The role of variable frequency speed regulation technology in screw pump machine

When the motor is directly started at rated frequency and rated voltage, the rotor winding cuts the rotating magnetic field at synchronous speed. The rotor electromotive force and current are both very large, and its starting current can reach 4-7 times the rated current, which will have an impact on the power supply and cause fluctuations in the grid voltage. Due to the fact that starting is a process (when an asynchronous motor starts at full voltage, it takes only 0.25 seconds to accelerate from a static state to its rated speed), it often has an impact on the mechanical load, shortening the service life of the mechanical transmission part. In the pump fluid pipeline system, it can also cause water hammer effect, which can damage the pipeline. After installing and using the frequency converter, its output frequency can start from very low frequencies (such as 0Hz), and the speed of frequency rise can also be set, allowing for the free extension of the startup process. Generally, the set frequency is reached within 0-5s, so that the rotor winding cuts the rotating magnetic field at a very low synchronous speed, and the starting current is limited within the range, thereby weakening the mechanical impact and eliminating the water hammer effect. In addition, after using a frequency converter, the average speed of the pump decreases, the average torque decreases, and the wear of the bearings also decreases, which extends the working life of the pump and reduces the labor intensity of the operators. At the same time, the noise during the operation of the pump is also reduced, which improves the working environment for the operators. Before adopting frequency conversion regulation, surplus energy was only circulated through bypass valves to adjust the hydraulic and energy balance of the system, resulting in serious energy waste. After adopting frequency conversion regulation, the actual load of the motor (the required actual load is the operating load of the pump) is reduced through the drag of the frequency conversion speed control device, thereby saving energy, optimizing the system's operating efficiency, and avoiding the problem of "; Big horse pulling small car; The situation. Due to the use of a frequency conversion system for soft start and soft stop of the oil pump unit, the impact during the start-up process is reduced, and the maintenance cycle of the oil pump is extended. After frequency conversion, the unit operates at lower speeds compared to before, and the wear of the pump shaft and bearings is reduced. Extending the lifespan of vulnerable components such as bearings and mechanical seals in oil pumps, while reducing noise during operation, not only achieves significant direct economic benefits, but also has good indirect social benefits.