Variable frequency energy saving
The energy-saving effect of frequency converters is mainly reflected in the application of fans and pumps. After adopting frequency conversion speed regulation for fan and pump loads, the power saving rate is 20% to 60%. This is because the actual power consumption of fan and pump loads is basically proportional to the cube of the speed. When the average flow rate required by the user is small, using frequency conversion speed regulation to reduce the speed of fans and pumps results in a very significant energy saving effect. Traditional fans and pumps use baffles and valves for flow regulation, with the motor speed remaining basically constant, resulting in little change in power consumption. Statistics show that fan and pump motors account for 31% of the national electricity consumption and 50% of industrial electricity consumption. Using frequency conversion speed regulation devices on such loads is of great significance. Currently, successful applications include constant pressure water supply, various types of fans, central air conditioning, and hydraulic pumps.
Application in automation systems
Because the frequency converter has a built-in 32-bit or 16-bit microprocessor, it has a variety of arithmetic logic operations and intelligent control functions, and the output frequency accuracy is 0.1%~0.01%. It also has complete detection and protection links. Therefore, it is widely used in automation systems. For example: winding, stretching, metering and guiding in the chemical fiber industry; flat glass annealing furnace, glass kiln stirring, edge pulling machine and bottle making machine in the glass industry; automatic feeding and batching system of electric arc furnace and intelligent control of elevators, etc. Applications of frequency converters in improving process level and product quality: CNC machine tool control, automobile production line, papermaking and elevators. [5]
Applications in improving technological level and product quality
Variable frequency drives (VFDs) can also be widely used in the control of various mechanical equipment such as conveyors, cranes, extruders, and machine tools. They can improve process levels and product quality, reduce equipment impact and noise, and extend equipment lifespan. Adopting VFD speed control simplifies mechanical systems, makes operation and control more convenient, and in some cases can even alter existing process specifications, thereby enhancing the overall functionality of the equipment.
For example, in textiles and many other industries, the temperature inside a setting machine is regulated by changing the amount of hot air supplied. Hot air is typically supplied using a circulating fan, and since the fan speed is constant, the amount of hot air supplied can only be adjusted using a damper. If the damper malfunctions or is improperly adjusted, the setting machine will become uncontrollable, thus affecting the quality of the finished product.
High-speed startup of circulating fans causes severe wear between the drive belt and bearings, making the drive belt a consumable item. By adopting variable frequency speed control, temperature regulation can be achieved automatically by adjusting the fan speed through the inverter, resolving product quality issues. Furthermore, the inverter can easily enable low-frequency, low-speed fan startup, reducing wear between the drive belt and bearings, extending equipment lifespan, and saving up to 40% in energy.
Achieve soft start of motor
Hard starting of a motor not only severely impacts the power grid but also places excessive demands on its capacity. The large current and vibration generated during startup cause significant damage to baffles and valves, severely shortening the lifespan of equipment and pipelines. However, by using a frequency converter, its soft-start function allows the starting current to change from zero, with the maximum value never exceeding the rated current. This reduces the impact on the power grid and the demand on power supply capacity, extends the lifespan of equipment and valves, and also saves on equipment maintenance costs.
