Before purchasing a water pump, many users think that the lower head working condition chooses a higher head water pump to use a wider range of heads. In this misleading misunderstanding, when buying a water pump, the pump head selected is very high. In fact, for centrifugal water pumps, when the pump model is determined, its power consumption is proportional to the actual pump and flow rate. When the pump uses a lower head, the flow rate will increase; thus the current is higher, the smaller the flow rate, and the lower power consumption. On the contrary, lower the head, more flow, more power consumption. Therefore, in order to prevent the motor from being overloaded, it is generally required that the actual calibrated head of the pump pumping head should not be less than 60%. Therefore, when a high-lift pump is used for a low-lift, the motor is prone to overload and heats up, and in severe cases, the motor is burned out. If it is used in emergency, it must be adjusted with a water outlet valve installed in the outlet pipe. A self-operated regulating valve (or wood block, and other methods) can usually be used to reduce the water flow rate and prevent the motor from overloading. Pay attention to the temperature of the motor. If the motor is overheated, a small water outlet flow or shutdown in time can avoid burning the motor. Some users force to reduce the flow by reducing the power supply voltage, which will increase the motor load. In fact, on the contrary, the unit outlet pipes of centrifugal pump irrigation and drainage stations are equipped with valves to reduce the motor load. The valve should be closed before the pump is stopped. After the pump is started, the valve should be gradually opened so that it will not overcurrent when it starts.
It should be installed like this: install the low-lift pump in front of the high-lift pump, that is, the output of the low-lift pump is sent to the inlet of the high-lift pump. There is a problem in that the outlet pressure of the low-lift pump cannot exceed the upper limit of the inlet pressure of the high-lift pump , Otherwise it is prone to overpressure and water leakage.
