Traditional industrial washing machines use multiple dual speed AC motors for speed regulation, which are widely used due to their simple structure, durability, and low cost. But its disadvantages are poor speed regulation performance, large speed fluctuations, and high vibration. With the development of power semiconductor technology, in recent years, AC frequency converters have been widely used in industrial washing machines. Industrial washing machines have increasingly high requirements for frequency converters, which can meet the technical difficulties of high starting torque, multi-stage speed, wide voltage range, automatic slip compensation, and fast and powerful communication methods required by industrial washing machines. And it has stable performance and can adapt to various complex high temperature and high humidity environments.
Working principle of industrial washing machine
Composition of the electrical control system for CNC engraving machine
A fully automatic industrial washing machine refers to a high-capacity washing machine that has functions such as initial washing, washing, rinsing, bleaching, and dehydration, and can automatically switch between these functions without the need for manual operation.
Industrial washing machines are mainly composed of components such as outer drum, rotary drum, transmission part, electrical control cabinet, left and right sealing covers, pipeline instruments, and drain valves. The structure of industrial washing machines generally adopts a horizontal drum type, and both the inner and outer drums are made of high-quality stainless steel refined, which is flat, bright, corrosion-resistant, has little wear on fabrics and no damage, and has a long service life; The inner cylinder door cover of the industrial washing machine is equipped with a stainless steel safety locking mechanism, and the outer cylinder door cover is equipped with a travel switch for safe and reliable operation. The working principle of a fully automatic industrial washing machine is that, under the unified scheduling and management of a timing controller, the asynchronous motor is controlled by a frequency converter to continuously perform forward and backward rotation to achieve asynchronous movement of water and clothes, thereby causing water and clothes to rub and knead against each other, achieving the purpose of washing.
Transmission system of industrial washing machine
The transmission system is an extremely important component of industrial washing machines, as it mainly provides power support for the washing machine and participates in the entire washing process. The transmission system consists of an electric motor and various variable speed mechanisms. Nowadays, frequency converters are mainly used, which significantly simplifies its components. Generally, it is composed of frequency converters, asynchronous motors, pulleys, and transmission belts. And throughout the entire washing stage, with the automatic frequency adjustment of the frequency converter, a constant torque variable speed (stepless speed regulation) without impact or intermediate transition devices (gearbox, transmission device or coupling, clutch, etc.) is achieved, which significantly reduces the energy consumption of the washing process.
The washing process of industrial washing machines: First, add water, wash in forward and reverse directions. After washing, drain the water and enter the dehydration stage. The dehydration stage includes three processes: uniform distribution, medium dehydration, and high dehydration. Uniform distribution refers to rotating the clothes in a forward direction at a higher speed than the washing process, with or without water, so that the clothes are evenly attached to the inside of the drum of the washing machine, making the subsequent dehydration process smooth; After drainage, increase the speed to enter the medium speed dehydration process, and then enter the high-speed dehydration process to reduce the moisture content of the clothes to the required level. Industrial washing machines require frequency converters to provide high torque, multi speed, wide voltage range, and automatic slip compensation. The main function of the frequency converter in this system is to adjust the washing machine speed, so that the washing machine is in a low-speed state during the washing cycle and has a very smooth torque. During the dehydration cycle, it has a high rotational speed. It is also possible to flexibly set the frequency, which is beneficial for speed regulation. In this way, the system can operate stably, reduce mechanical wear, and extend the service life of industrial washing machines. The Dongli Kechuang CT100 series frequency converter has excellent performance such as high starting torque, low operating current, and complete fault protection measures.
This frequency converter adopts a unique wide voltage design of 320V-460V, and the starting torque can reach 150% of the rated torque at 0.25Hz. The automatic torque boosting function can achieve low-frequency high output torque control under v/f control mode. The 16 segment speed can meet the multi-stage speed control mode in various occasions, with a wide speed range, no stall during acceleration and deceleration, and stable speed throughout the entire process.
The frequency converter is based on a DSP control system and adopts domestically leading PG free vector control technology, combined with multiple protection methods, which can be applied to asynchronous motors and provide excellent driving performance. The product has greatly improved customer usability and environmental adaptability in terms of air duct design, hardware configuration, and software functionality.
Technical Features
◆ High reliability selection: Key components are all from well-known domestic and foreign brands, among which the inverter module uses Infineon's fourth generation module. The higher module junction temperature can meet the requirement of 50 degrees Celsius ambient temperature without derating use!
◆ Large redundancy design: Through strict calculation and experimental verification, key components are designed with large margins to ensure the long-term stability of the entire machine in harsh environments.
Optimized vector control: domestically leading speed feedback free vector control with high low-frequency torque and fast torque response.
◆ Software current and voltage limiting function: Good voltage and current limiting, effectively limiting key control parameters to reduce the risk of inverter failure.
Strong environmental adaptability: With a high overall overheating point, independent air duct design, and thickened three proof paint treatment, it is more suitable for long-term operation in outdoor oil fields.
◆ Speed tracking restart function: achieve smooth start of rotating motors without impact
◆ Automatic voltage adjustment function: When the grid voltage changes, it can automatically maintain a constant output voltage
Comprehensive fault protection: overcurrent, overvoltage, undervoltage, overtemperature, phase loss, overload and other protection functions
◆ Multiple braking modes: Provides multiple braking modes to ensure stable, accurate, and fast system shutdown
Conclusion
Industrial washing machines need to automatically switch between different speeds to meet the speed requirements of different process stages. The multi-point VF function of the frequency converter can achieve low-frequency and low current control during the washing stage and high-speed deep weak magnetic control during the high stripping stage; Multi speed can meet the speed control of up to eight segments by switching between three multi speed terminals. The popularity of frequency converters in industrial washing machines has epoch-making significance for the craft washing machine industry.