For motor products, when they are produced in strict accordance with design parameters and process parameters, the speed difference of motors of the same specification is very small, generally not exceeding two revolutions. For a motor driven by a single machine, the speed of the motor is not too strict, but for a device or equipment system driven by multiple motors, the control of the motor speed is very important.
In the traditional transmission system, it is necessary to ensure a certain relationship between the speeds of multiple actuators, including ensuring that the speeds between them are synchronized or have a certain speed ratio, which is often realized by mechanical transmission rigid coupling devices. However, if the mechanical transmission device between multiple actuators is large and the distance between the actuators is long, it is necessary to consider the use of a non-rigid coupling transmission control method with independent control.
With the maturity of the frequency converter technology and the expansion of the scope of use, the programmable controller can be used to control it, so as to adapt to the different requirements of the speed control flexibility, accuracy and reliability in the transmission system. In actual production, the application of PLC and frequency converter for speed control can also better achieve the expected synchronization or given speed ratio control requirements.
The energy-saving effect of the frequency converter is mainly manifested in the application of fans and water pumps. After the fan and pump load adopts frequency conversion speed regulation, the power saving rate is 20% to 60%. This is because the actual power consumption of the fan and pump load is basically proportional to the cube of the rotation speed. When the average flow required by the user is small, the fan and pump use frequency conversion speed regulation to reduce the speed, and the energy saving effect is very obvious. The traditional fans and pumps use baffles and valves to adjust the flow, the motor speed is basically unchanged, and the power consumption does not change much. According to statistics, the electricity consumption of fans and pump motors accounts for 31% of the national electricity consumption and 50% of the industrial electricity consumption. It is very important to use the variable frequency speed control device on such loads. At present, the more successful applications are the variable frequency speed regulation of constant pressure water supply, various types of fans, central air conditioners and hydraulic pumps.
The direct start of the motor will not only cause serious impact to the power grid, but also require too much capacity of the power grid. The large current and vibration generated during start-up will cause great damage to the baffle and valve, and is extremely detrimental to the service life of equipment and pipelines. After using the inverter, the soft start function of the inverter will make the starting current change from zero, and the maximum value will not exceed the rated current, which reduces the impact on the power grid and the requirements for power supply capacity, and prolongs the service life of equipment and valves. , and also save the maintenance cost of the equipment.
Since the inverter has a built-in 32-bit or 16-bit microprocessor, it has a variety of arithmetic logic operations and intelligent control functions, the output frequency accuracy is 0.1%~0.01%, and it is equipped with perfect detection and protection links. Therefore, in automation widely used in the system. For example: winding, drawing, metering and wire guide in chemical fiber industry; flat glass annealing furnace, glass kiln stirring, edge drawing machine, bottle making machine in glass industry; automatic feeding and batching system of electric arc furnace and intelligent control of elevator Wait. The application of frequency converters in CNC machine tool control, automobile production lines, papermaking and elevators has changed to improve the technological level and product quality.
The frequency converter can also be widely used in various mechanical equipment control fields such as conveying, lifting, extrusion and machine tools. It can improve the technological level and product quality, reduce the impact and noise of the equipment, and prolong the service life of the equipment. After adopting the frequency conversion speed control, the mechanical system is simplified, the operation and control are more convenient, and some can even change the original process specification, thus improving the function of the whole equipment. For example, in the setting machine used in textiles and many industries, the temperature inside the machine is adjusted by changing the amount of hot air fed into it. The circulating fan is usually used to convey the hot air. Since the speed of the fan remains unchanged, the amount of hot air sent can only be adjusted by the damper. If the damper adjustment fails or is adjusted improperly, the setting machine will be out of control, thus affecting the quality of the finished product. When the circulating fan starts at high speed, the wear between the transmission belt and the bearing is very serious, making the transmission belt a consumable item. After adopting frequency conversion speed regulation, temperature regulation can be realized by the frequency converter automatically adjusting the speed of the fan, which solves the problem of product quality. In addition, the frequency converter can easily start the fan at low frequency and low speed and reduce the wear between the transmission belt and the bearing, and can also prolong the service life of the equipment and save energy by 40%.
Post time: Jul-07-2022