In recent years, with the continuous improvement of textile machinery and electromechanical integration technology and the characteristics of the textile industry, the requirements for textiles have been continuously updated. For many reasons, higher demands have been placed on textile equipment. In the fierce market competition in the past 10 years, domestic and foreign textile machinery manufacturers adopt PLC control, frequency control, electromechanical integration, etc. to replace the traditional mechanical structure with electronic technology, improve the reliability and spinning of the whole textile machine. The degree of quality and automation, the expansion of the variety of adaptability, and ease of use. All textile manufacturers also invest in retrofitting old equipment. AC frequency conversion speed control technology is used more technology, in most newly developed textile machinery products almost without exception the frequency converter.
First, the characteristics of AC frequency control
1, reduce power consumption and reduce costs
The textile factory can not do without the air conditioning equipment. When the air conditioner motor is controlled by the frequency converter, the fan can be steplessly adjusted according to the environmental conditions of the workshop, which enlarges the adjustment range. Most fans work in 50-80% efficiency. , This has a good energy-saving effect, up to about 60%; in the water pump control application can adjust the water pump speed according to the amount of water, to achieve energy conservation and also achieved near constant pressure water supply. The above two main energy-consuming equipments adopt frequency conversion speed regulation to reduce power consumption and greatly save power consumption. Pu Chuan Science and Technology Company has tested the use of one of its customers. In the year, 12 sets of air conditioners can save more than 240,000 yuan, and the average power consumption of air conditioners has dropped by 6.7 percentage points.
2. Simplified organization and improved performance
Through the PLC programmable controller or industrial computer control, and then through the inverter to achieve synchronous operation of multiple motors. Controlling the motion of each mechanism according to the production process curve simplifies the mechanism. For example, the roving machine utilizes variable frequency speed control to remove the cone-wheel speed change mechanism, thereby overcoming the problem of inconsistent speed change of the conical wheel speed change belt.
For the spinning frame, the use of a frequency converter removes the forming cams in the forming mechanism, thereby overcoming the phenomenon of pauses on the peach bottom and impact on the peach top due to the forming cam. Makes the fine roll shape good. In order to facilitate the next process of high-speed unwinding. At the same time, the inverter is used to control the speed change of the thirty-nine main motor to control the number of revolutions of the spindle, so that the spinning speed changes when the spun yarn is in large, medium and small yarns, and the yarn breakage rate is reduced.
AC frequency conversion speed control technology has been widely used in new domestic cotton textile equipment. There is very little promotion and application of cotton textile equipment currently in service. Most of the equipment used by cotton textile companies are equipment manufactured in the 1970s and 1980s. These equipments can still be used for a considerable period of time in terms of mechanical conditions. All recent updates are impossible, but some of them are undergoing electric drive transformation. Completely feasible.
Take the example of the implementation of frequency conversion technology in the two processes of carding and roving. A cotton spinning enterprise with a production capacity of 50,000 spindles, equipped with about 80 sets of carding processes, and about 20 sets of roving processes. If the carding machine is a 186D or A186F type, the conversion fee A is about 280,000 yuan, but the electromagnetic clutch, 2 contactors, intermediate relays and rectifiers etc. are cancelled during the conversion of frequency conversion technology. These electrical materials save nearly 1,000 yuan. It effectively protects the Doffer motor and the doffer drive train, reduces the failure rate, and reduces maintenance costs. This saves material costs of 1,200 yuan per unit, and 80 units can save 96,000 yuan. Through simple calculations, the payback period is 4.35 years, and the total investment return rate is 22.97%.
Second, the application of AC frequency conversion technology
Inverter-controlled textile machinery AC motors involved are mainly divided into two categories: One is the commonly used Y series of AC asynchronous motors, this motor is mainly used in speed control accuracy is not high, the speed range is not large on the textile machine ; And the other is the AC induction motor for frequency control; mainly used for speed control accuracy, speed range of the machine.
The following describes the different series of frequency converters applied to textile machinery.
