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Water jet, also called high pressure water jet cutting technique, is a special cold cutting and can realize cutting processing of any curves. Now it is widely used in industries like aviation, automobile, stone material, glass, metal, concrete and so on. Servo system takes its own advantages to the application in water jet cutting, which brings a lot of benefits, like high efficiency, low consumption, high cutting precision and high rate of finished products.

It is well known that torque of stepper motor is big in slow speed but it will drop sharply after it reaches above 600RPM, making stepper motor cannot be applied on occasions with high speed motion. Moreover, since positioning defects of stepper motor when it stop working will cause location errors, it cannot meet requirements of modern inkjet printers on high speed and high efficiency any longer. However, servo motor has characteristics like rapid response, high speed and high positioning accuracy, thus modern inkjet printers generally select motors of this kind as cloth feeding motor and small panel control motor, thus forming the situation of the high and medium-end market which centers on alternating servo motor system.

CNC Bending Machine is a machine to process metal plates and it mainly uses hydraulic system to blend panels into different shapes. In view of defects of the hydraulic system of traditional bending machine and characteristics of forming techniques and processes of equipment, it adopts servo drive, servo motor, and gear pump to adjust control system of flow and pressure of hydraulic system, which can reduce system energy consumption and temperature-rising of hydraulic oil, and improve operational reliability of equipment at the same time.

Illustrate the transformation process by taking dedicated servo system of injection molding machine: First, it should replace general asynchronous machine and dosing oil pump of the former system with servo motor and internal gear pump, add pressure transmitter in output direct pipes of oil pump and get rid of proportional pressure valve of the former system and corresponding amplifier board. Pick up analog signals whose pressure and flow are given from computer control of injection molding machine, transform them into 0-10V DC analog pressure signals through comprehensive processing and directly add them in input terminals of system pressure given signals and system flow given signals of servo drives, and connect pressure sensors in exit of oil pump with pressure feedback signal terminal of servo. Servo system can have PI adjustment through connected pressure and flow signals and change output torque and speed of servo motor so as to change output flow Qt and pressure p of oil pump to meet oil pressure and flow required by injection molding machine in various processes.

Fully automatic terminal crimping machine is kind of electromechanical integration machinery which integrates the three major processing procedures of the end of wiring harness, namely, cutting off, flaying. It can process a harness in an average speed of less than 1s and its flaying precision can reach to as high as 0.01ms. To meet the requirement, executive motor plays an important role. Due to its advantages, like high stability, small vibration and high precision, AC servo motor has become a first choice of most fully automatic terminal crimping machine as system executive motors. The AC servo motors are well applied to the wire harness processing of fully automatic terminal crimping machine, which can improve processing efficiency and precision.

Frequency conversion technology is utilized to realize soft start and soft stop. The characteristics of speed up and speed down are utilized to increase the start and stop time of the motor. Take the motor of 1.5KW as an example, the motor employs the slowdown motor with a reduction ratio of 1:10. Through the reversing gear, the motor will change from the revolving movement into the straight line movement. Each revolving will realize one pushing action. When the incense stick goes through the discharging bucket, the stirring device for discharging will be driven with the chain drive organization while the motor is revolving. The material pushing jacket will be filled with incenses and then be extruded outside through pushing. In addition, As to the pressure(discharging quantity), the operator can adjust the revolving eccentric wheel to change the journey of the material pushing jacket and increase its discharging space, thus achieving the pressure change. Completing the whole process only needs about 0.4s, then one incense stick is finished. The VFD has been debugged for incense stick manufacturing, so as to reach the manufacturing requirements thoroughly.

Loading trolley, uncoiling machine, board swaging device, six-layer straightening machine, tracking shearing system, conveying and lifting work platform, double-layer pneumatic layout shelf, hydraulic system, electrical control system. The overall system adopts the VFD, PLC, touch screen, rotary encoder and other components to constitute the automatic control system of the production line. Under the premise of giving consideration to both horizontal shearing precision and manufacturing efficiency, through utilizing the high-speed counting function of the PLC and the speed regulating and controlling function of the VFD, so as to control the starting, operating, speed reducing, crawling and accurate stopping of the straightening roll and pressing roll effectively, thus realizing the high-efficient and automatic cutting to length of the metal plate.

In the entire manufacturing process of the concrete pile, molding on the centrifuge is the most vital step. This process includes: Cloth distribution, second level transition, compacting three stages. Different stages have different requirements to the revolving speed and time of the tubular pipe. In addition, the tubular pipes of different wall thickness and length will have different requirements to the revolving speed and time of the three stages. This requires the VFD to be able to regulate the working stage of the motor according to the different types of concrete piles. It will operate different speed and time at different stages to ensure the product quality of the concrete pile.

