Pump discharge flow, head

The head and flow rate are determined based on the process requirements. Once the pump is selected, flow rate and head are related to each other: when the head is much greater than the pipe resistance, the flow rate increases, which can cause the motor to overheat and get damaged; when the head is less than the pipe resistance, the flow rate decreases, or the fluid may not even reach the desired location. The outlet pressure is generally equal to the head minus the pipe resistance at the measurement point. The rated current refers to the current corresponding to the rated power under normal operation, while the protection current is generally 6-7 times higher than the rated current (starting current). Your questions are very varied

In simple terms, the relationship between flow rate and head can be determined from the performance curve; outlet pressure = inlet pressure + head x specific gravity. An overload thermal protection relay is used (with a current level of 1.1–1.2 times the rated current), and it is necessary to avoid the current levels during startup

Yang Cheng and flow rate are determined by the pump’s performance curve, while the outlet pressure is calculated based on fluid dynamics principles

Just to add some excitement, here’s a fake article; P “The relationship among the head, flow rate, and outlet pressure of centrifugal pumps, as well as the relationship between the pump’s rated current and its protection current.” The head of the pump can be roughly considered as the pressure at the pump outlet; thus, this simplifies the relationship to one between flow rate and the pump outlet pressure. When the flow rate exceeds the rated value, it may be due to a decrease in pressure, causing the current to increase. If the current exceeds the rated value, an overcurrent protection must be installed to shut down the system in case of overload. Otherwise, the motor will be damaged. Therefore, during control, the outlet valve is used to regulate the operating pressure of the pump; when the pressure drops below the rated value, the flow rate increases, as does the current. Generally, the higher the pressure of a centrifugal pump (slightly above the rated pressure due to operational limitations), the lower the flow rate and the lower the current. It is worth noting that when the current is at its lowest, the pump flow rate is also zero. At this point, the work done by the impeller causes the liquid medium to heat up, and it can even reach a boiling point. As it is a knockoff version, it is for reference only.

Outlet pressure = Inlet pressure + (Density * Head * 9.81)