Crane electric PLC frequency converter control system
Time：2015-06-18 03:06
Read：10994
Source：Internet
summary
With the rapid development of communication technology and control technology, computer monitoring system is widely used in hydropower stations, especially unattended and few people are on duty; At the same time this control mode is put forward, hydropower stations, water conservancy projects and other projects put forward new requirements for the automation level of gate monitoring and management.
According to the market demand, the new generation gate control system developed by our company takes the programmable controller as the control core, adopts the industrial Ethernet technology, and configures a high-performance upper computer, which makes the system structure simple and clear, greatly improves the reliability and availability of the system, reduces the intensity of commissioning, operation and maintenance, and becomes an indispensable equipment for the hydropower station with no one on duty and few people on duty.
The system has simple structure and convenient operation. The operator only needs to input the height of the gate to be adjusted in the upper computer control screen and confirm, and the gate monitoring system can automatically complete the start and stop of the gate as required. High control accuracy and fast response speed.
Electrical equipment transformation
The transformation of electrical equipment mainly includes the crane control cabinet, electrical control elements, cables, automation elements (encoders, load sensors, travel limiters, etc.), linkage console, etc.
Control cabinet: stainless steel or carbon steel plastic spraying material can be used according to customer requirements. The recommended material thickness is 1.5mm for stainless steel and 2mm for carbon steel. The size of the control cabinet can be customized according to the site conditions;
Electrical control components: mainly including circuit breakers, contactors, relays, etc. imported brands such as Siemens and Schneider are mainly used, and can also be changed to domestic well-known brands according to customer requirements;
Cable: including power cable and communication cable. It is recommended to select marine cable (CEFR) for power cable and shielded cable (RVVP) for communication cable; All cables are made of domestic well-known brands;
Linkage operation platform: provide reliable operation platform for crane operators. Each console is equipped with one seat that can be adjusted up and down, front and back.
Transformation of frequency conversion control
Although the traditional speed regulation system realizes the speed regulation function through the series resistance of the rotor (it is also graded), it can not change the synchronous speed of the motor, resulting in very soft mechanical characteristics of the transmission system and poor speed stability and speed regulation accuracy. Moreover, due to the change of load, the flatness of track and the dispersion of motor parameters, the girder torsion and the vibration of electric control equipment on the traveling crane are large. It not only deteriorates the working environment of operators, leads to operational errors, but also reduces the stability, reliability and service life of the whole equipment.
The crane has the following characteristics after using frequency converter for speed regulation:
1) The speed can be continuously controlled within the whole speed regulation range, with good open and closed-loop characteristics. The speed regulation ratio can reach 1:100, and the speed regulation accuracy is ± 1%.
2) The speed regulation is stable, which effectively prevents swing hook and has excellent dynamic response to sudden load change.
3) Stepless speed regulation, high transmission efficiency of 97%, nearly 1 power factor value.
4) Full torque output at zero speed, even if the brake is loose or fails, there will be no sliding of heavy objects to ensure the safety and reliability of the system.
5) It can run at low speed for a long time, so that the speed regulation accuracy can easily enter the millimeter level positioning function.
6) Save electric energy, and the power saving rate reaches 20% - 60%.
7) Mechanical damage is small.
8) The maintenance rate is low, and the circuit design of the frequency conversion electrical system is relatively simple. Since a number of high-power AC contactors, slip ring carbon brush holders, series resistors and other electrical components for controlling forward and reverse rotation and speed regulation are saved, the electrical control circuit is greatly simplified, and the logic circuit completed by the traditional complex circuit is replaced by the various functions of the frequency converter itself.
Frequency converter we recommend ABB frequency converter or Schneider Electric ATV series frequency converter.
Automatic control transformation
PLC is added as the core control element in the system, and a 10 Inch Touch screen is provided as the operation and display terminal. PLC is responsible for collecting the sampling values of all automatic elements, the signals of each limit operation position, the start and stop state signals of the motor, the operation commands, etc. The use of distributed I / O modules can effectively reduce the use of control cables.
Its advantages are as follows:
1) The PLC has the locking start function. Before starting the equipment, the driver must switch the master controller to the zero position and the threshold switch of the entrance and exit door in place before connecting the main power supply. There is an equipment status indicator screen on the operation master switch to display the current status of the equipment and various fault information.
2) The main and auxiliary hooks are protected by wire rope lifting limit, weight limit and overweight limit, and the crane and trolley are protected by travel switch. The protection action of each equipment only affects the action of the equipment itself.
3) All fault signals of electrical equipment are connected to PLC, and any fault of electrical equipment will only affect the action of the unit.
4) The lifting hook is interlocked with the forward and backward movement of the trolley and the left and right movement of the crane.
5) The speed of the main hook, auxiliary hook, crane and trolley can be switched by the gear of the master switch to achieve smooth switching.
6) It is prohibited for the driver to position the cart and trolley by reversing the cart.
