Main drive system of the hottest paper machine coa

2022-07-31
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The main drive system of paper machine and coater

as "this is a rigid demand market with a consumption of 1.5 million tons/year", when the paper passes through various parts of the paper machine, its shape can be divided into different sizes, the composition of materials is various, and its state is constantly changing. The electric drive control of the paper machine is to use different control methods according to the characteristics of different paper states to ensure the quality of paper and the reliable, stable and continuous high-speed operation of the paper machine; The operation method is scientific, simple and intuitive. At the same time, it provides an effective way for production and equipment management

the main drive control system of Huazhang paper machine adopts microprocessor-based automatic adjustment of speed loop, torque loop and tension loop. The acceleration and deceleration set by the program will be a very slow start time and maximum/minimum speed value. The inverter has the motor model identification function. Once a fault occurs, the output pulse will be blocked immediately

1. Wet end drive control

in order to ensure the paper compounding effect, the speed closed-loop control is adopted for the drive roller of the decision part; Load distribution is adopted between the transmission points on the same and between the press rollers in contact with each other

2. Cadre transmission control

since the paper tension of cadres has been established, the control of cadres aims at the tension. Torque/tension control is adopted for the transmission points in the areas where the tension is easy to change, while speed closed-loop control is adopted for the transmission points in the areas where the tension is not easy to change

3, speed chain

speed closed-loop control, load distribution control, torque/tension control and relaxation constitute an open tree speed chain. It is the core of the whole transmission control system, and various control modes are harmoniously unified here

4. Winder control

in order to ensure the quality of the paper roll, the winder adopts constant tension control. At the same time, in order to ensure that the paper roll has a certain hardness in the radial direction, it is tight inside and loose outside, and the pressing area of the winder is controlled. In addition, according to the actual needs of production, the sizing and length control of the winder can be realized

5. System interlocking

in order to ensure the continuous and normal operation of the equipment, the operation of some paper machine auxiliary equipment is coordinated by the controller of the PLC system. The interlocking provided by the system includes: safety interlocking, process interlocking, start interlocking, shutdown interlocking, paper break interlocking and fault interlocking. To realize the development strategy of one body and two wings

6. System protection

in order to ensure equipment and personal safety, the transmission control system provided by Huazhang company has the following protection functions: phase sequence monitoring, phase loss monitoring, undervoltage monitoring, overvoltage monitoring, instantaneous overcurrent protection, long-term overcurrent protection, encoder signal loss alarm and protection, overfrequency, overspeed alarm and protection, grounding fault alarm, communication fault alarm

7. Communication with other systems

as the communication network technology is adopted in the paper machine drive control system, the data and system chain information of each drive division of the paper machine can be directly transmitted to the information layer network, namely Ethernet, through the communication network. The Ethernet adopts the public communication protocol (Ethernet IP), so it can transmit data to other systems (such as MCS, DCS and QCS systems)

the paper machine main drive control system provided by Huazhang company can also output the following analog signals for instruments and automatic control systems to collect:

bottom speed signal: 4-20mA or coded pulse signal (corresponding to the system speed of 0-350 M/min)

linear speed signal of coiling cylinder: 4-20mA or coded pulse signal (corresponding to the system speed of 0-350 M/min)

8 Dynamic control system accuracy

static control accuracy

--------- speed control accuracy relative to rated speed ≤ 0.01%

--------- control accuracy of relative speed difference between two adjacent sub groups ≤ 0.01%

dynamic control accuracy

--------- interference (such as torque change) The short-time speed deviation during the acceleration and braking process is ≤ 0.05%

--------- the short-time tension control accuracy during the constant speed period is ≤ 1%

--------- the tension control accuracy from the constant speed to the acceleration or braking state is ≤ 4%

9. The auxiliary drive control system

the auxiliary drive constant speed motor has the function of short-circuit protection, overload protection and manual circuit breaking. For the auxiliary drive motor with the tensioner on the bottom floor, a button station is set on the bottom floor of the workshop to facilitate the operation of tightening and loosening the blanket. An LED digital display clock with a word height of no less than 50mm is configured on the unit and the coiling console. The clock operates independently in a 24-hour system

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