When the centrifugal water pump is started at full pressure, it takes only about 10 minutes to go from a static state to a rated speed, and when the pump is stopped, the closing time of the bottom valve is about 10 minutes. Therefore, the flow rate of the submersible pump will change sharply during the process of starting and stopping at full pressure, and the inertia of the water will cause the pressure of the pipeline to rise and fall sharply alternately, that is, the phenomenon of water hammer. Equipment operation brings unsafe factors. In order to solve this problem, we choose Shanghai Renault Moon series soft starter with slow stop function and high cost performance. To prevent the control line from being too long to generate interference signals and affect the normal operation of the equipment.
Soft starter selection and installation Soft starter setting The soft starter is equipped with a digital display and a control button. There are digital displays during the parameter setting process, and the adjustment is very convenient. Its specific settings are as follows: starting mode 2. The torque required to drive the water pump is in the square relationship with the speed, so it is very suitable to choose the current limiting mode. When the current limiting value is set in the current limiting mode, the starting time depends on the setting value of the current limiting, and a lower value should be set on the premise of smooth starting to reduce the impact on the power distribution system. At the same time, the extension of the starting time should make the pump No water hammer occurs during starting. The soft stop time is to prevent the water pump from generating water hammer during the stop process, and the stop time is set to . Choose a soft starter according to the power of the water pump.
The pumping station requires remote button operation, so the control circuit adopts an intermediate relay to control the soft start stop time, and the soft stop time setting table in the current limiting mode. The experiment proves that the switching power supply works stably, the output ripple is small, and the transformer does not generate heat. The system has good working performance.