Abstract: This article mainly introduces the application of Chengzhiduo (VFDDRIVE) KE300A inverter in roving frame, briefly describes the characteristics of KE300A inverter and the specific requirements of roving frame for variable frequency drive and other relevant precautions.
Keywords: VFDDRIVE, variable frequency speed regulation, roving frame, KE300A
Ⅰ、Introduction
In the spinning process, the roving process plays a pivotal role. With the development of power electronics technology, PLC control, frequency conversion speed regulation, mechatronics and other technologies are used to replace the traditional mechanical structure, and the new suspended spindle roving frame is gradually replacing the support spindle roving frame, which improves the reliability of the whole spinning machine, improves the spinning quality and automatic operation. Especially in recent years, the wide application of frequency conversion speed regulation technology in roving frames has given roving frames a broader development prospect.
Ⅱ、Analysis of the application of frequency conversion technology in roving frames
According to the requirements of the spinning process, the roving frame will draw the cotton strips through the rollers, and then the yarn will be pulled out by the front rollers for twisting. Then, according to the requirements of winding and forming, the yarn will be wound on the bobbin. Since the yarn output speed of the front roller is constant, and the winding speed decreases in inverse proportion with the increase of the winding diameter, the traditional roving frame adopts a mechanical cone wheel speed change mechanism, and the belt moves on the upper and lower cone wheels to change the winding and lifting speeds to complete the roving winding and forming. One of the factors that affect the quality of the yarn in the roving production process is the details caused by starting, stopping and jogging.
1. Roving frame driven by a single motor
The main drive of the roving frame is driven by an AC asynchronous motor. In order to solve the problem of roving breakage caused by too fast speed increase when the motor starts, and the uneven roving strips when stopping, the traditional solution is to install reactors, time relays and electromagnetic clutches, collectively referred to as “anti-detail devices”. In addition, when the speed of the whole machine needs to be changed when spinning different varieties, the speed change is achieved by manually replacing the pulley.
The application of frequency conversion technology can well solve the problem of smooth start-up, eliminate the impact force when the machine starts, achieve stepless speed regulation, meet the production process requirements, and improve the quality of the yarn. When this technology is applied to the situation of different varieties of spinning, there is no need to change the teeth or pulleys. The change of the equipment process speed can be completed only through the frequency conversion setting, but the cone wheel speed change mechanism is still retained.
At present, the new roving frame and the transformation of the old machine adopt AC frequency conversion technology. This process problem has been solved. After testing the yarn quality of the FA413 roving frame before and after the transformation, the CV% of the roving evenness in the starting section decreased by 2-3%, and the coarse and fine details of the roving decreased by more than 90%.
2. Multi-motor driven roving machine
Due to the poor transmission speed stability of the mechanical bevel gear speed change mechanism, the operation is difficult, and it is easy to cause unstable roving quality. Therefore, many manufacturers have launched a new type of roving machine driven by multiple motors, which cancels the bevel gear speed change mechanism, forming mechanism, differential mechanism, swing mechanism and reversing mechanism, and also cancels the twist, lifting, winding, tension, forming angle and other conversion gears.
Four motors are used to drive the drafting rollers (generating drafting multiples), spindle wings (to make the roving wind onto the bobbin), bobbins (to make the roving twist) and dragon tendon lifting (to complete the winding shape). After using four motors for transmission, in addition to simplifying the mechanical structure and canceling the above-mentioned mechanism gears, it also reduces noise, increases the speed, reduces roving breakage, increases the output of a single machine (the main machine speed is increased by more than 30%), ensures the stability of roving quality, and changes the process simply and quickly.
However, the single-motor driven roving machines currently produced account for a large proportion of roving machines because of their low prices. Multi-motor driven roving frames have high speed and good performance, but due to their high prices, their sales account for only about 10%.
Ⅲ、KE300A inverter control solution for suspended spindle roving machine
1. Features of KE300A inverter
KE300A inverter has achieved high efficiency and low failure rate in the on-site suspended spindle roving machine, and has been unanimously recognized by customers. The advantages of the solution are summarized as follows:
(1) Smooth start and stop: slow acceleration, using the S curve acceleration and deceleration function, the motor starts and stops softly and smoothly. Reduce the impact wear and breakdown of the machine and protect the mechanical equipment.
(2) Convenient speed regulation: The inverter output frequency (speed) is adjusted by an external potentiometer, and there is no need to replace the machine’s speed wheel. Different spinning speeds can be set according to different spinning processes, that is, the spinning speed can be set higher for small yarns and appropriately lower for large yarns, so as to maximize the potential production capacity of the roving machine.
(3) It has the function of spindle wing positioning and parking.
(4) When changing the spinning variety, there is no need to replace the pulley. You only need to set the required speed through the inverter.
(5) The starting current is small, which reduces the capacity of the power supply equipment and has a significant power saving effect.
2. System control scheme
The main circuit wiring is very simple. Connect the three-phase power supply to the inverter input R, S, T terminals, and connect the inverter output U, V, W to the three-phase terminals of the corresponding motor. Pay attention to the terminal markings when wiring to avoid misconnection or reverse connection. Details are shown in the figure below:
The above diagrams only list the commonly used control wiring configurations. If you need to implement complex functions, please refer to the manual to modify the relevant wiring circuits and terminal function definitions. Since KE300A is a standard model, most parameters can be set according to factory parameters. When using it, users do not need to make too many complex settings, but only need to make simple parameter modifications according to the actual use site.
Ⅳ、 Use Effect
The application of (VFDDRIVE) KE300A inverter in roving frame actually solves the problems in roving production process. And the use of inverter control makes system control simpler, and the control system has multiple protections, making the system safer and more reliable. Ordinary roving frames such as FA421, FA423, TJFA458, etc. all use variable frequency speed regulation technology.
Ⅴ、Conclusion
The application of variable frequency speed regulation technology in roving frames is necessary, and it is also feasible to promote and apply it to traditional roving frame equipment. With the development of microelectronics technology and power electronics technology, the development of variable frequency speed regulation technology has also made great strides. Today, the adoption of variable frequency speed regulation technology has directly promoted the rapid development of the mechanical structure of roving frames, laying a solid foundation for the high speed, high quality and high intelligence of roving frames. It can be said that without the development of variable frequency speed regulation technology, there would be no high-quality roving frames today. The increasingly high level of mechatronics of roving frames will be the future development direction.