1. PI168 series inverter: The open-loop control of asynchronous motor with inverter is called V/F form. This method is simple and reliable. However, the speed range is within the range of 10:1, the speed accuracy is lower by 2% to 5%, and the low speed performance is not ideal. Therefore, it is mostly used in knitting machines or textile machines that require less.
2. PI7000 series high performance frequency converter: It adopts speed sensorless vector control inverter. It has excellent low speed characteristics. The circuit structure is simple and highly reliable. At the same time also has a good addition and subtraction characteristics, torque characteristics and current limiting characteristics. Speed ​​accuracy can reach 0.5% to 1.0%. The speed range is within 20:1. Suitable for speed and other printing and dyeing machinery.
3, PI7000S frequency converter uses vector frequency conversion control asynchronous motor with speed feedback, closed-loop frequency control, speed range up to 100:1. High-frequency response, high precision, and intelligence can be achieved. It is applicable to slitting warping machines, sizing machines, heat setting machines, chemical fiber filament spinning machines, etc., which require higher speed and constant tension and constant line speed.
Third, the application of frequency converter in textile machinery
Inverters are used in spinning machines, and it can be said that almost every machine in the process is used. Including open cleaners, carding machines, slivers, combers, drawframes, roving machines, spinning machines, and Lobster machines. For weaving machines, there are sizing machines and warping machines. In addition, inverters are also widely used in knitting machines, non-woven fabrics, chemical fiber machines, and printing and dyeing machines.
1, roving machine
The bobbin winding of the roving frame and the rotation speed of the front roller are likely to be different during the start and stop, resulting in too much and too small tension of the roving, so that it is easy to form rough details of the roving, in order to reduce the occurrence of coarse details in the roving frame. Transmission design reactor, time relay plus electromagnetic clutch, collectively referred to as anti-detail device. The role of the reactor is to make the main motor in a three-phase unbalanced state when the roving frame is started, thereby reducing the starting torque of the motor and achieving the purpose of soft start. The time relay and the electromagnetic clutch are the iron gun and the bobbin when the roving frame is stopped. The winding phase is disengaged, the bobbin stops winding, and the front roller still continues to output the roving with inertia, and the roving between the roller and the flyer has a certain degree of slack so as to prevent excessive tension when the roving is driven again.
This kind of anti-detail device has serious defects in actual use. One is that the reactor string is in one phase of the three-phase circuit. The three-phase unbalanced principle is used to reduce the starting torque of the motor. After the roving machine is started, the reactor is shorted by the time relay to restore the three-phase balance of the motor. Put into normal operation. If there is a problem with the time relay, the motor will be in a three-phase unbalanced operation for a long time, causing the motor to overheat and burn out. The second is that the clutching time of the electromagnetic clutch for parking is achieved through the adjustment of the two time relays, which makes it more difficult to grasp the degree of slackness of rovings. In addition, the malfunction of the electromagnetic clutch is also high; therefore, such anti-detail devices are There is very little that can be maintained in actual production, and the problem of preventing rovings from being detailed has not been well resolved. At present, new types of roving machines and old machines are transformed using AC frequency conversion technology. Solve this process problem. After testing the yarn quality of the FA491 roving machine before and after its transformation, the dry CV% of the roving bar at the start-up segment decreased by 2-3%, and the coarse yarn detail decreased by more than 90%.
FA491 high-speed suspended roving machine is a new type of roving machine developed in recent years in China. The industrial machine, PLC and inverter were used to control the four motors. The rotor, roller, pipe and dragons were turned up and down respectively, and the cone-wheel transmission and molding device were eliminated, simplifying the mechanism. High efficiency, high reliability, low noise, easy operation and maintenance. Good process adaptability and reduced breakage. The highest speed is up to 1500rpm, enabling new technologies such as man-machine dialogue, parking and automatic positioning. It is a high level roving machine.
