(1) The impact on the head of the water pump
The commonly used motors for water pumps are 2-pole, 4-pole, 6-pole, reduction motor, and speed regulating motor. When the same type of water pump is maintained at a constant flow rate, the lower the motor speed, the lower the pump head, and the lower the outlet pressure. Therefore, high lift pumps generally choose 2-pole motors, while low lift pumps choose 4-pole and 6-pole motors. The motor speed has typical applications in pipeline centrifugal pumps.
(2) The impact on the flow rate of the water pump
The flow rate of the water pump is maintained at a constant pressure at the outlet, and the higher the speed, the greater the flow rate of the water pump. Single stage single suction centrifugal pumps of the same model may use a cutting impeller diameter instead of a smaller motor to reduce flow rate. However, low-speed motors may reduce both flow rate and pressure, making it difficult to meet the same process requirements.
(3) The impact on the efficiency of the water pump
The efficiency of a water pump indicates its effectiveness and reflects its utilization of the electric motor. The speed of the centrifugal pump motor has a disproportionate impact on efficiency, while factors such as the smoothness of the pump body, the tightness of the seal, and the layout of the pipeline affect the efficiency of the pump.
Extended Information
The flow rate of the water pump, that is, the water output, should generally not be selected too large, otherwise it will increase the cost of purchasing the water pump. It should be selected according to needs, such as the self-priming water pump used by users in their homes, and the flow rate should be selected as small as possible; Users can choose submersible pumps with higher flow rates for irrigation.
1) Choose water pumps according to local conditions. There are three types of commonly used agricultural water pumps, namely centrifugal pumps, axial flow pumps, and mixed flow pumps. Centrifugal pumps have a high head but a small water output, making them suitable for mountainous areas and well irrigation areas; Axial flow pump has a large water output, but the head is not too high, suitable for use in plain areas; The output and head of mixed flow pumps are between centrifugal pumps and axial flow pumps, and are suitable for use in plain and hilly areas.
2) Choose a water pump that exceeds the standard appropriately. After determining the type of water pump, its economic performance should be considered, especially the selection of the pump's head, flow rate, and supporting power.
It must be noted that the head indicated on the water pump label (total head) is different from the actual head at the time of use (actual head), as there will be some resistance loss when the water flows through the water supply pipe and near the pipeline. So, the actual head is generally 10% -20% lower than the total head, and the water output is correspondingly reduced.
Therefore, in actual use, it can only be estimated based on 80% to 90% of the head and flow rate indicated on the label. The selection of the matching power for the water pump can be based on the power indicated on the label. In order to make the water pump start quickly and use safely, the power of the power machine can also be slightly higher than the required power of the water pump, generally about 10% higher; If there is already power, when selecting a water pump, you can choose a water pump that matches the power of the power machine.
3) Strict procedures must be followed when purchasing water pumps.