VFD and the display control HMI touchscreen is communicating through MODBUS, so as to realize the stopping, frequency setting and status monitoring and other functions of the VFD through the HMI touchscreen.

The wire-cut EDM is to utilize the metal linear tool electrode (or named as wire electrode) to process workpieces with the principle of impulsive discharge to erode the metals. High speed wire-cut EDM is applied in the processing of the metal pieces with high precision, complicated shape, especially the mould and so on.

Because the induction motor has incomparable advantages: Simple and solid structure, cheap price, and easy maintenance. So using the means of VFD dragging three-phase induction motor replaces the means of traditional speed regulating, can solve the problem of high failure rate of the tower crane fundamentally. Moreover, it has advanced technology and significant energy saving effect. It is the ideal transmission controlling device of the tower crane.

The overhead crane is a kind of hoisting machinery with quite extensive application in the industrial and mining enterprise. Its operating organism is constituted by three basically independent dragging systems, which are respectively the cart dragging system, dolly dragging system and hook dragging system. This article ATO will take the practical application of VFD for overhead crane improvement in thermal power plant as the example, illustrating the application and improvement scheme of VFD for the overhead crane comprehensively.

The VFD speed control system regards the network pressure as the control object. The pressure transmitter changes the pressure in the air storage tank into the electrical signal to send into the PID regulator inside the VFD, so as to compare with the pressure setting value. Then calculation will be made according to the set PID control mode based on the difference value. The control signal will be generated to control the output signal and inverter frequency of the VFD, thus adjusting the revolving speed of the induction motor, so as to maintain the practical pressure to be always as the setting pressure.

According to the manufacturing technology of the hydroextractor, the multi-speed functional control of the VFD can be used. The hydroextractor with VFD control system belongs to the approximate constant torque load with big inertia. Therefore, the system requirements can be reached by configuring braking unit and braking resistor on the basis of selecting the AC converter. The built-in braking unit of the30hp VFD and below can not only save space, but also save the cost.

This article ATO summarizes how to apply and debug the VFD for the circular knitting machine in one textile mill. ATO chooses the non-inductive vector VFD. It adopts current vector control, its precise control as well as the characteristics of low-frequency stability and large torque, realizing the functions of big starting torque, stable operation, quick stop and so on of the circular knitting machine.

The working principle of the automatic industrial washing machine is: under the unified deployment and management of the time schedule controller. The VFD controls the induction motor to carry out positive and negative revolving uninterruptedly, thus achieving the non-synchronous movement of the water and the clothes, so as to enable the water and the clothes to rub and knead, thus being cleaned.

For a long period, the chemical, cement, ceramic industries and so on normally adopt the ball mill to grind the raw materials. Usually, the decompression start-up mode is employed. The high starting current has great shocks to the equipment and power grid. Meanwhile, in working frequency, it is easily to over grid the materials. The required grinding circle is long, with low grinding efficiency and high unit product consumption. This promotes people to study and develop the ball mill system with smooth start, high grinding efficiency, high output and low consumption. This is exactly the VFD control system.

The turning rolls are the devices, which drive the cylinder-shaped (or cone-shaped) weldment to rotate with the help of the friction force between the weldment and the driving rollers. The self-aligning turning rolls are suitable for welding the round cylinder. It can regulate by itself according to the size of the cylinder. There are several specifications for the customer to choose. The self-aligning turning rolls include two groups of main and vice devices for one set, which means to four wheels for each device: self-aligning active turning rolls and self-aligning passive turning rolls. The wheel is fabricated in the inner iron core and outer rubber structure. Therefore, it is durable in use, free of any vibration. The operation of the active turning rolls is synchronously driven by the speed regulating motor through two worm gear reduction box. Thus, turing rulls can realize stepless speed variating by using ATO VFD.

Using VFD for speed regulating has many advantages. Many small power motors adopt single phase power supply. How to use VFD to regulate speed for single phase motors? ATO will provide the following methods.

The wire drawing machine is one of the main equipment of the metal wire processing as well as the cable and wire industry. It is mainly used to process the metal wires into the fine lines of various specifications. It usually constitutes the paying off, water cooling, winding up, winding displacement and other components. Its electric drive part is mainly realized by paying-off motor, winding-up motor and winding displacement motor. The wire drawing machine belongs to the constant-torque load. Its characteristics require that the VFD has a big start-up torque and can satisfy the full-load output in low speed. Meanwhile, it requires realizing the coordinated control of several motors in high precision percentage.