2, sizing machine
The application of variable frequency speed regulation on the sizing machine reduces the mechanical structure and the motor. In the G142 series sizing old machine transformation using AC frequency control, to reduce the original design of the first set of mechanical continuously variable transmission, while eliminating the need for a servo motor and a slow motor. In satisfying the sizing process, the vehicle speed is converted from slow speed, main engine plus acceleration and deceleration speed into uninterrupted stepless speed regulation of the vehicle speed from the start-up process speed, which adjusts the pressure for the vehicle speed change and provides conditions for sizing sizing rate equalization.
The GA308 sizing machine is an AC distribution drive. The sizing tank, the sizing tank and the drying cylinder are AC frequency conversion motor drives, and the weaving shaft and the tow roller are individually driven by the AC servo frequency conversion motor. A total of five transducers, two servo controllers, and sensors such as pressure, temperature, and moisture regain were used. It is controlled by IPC and PLC. Constitutes a distributed control system. Among them, the PLC is used to control the operation of the whole machine and the parameters such as the moisture regain rate, the temperature of the drying room and the slurry tank, and the pressure of the squeezing roller. The whole machine is controlled by the IPC. This machine has high control precision, stable performance and low failure rate. It is a high-quality, high-level equipment.
3, cotton textile equipment applications
In the spinning process, the electrical driving of the processing equipment is required to be stable, and the jogging, starting, and lifting speeds should all be smoothly achieved. In this way, the draft of the fiber can be evenly distributed, and the weight non-uniformity and the dry CV value can be reduced. In the transmission system of cotton spinning equipment, belts and gears are all responsible. Due to the hardness of motor starting, belt slipping and gear impact are inevitable during the jogging and starting. In mechanical transmission trains, the more gears there are, the greater the chance of damage to the gears. Applying AC inverter technology can solve the problem of smooth startup, eliminate the impact of mechanical startup, achieve stepless speed regulation, and satisfy the production process. Requirements, improve the quality of yarn. When this technology is used to change yarn types, it is not necessary to change the teeth or the pulley. The change of the process speed of the equipment can be accomplished simply by setting the frequency conversion.
In the design of the old carding machine, due to the limitations of the technical conditions, equipment manufacturing costs, market needs and other factors, there are inevitably some defects. For example, the electromagnetic clutch in the drive system of the A186D carding machine is often caused to stop because of the high failure rate. From time to time, a fire alarm occurs, causing a certain loss to the production efficiency and product quality. It requires a lot of manpower and material resources to maintain and maintain. Some companies have used inertial wheel electromagnetic clutches. In this way, thin strips are produced in the process of slow turn of Doffer. In severe cases, there is a broken edge, and the phenomenon of broken cotton nets affects the quality of the sliver. In order to avoid this phenomenon, some companies use improper methods of operation to make up for the above-mentioned equipment defects, but it is also undesirable to create a large number of scraps.
The process of improving the operating state of the carding machine. A186D card machine In order to make Doffer achieve up and down speed smooth, in the mechanical transmission design two-speed motor, inertia wheel, electromagnetic clutch, electrical and mechanical means to achieve. In the design of A186E, A186F and FA201 carding machines, the star-triangle conversion control of the motor was added, which further improved the ascent and descent slopes. FA201B, FA212 carding machine adopts the AC frequency conversion speed regulation, thus realizes the random adjustment of the doffer's uphill slope, and any variable function of the doffer's process speed. Provide a good example for the transformation of old machines.
The A186D old machine is undergoing AC frequency conversion and speed control transformation, which will not only improve equipment performance, but also reduce downtime. It can also increase production efficiency and sliver quality.
Conclusion
The application of AC frequency conversion speed regulation technology in textile equipment is necessary. It is also feasible to popularize and apply traditional textile equipment.
The progress of the internationalization of China's textile industry is accelerating. However, compared with the international advanced level, there is still a big gap. In order to narrow the gap, we should continue to improve the level of mechanical and electrical integration of textile machinery, the AC frequency conversion technology is better applied to the control of textile machinery, we must continue Developed high-quality, high-level inverters and AC servo motor controllers with China's independent intellectual property rights, actively promoted intelligent technologies, field bus technologies, and realized network control, and realized human-machine dialogues through digital displays and touch screens.