A lot of users before the purchase of water pumps, that the lower head operating conditions to choose a higher head of the pump using a wider range of lift. In this misleading misunderstanding, the purchase of pumps, the selection of pump head is very high. In fact, for centrifugal pumps, when the pump model is determined, its power consumption is proportional to the actual pump and flow size. The pump uses a lower lift when the flow rate will increase; Conversely, lower the head, the greater the flow, the greater the power consumption. Therefore, in order to prevent motor overload, it is generally required that the actual calibration head of pump pumping head should not be less than 60%. Therefore, when the high lift pump for low lift, easy to overload the motor is easy to heat, serious situation of the motor was burnt out. If the emergency is used, it must be adjusted with a water outlet valve installed in the outlet pipe to usually adopt a self regulating valve (or wood block, and other methods) to reduce the effluent flow and prevent the motor from overloading. Pay attention to the temperature of the motor, if the motor overheating, small outlet flow or shutdown can be avoided in time to burn the motor. Some users to reduce the power supply voltage to force the reduction of traffic, which will increase the motor load. In fact, on the contrary, the centrifugal pump station unit outlet pipe are equipped with a valve to reduce the motor load of the purpose of the pump should be closed before the valve, the pump started, gradually open the valve to start it will not exceed the current.