Application of the most popular Lebang frequency c

2022-08-11
  • Detail

The application of Le Bang inverter in papermaking machinery

the papermaking industry plays an important role in the whole national economy. However, the speed control of papermaking machinery has always been a weak link in the papermaking industry. The paper-making process requires that the linear speed of each part be absolutely synchronized under their respective synchronous frequency points, so as to ensure that the paper is smooth, uniform in thickness, and not wrinkled or broken. The speed, stability and adjustability directly affect the output and quality of paper. For many years, the DC excitation speed regulation in the paper industry accounts for a large proportion of the new and old kinetic energy conversion proposed by Shandong Province. Although the DC excitation speed regulation motor has the advantages of good speed regulation performance and large starting torque, it has many disadvantages: high cost; Commutator and brush maintenance are difficult; Difficult to be used in harsh situations; The noise is too loud for operation

in today's energy shortage, most provinces across the country have begun to limit power, especially in East China. As a major power consumer, the paper industry is also particularly energy-saving. Therefore, the rapid development of motor frequency conversion and speed regulation technology provides this possibility, but for low-grade paper, in order to save costs, expensive imported equipment from abroad is not needed, Without using the upper computer and any other controller, the unique two-way analog synchronous control scheme of Lebang frequency converter can meet the requirements of the paper industry. Lebang frequency converter can take one analog quantity as the main machine for unified adjustment and the other for individual fine adjustment. The following is the application of Lebang frequency converter in a paper mill in Bazhou, which mainly produces Kraft face paper

(I): requirements of paper machine transmission on electrical control system

(1) the paper machine is a 2640 paper machine, which produces grams of kraft face paper. The structure of the paper machine is shown in Figure 1

the paper machine is composed of moving main pressing part, drying part, calendering part and coiling part. There are 6 transmission points in total, with a total power of 120kw. The power of each transmission point and the model of frequency converter are shown in the attached table

(2) process requirements of the paper machine for the transmission system

in order to produce products with high quality standards, the paper machine has the following process requirements for the transmission system:

a) the working speed of the paper machine should have a large adjustment range: in order to make the paper machine have strong adaptability to the same metal products and raw materials (such as beating degree, slurry ratio and type, quantitative, paper type, etc.), the paper machine transmission can adjust the speed evenly in a large range, Speed regulation range d=1:8

b) the vehicle speed should have a high stability margin: the total vehicle speed should increase and decrease smoothly. The paper machine speed often fluctuates due to the changes of power supply voltage, frequency and paper machine load. In order to stabilize the quantity and quality of paper and reduce the breakage of paper, the paper machine is required to be stable

c) the speed ratio between sections is adjustable and stable: when the paper web is in the section and the pressing section, its longitudinal elongation and transverse contraction, while when drying the trunk, it shrinks in both directions. Therefore, the linear speed of each part of the paper machine is slightly different. The maximum fluctuation value of the speed ratio of each section of the paper machine is related to the factors such as the proportion of slurry, ration, speed, production technology, and the tension of the unsupported leading section of the paper web between the sections. Therefore, there should be an appropriate speed difference between adjacent sections of the paper machine to form a good paper sheet. The speed of each part of the paper machine must be adjustable within ±%. At the same time, in order to produce high-quality paper and reduce the breakage rate, it is necessary to maintain the stability of the speed ratio between segments. When the speed of a certain segment changes due to load change or other interference, it should be able to adjust in time so that the change of speed ratio of the segment does not exceed the specified range

d) the paper tightening function of the research and development entity with the function of slightly increasing and decreasing the speed at a single branch point, and strengthening the technical support and guarantee for major national strategic tasks and key projects during the paper introduction operation. And in these divisions, it should have single action and linkage functions. It can start and stop at the same time. Necessary display, such as line speed, current, operation signal, fault signal, etc

e) separate fine adjustment of each circuit in order to overhaul and clean the operating conditions of each segment, each segment should be fine adjusted separately. At the same time, the speed of each segment in the synchronous speed should be adjusted at different values, so as to achieve the future synchronous control

f) the paper machine transmission is a constant torque load. The frequency converter with constant torque control performance and high resolution should be selected to meet the needs of the normal operation of the paper machine control system

(II): composition of electrical control system

(1) composition of system hardware

lb60g high-performance general frequency converter is adopted as frequency converter, and asynchronous motor is adopted as motor. The hardware composition of the system is shown in Figure 2

(2) control of multi motor drive drafting synchronization

in papermaking equipment, it is based on determining the relative speed synchronization of each part. There is a main given signal, and the goal of synchronization control is to ensure that the proportion of synchronization can be maintained in the process of acceleration, constant speed or deceleration

2.1 synchronous control of analog quantity and fine-tuning of each part of analog quantity

when a complete machine is required to be set at a master speed, all units work synchronously and harmoniously; A synchronous controller can be configured, which can set the transmission speed of each unit separately to realize the synchronous work of each unit at a certain proportional speed. With lepang frequency converter, one VCI analog channel in the two analog signals of lepang frequency converter can be used as the main setting to be responsible for synchronous control, while the other CCI is responsible for fine-tuning of each part. See Figure 3

for the specific peripheral circuit and system. In the figure, R is a synchronous adjustable button, and R1-R6 is a separate adjustable button. The specific settings are as follows:

1 Enter B-00 and set it to 5 combination given 2

2. Enter B-02 and set it to 1 external terminal operation control

3. Enter B-12 and b-13 and adjust the acceleration and deceleration time according to the actual situation

4. Enter P-13 set to 0, V control

5. Enter P-14 set to 0, V control

6. Enter P-16 and set it to 1 to select CCI as the auxiliary channel selection

(III): conclusion

papermaking machinery can choose different synchronous control and distribution adjustable methods according to the type of paper produced when all switches are turned off. This scheme is only applied to the production of grams of kraft face paper. It has been successfully applied to the reconstruction of many papermaking equipment and achieved the expected results

Copyright © 2011 JIN SHI