Beijing ABB Electric Transmission System Co., Ltd. was established in 1994. It is jointly funded by ABB and Beijing Jingyi Holdings Co., Ltd. It is part of the ABB Group Automation Products Division. It is the first batch of ABB Group's business companies in China. Transmission products, production and sales of transmission products for motor speed control from 0.12kW to 27,000kW, according to data from ARC research institutions, in today's Asia Pacific AC drive market, ABB electric drive products have taken the market share Rate, widely used in power, metallurgy, textile, petrochemical, cement, paper and other industries.
Since its establishment in 1994, ABB Drive has been committed to the local production of ABB electric drive products. At present, ACS500, ACV700 & DC drive products, ACS400, ACS600, ACS550, and ACS800 have all been assembled and produced locally.
1. Working principle of the inverter
Variable frequency drive (VFD), as the core component of variable frequency control cabinet, is an electric power control device that applies variable frequency technology and microelectronics technology to change the frequency of the working power of the motor to control the AC motor. By changing the frequency of the power supply, the purpose of changing the power supply voltage is provided, and the required power supply voltage is provided according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. In addition, the inverter also has complete protection functions and excellent starting performance. The speed regulation process is simple, smooth, high degree of automation, safe and reliable. With the continuous improvement of the degree of industrial automation, the inverter has been more and more widely used.
2. The main advantages of the inverter
A. Soft start function: When the motor starts at power frequency, the starting current is about 7-8 times of the rated current of the motor. This current greatly exceeds the current of the motor windings and generates heat. Frequent start is easy to reduce the service life of the motor. The inverter can fully reduce the starting current, reduce the maintenance cost of the motor, and extend the service life of the motor.
B. Reduce power line voltage fluctuations. When the large-capacity motor starts at power frequency, the current will increase sharply, and the grid voltage will also fluctuate greatly, which will cause the voltage to drop, which will cause tripping or abnormal operation of other equipment. After using variable frequency speed regulation, it can start from zero frequency and zero voltage. Minimize voltage fluctuations.
C. Flexible speed regulation method can meet the technological process to the greatest extent.
D. The energy saving effect is obvious. The energy saving effect of the inverter is most obviously reflected in the application of fans and pumps. It can be known from fluid mechanics that the flow rate Q is proportional to the first power of the rotation speed N, the pressure H is proportional to the square of the rotation speed N, and the power P is proportional to the cube of the rotation speed N, P (power) = Q (flow) ¡Á H (pressure) If the efficiency of the pump is constant, when the adjustment of the flow rate is required, the speed N can be proportionally decreased, and the shaft output power P at this time is reduced. That is, the power consumption of the water pump motor is approximately proportional to the speed. When the required flow rate Q decreases, the output frequency of the inverter can be adjusted to reduce the motor speed n proportionally. At this time, the power P of the motor will be greatly reduced according to the cubic relationship, which can save energy by 40% to 50% compared with adjusting the baffle and valve, so as to achieve the purpose of saving power.
Second, the characteristics of frequency conversion control cabinet
1. Use inverters from well-known brands at home and abroad. According to customer needs, Nanjing Kangzhuo Environmental Technology Co., Ltd. uses ABB inverters as the core components of our company's inverter control cabinets to design and manufacture Kangzhuo's own inverter control cabinets.
2. Well-designed. From design to selection of components and complete production of our variable frequency control cabinets, each link is strictly in accordance with the national 3C quality certification, strict control, high quality and strict requirements for each process of design, procurement, production, inspection, and delivery Make strict quality management and tracking. Before designing, our design engineers according to the requirements of the customer, the site environment (temperature, humidity, electromagnetic radiation level, explosion-proof level, etc.); the specific parameters of the motor such as origin, rated current, rated voltage, number of phases, motor load type, Working system; motor starting method; the number of frequency converter cabinets to drive the motor, control cabinet control methods, such as manual / automatic, local / remote; power quality requirements for power supply applications, lightning protection, surge, electromagnetic radiation, in-depth understanding of the drive The mechanical characteristics of the machine, and then comprehensively consider which brand of inverter of that series is used as the core device of the electric drag. After comprehensive consideration, design the electrical schematic diagram. In the design, do some suppression measures for possible interference, For example, installing reactors for incoming and outgoing lines, isolating transformers, using shielded cables for sensors, and grounding the inverters separately, partly install lightning protection, surge protection measures, and other protective measures according to the installation location of the control cabinet.
