute or liters per second).

2. Measure the total head: Determine the difference in pressure between the pump’s inlet and outlet. This can be done using pressure gauges or by measuring the vertical distance between the water levels before and after the pump.

3. Calculate the BHP: BHP is the power delivered by the pump to the water. Use the formula BHP = (Flow rate × Total head) / (3960 × Pump efficiency). Pump efficiency is typically provided by the manufacturer or can be estimated based on the type and size of the pump.

4. Calculate the WHP: WHP represents the useful work done by the pump, which excludes any energy losses. Use the formula WHP = (Flow rate × Total head) / 3960.

By following these steps, you can accurately calculate the BHP and WHP of a pump.

Once you’ve found the pump performance curve for your selected product and model by searching for it using the product name, the next step is to thoroughly review the information provided. This will help verify that the pump characteristics align with your specific requirements. After reviewing the information, you can proceed to print the pump curve and any additional data that may be necessary for your operations.

How Do You Find the Pump Curve?

When it comes to finding the pump curve, there are a few simple steps you can take to get the information you need quickly and efficiently. The pump curve is a graphical representation of a pumps performance characteristics, including it’s flow rate, head pressure, and power consumption.

To begin the process, you’ll first need to search for the specific product you’re looking for. This can typically be done by typing the pump name into a search field and selecting the correct product and model from the results. This will bring up a page or document with all the relevant information about that particular pump.

Once you’ve located the pumps information, the next step is to review the available data. It’s important to carefully examine all the information provided to ensure that it meets your requirements and that you’ve a clear understanding of the pumps capabilities.

This will allow you to have a physical copy of the information that you can refer to during the design or selection process. It’s also helpful to keep digital copies of these documents for future reference.

Having access to this information is essential for making informed decisions about pump selection and design, and can save you valuable time and resources in the long run.

The BHP (brake horsepower) curves provide crucial information on the power needed to run a pump at a specific position on it’s performance curve. These curves operate in tandem with the head-flow curve and vary according to the impeller size. Understanding the BHP curve is essential in ensuring efficient pump operation and performance optimization.

What Is the BHP of the Pump Performance Curve?

The BHP (brake horsepower) of a pump performance curve is a crucial aspect in analyzing the power requirements for operating a pump at specific points on the performance curve. The lines on the BHP curve correspond directly to the performance curves located above them, and these lines can differ depending on the impeller sizes being utilized.

By analyzing the BHP curve, professionals can determine the most energy-efficient operating point for the pump, ensuring maximum performance with minimal power usage.

Consequently, understanding the BHP curve allows engineers to make informed decisions regarding impeller selection, ensuring the most suitable impeller type is utilized for a given application.

The Relationship Between BHP and Efficiency in Pump Performance

The relationship between BHP (Brake Horsepower) and efficiency in pump performance is an important aspect to consider. BHP is a measure of the power required by the pump to perform it’s task.

Efficiency, on the other hand, is a measure of how well the pump converts the input power into useful output power. The higher the efficiency, the less power is wasted as heat or other forms of energy loss.

In general, there’s a direct relationship between BHP and efficiency. As BHP increases, the efficiency tends to decrease. This is because higher power requirements usually result in more energy loss due to factors like friction, turbulence, or mechanical inefficiencies.

Conversely, if the pump is operating at a lower BHP, it generally indicates a more efficient system. This means that less power is being wasted, and more of it’s being converted into useful work.

Therefore, it’s crucial to find a balance between BHP and efficiency when designing or operating a pump system. By optimizing the pump and minimizing power requirements, it’s possible to achieve higher overall efficiency, leading to cost savings and reduced energy consumption.


This measurement serves as a valuable tool for assessing the pump's performance and determining it’s suitability for specific applications. Understanding and measuring BHP empowers engineers and operators to make informed decisions regarding pump selection, maintenance, and optimization, ensuring optimal performance and cost-effective operations.

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