The point along the pump performance diagram at which the efficiency is at its highest is recognize as the best efficiency point or BEP for short. To put it another way, the BEP is the point at which the pump operates at its highest possible level of efficiency. For example, centrifugal water pump or any pumping system needs to operate at or close to the BEP for the pump in order to function properly. However, in order to achieve this ideal procedure, there are a great many factors to take into account and issues to circumvent. When we examine the pump curves that are near to one another, we see that the intersection indicates that the pump is capable of producing zero flow at 41 meters and a maximum flow of 2100 liters per minute at 23 meters. If this is the case, then why is the pump able to create 2300 l/min while it is not being controlled, yet it is unable to produce flow at a particular point? The flow and pressure that are generated by the pump are subject to the configuration of the system in which the pump is positioned. 
The pumps themselves are not regarded to be distinct products. Only when considered in the context of the whole system. It is essential to double check this information because the frequency has a direct bearing on the speed at which the motor operates (refer to the table below), and different countries operate on different frequencies. For instance, the United Kingdom operates at 50Hz while the United States operates at 60Hz. In the same way that a gearbox can slow down a gear, motors can likewise have varied pole counts to achieve the same effect. Because the speed of the motor is equivalent to the speed of the pump's impeller, the flow rate and pressure that are produced by the pump are directly influenced by the speed of the motor. When compared to a pump operating at 50Hz, one operating at 60Hz generates 20% greater flow and pressure, which enables the use of a different pump for the same application. It is necessary to have an understanding of the total dynamic head in order to comprehend the location on the curve where the pump operates (TDH). The overall pressure that must be present for the pump to function. For pumping applications, it is necessary to have an awareness of the distinction between friction loss and height in order to be able to calculate the dynamic total head
The following components make up the total dynamic head (TDH):
- The height differential between the pump and the discharge point is referred to as the hydrostatic head. In most cases, it is a predetermined distance that must be computed as the greatest possible distance.
- The height difference between the fluid and the pump inlet is referred to as the suction lift. The worst-case scenario, which is the lowest level of liquid in the tank, should be used in the calculation of this.
- Friction loss is the overall loss that takes place as a result of the movement of fluid from the suction pipe to the point of discharge. When fluids pass through bends, valves, and tubes, losses occur because the fluids lose energy and momentum as a result of the passage through these obstacles. Anything that gets in the way of the fluid causes a drop in pressure. When a fluid has a higher viscosity, the amount of energy that is lost during movement is proportionally greater, as is the amount of energy that is required to keep the fluid in motion.
Historically, pumps were utilized to move water for various purposes, including drainage and irrigation. It was essential that the pump be able to increase the water level from a lower level to a higher level.
Head is currently more commonly referred to as differential head (or just head), and even though modern pumps are used for a broad variety of applications, pump performance is still typically described using this word. Today, greater emphasis is placed on the pressure differential that exists between the inlet and outlet of the pump. This pressure differential is something that may be changed by the design of the pipeline as well as the arrangement of the valves. A centrifugal pump's displacement will decrease as the pressure it must overcome increases, which will result in the pump having no output at a given head pressure. On the other side, when there is no opposing head, the pump is able to reach the greatest power that is possible due to the design of the pump, the selection of the impeller, and the rotational speed of the pump. These two locations on the pump curve are used to determine a performance range that spans between them. Either by replacing the pump's impeller or by altering the speed at which it rotates, it is possible to improve a pump's performance while maintaining the same overall design. The "tombstone" format is commonly used by manufacturers to list the range of possible widths. It demonstrates the discharge pressures and capacities covered by the pump design at a predetermined number of rotating speeds for a variety of impeller sizes and pump casing designs. 
These are shown at a range of various speeds. The real pump curve for the chosen speed, impeller size, and casing design is shown by the top line of the graph for each component or characteristic. The behavior of a centrifugal pump when it is isolated from the other plant equipment is represented by the pump curve. The impedance of the system in which it is put is what determines the real behavior of the component. Pipe pressures, frictional losses further downstream, and the static pressure near the pipe's inlet or exit. The "system curve" is the name given to the graphical representation of these various components. This demonstrates how the discharge pressure, which is measured in the position occupied by the pump, rises as the flow rate rises.