Many operators believe that the lower the pumping head, the smaller the motor load. Under the misunderstanding of this misunderstanding, when choosing a pump, the pump head is often selected very high. In fact, for centrifugal pumps, when the pump model is determined, its power consumption is proportional to the actual flow of the pump. The flow of the pump will decrease with the increase of the head. Therefore, the higher the head, the smaller the flow and the smaller the power consumption. Conversely, the lower the head, the larger the flow, and the greater the power consumed.
Therefore, in order to prevent the motor from being overloaded, it is generally required that the actual pumping head of the pump should not be lower than 60% of the nominal head. Therefore, when the high head is used for pumping at too low head, the motor is easily overloaded and generates heat, and the motor can be burned in severe cases. For emergency use, you must install a gate valve on the water outlet pipe to adjust the water output (or block the small water outlet with wood or other objects) to reduce the flow and prevent the motor from overloading. Pay attention to the temperature rise of the motor. If you find that the motor is overheating, turn off the flow of the water outlet or shut down. This point is also easy to cause misunderstanding. Some operators believe that blocking the water outlet and forcing a reduction in flow will increase the load on the motor. In fact, the opposite is true. The outlet pipe of a regular high-power centrifugal pump drainage and irrigation unit is equipped with a gate valve. In order to reduce the motor load at the start of the unit, the gate valve should be closed first, and the gate valve should be gradually opened after the motor starts.