The system structure is as follows:
With the rapid development of communication technology and control technology, computer monitoring system is widely used in hydropower stations, especially unattended and few people are on duty; At the same time this control mode is put forward, hydropower stations, water conservancy projects and other projects put forward new requirements for the automation level of gate monitoring and management.
According to the market demand, the new generation gate control system developed by our company takes the programmable controller as the control core, adopts the industrial Ethernet technology, and configures a high-performance upper computer, which makes the system structure simple and clear, greatly improves the reliability and availability of the system, reduces the intensity of commissioning, operation and maintenance, and becomes an indispensable equipment for the hydropower station with no one on duty and few people on duty.
The system has simple structure and convenient operation. The operator only needs to input the height of the gate to be adjusted in the upper computer control screen and confirm, and the gate monitoring system can automatically complete the start and stop of the gate as required. High control accuracy and fast response speed.
Electrical equipment transformation
The transformation of electrical equipment mainly includes the crane control cabinet, electrical control elements, cables, automation elements (encoders, load sensors, travel limiters, etc.), linkage console, etc.Control cabinet: stainless steel or carbon steel plastic spraying material can be used according to customer requirements. The recommended material thickness is 1.5mm for stainless steel and 2mm for carbon steel. The size of the control cabinet can be customized according to the site conditions;
Electrical control components: mainly including circuit breakers, contactors, relays, etc. imported brands such as Siemens and Schneider are mainly used, and can also be changed to domestic well-known brands according to customer requirements;
Cable: including power cable and communication cable. It is recommended to select marine cable (CEFR) for power cable and shielded cable (RVVP) for communication cable; All cables are made of domestic well-known brands;
Linkage operation platform: provide reliable operation platform for crane operators. Each console is equipped with one seat that can be adjusted up and down, front and back.
Transformation of frequency conversion control
Although the traditional speed regulation system realizes the speed regulation function through the series resistance of the rotor (it is also graded), it can not change the synchronous speed of the motor, resulting in very soft mechanical characteristics of the transmission system and poor speed stability and speed regulation accuracy. Moreover, due to the change of load, the flatness of track and the dispersion of motor parameters, the girder torsion and the vibration of electric control equipment on the traveling crane are large. It not only deteriorates the working environment of operators, leads to operational errors, but also reduces the stability, reliability and service life of the whole equipment.
The crane has the following characteristics after using frequency converter for speed regulation:
1) The speed can be continuously controlled within the whole speed regulation range, with good open and closed-loop characteristics. The speed regulation ratio can reach 1:100, and the speed regulation accuracy is ± 1%.
2) The speed regulation is stable, which effectively prevents swing hook and has excellent dynamic response to sudden load change.
3) Stepless speed regulation, high transmission efficiency of 97%, nearly 1 power factor value.
4) Full torque output at zero speed, even if the brake is loose or fails, there will be no sliding of heavy objects to ensure the safety and reliability of the system.
5) It can run at low speed for a long time, so that the speed regulation accuracy can easily enter the millimeter level positioning function.
6) Save electric energy, and the power saving rate reaches 20% - 60%.
7) Mechanical damage is small.
8) The maintenance rate is low, and the circuit design of the frequency conversion electrical system is relatively simple. Since a number of high-power AC contactors, slip ring carbon brush holders, series resistors and other electrical components for controlling forward and reverse rotation and speed regulation are saved, the electrical control circuit is greatly simplified, and the logic circuit completed by the traditional complex circuit is replaced by the various functions of the frequency converter itself.
Frequency converter we recommend ABB frequency converter or Schneider Electric ATV series frequency converter.
Automatic control transformation
PLC is added as the core control element in the system, and a 10 Inch Touch screen is provided as the operation and display terminal. PLC is responsible for collecting the sampling values of all automatic elements, the signals of each limit operation position, the start and stop state signals of the motor, the operation commands, etc. The use of distributed I / O modules can effectively reduce the use of control cables.
Its advantages are as follows:
1) The PLC has the locking start function. Before starting the equipment, the driver must switch the master controller to the zero position and the threshold switch of the entrance and exit door in place before connecting the main power supply. There is an equipment status indicator screen on the operation master switch to display the current status of the equipment and various fault information.
2) The main and auxiliary hooks are protected by wire rope lifting limit, weight limit and overweight limit, and the crane and trolley are protected by travel switch. The protection action of each equipment only affects the action of the equipment itself.
3) All fault signals of electrical equipment are connected to PLC, and any fault of electrical equipment will only affect the action of the unit.
4) The lifting hook is interlocked with the forward and backward movement of the trolley and the left and right movement of the crane.
5) The speed of the main hook, auxiliary hook, crane and trolley can be switched by the gear of the master switch to achieve smooth switching.
6) It is prohibited for the driver to position the cart and trolley by reversing the cart.
The system structure is as follows:
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