After the design of the electrical control principle is completed, we will carry out targeted electrical process design, including electrical wiring, layout of component installation positions, and sheet metal design of the electrical cabinet. Consider whether to install according to the temperature and humidity of the environment Cooling fan, corresponding dehumidifier. Also, whether there is explosive gas, and other comprehensive selection of cabinet material, protection level and so on.
In the process equipment, strictly follow the design and the country's corresponding wiring installation specifications. Strive to achieve beautiful and generous wiring, clear layers, firm and reliable wiring, and good contact. The markings are complete, clear and firm. The panel is neat and the components are arranged evenly and beautifully.
4. Strict inspection.
The inspection adopts strict standards and strictly follows the design and inspection process. Once problems are found, they are tracked down until the problem is found, and sufficient tests are performed during inspection to ensure zero errors.
5, affordable. Thoughtful and timely after-sales service and timely delivery.
3. The main components of the frequency conversion control cabinet are selected. Our company's frequency conversion control cabinet is selected from manufacturers with good brand reputation and quality at home and abroad. For example, the contactor is mainly selected from Chint and Schneider. The circuit breaker is mainly selected from Schneider and Chint. The buttons are also selected from Schneider and Chint, and the intermediate relays are also selected from Chint, Schneider, Omron and other outstanding quality brands. At the same time, for the pumps, we also use the self-developed Kangzhu brand comprehensive protection, which has been independently proven by our company and has proven quality and reliability. The converter and pump controller work with the frequency converter. PLC uses Siemens brand. Good design and reliable components are an important guarantee to ensure the quality of our control cabinet. We generally have the function of switching between power frequency and frequency conversion. When there is a problem with the inverter, it can be switched to power frequency operation, which improves the flexibility of accident response. The autotransformer uses Zhengtai products and chooses different configurations according to different customer requirements. If customers pay attention to quality and stability, there is a slight margin for engineering cost. Our components are generally Schneider, and the inverter is ABB, Schneider or Siemens. ; If the customer pursues cost-effectiveness, we will configure Chint and Orient inverters to balance the performance and price relationship for the customer.
V. Applicable occasions of Nanjing Kangzhuo frequency conversion control cabinet Our frequency conversion control cabinet is mainly for fans and pumps. It mainly uses PLC technology and PID algorithm to intelligently adjust the operating frequency of the inverter to meet the actual production needs.
Main application areas:
1. Widely used in urban and rural water supply systems.
2. Closed-loop constant-pressure water supply for high-rise buildings, domestic and firefighting water, and industrial water.
3. Automatic control of boiler make-up water pump and thermal heating circulation pump.
4. Farmland irrigation and fountain control.
5, air-conditioning control and cold water circulation control.
6. Flow control and secondary pressure control in water plants, pumping stations, and petrochemical industries.
7. Various energy-saving transformations and various production lines with high requirements on speed regulation performance.
8. Various occasions requiring constant pressure gas supply.
Fourth, Nanjing Kang Zhuo inverter control cabinet installation and commissioning installation:
1. First confirm that there is no explosive, corrosive gas or dust in the installation place of the frequency conversion control cabinet;
2. Confirm that there is no severe vibration at the installation place of the frequency conversion control cabinet. Reserve a maintenance channel during installation;
3. Confirm that the ambient temperature is between -5 ¡ã C and 40 ¡ã C, the relative humidity does not exceed 90% at normal temperature, and there is no condensation; if the ambient temperature and humidity exceed this requirement, a specially designed inverter control cabinet is required.
4. The power supply fluctuates between -10%-+ 10.
5. The altitude does not exceed 1000 meters.
Preparation before commissioning: confirm whether the control cabinet installation is in place; confirm whether the wiring inside the cabinet is loose or disconnected; confirm again whether the wiring of the inverter is incorrect, whether the DC and AC wiring are incorrect; whether the main power wiring is correct; whether the motor wiring is correct Correct; whether the cable model matches the selected motor (load); whether the rated power of the inverter is greater than or equal to the rated power of the selected motor; if it is a heavy load, the rated power of the inverter is greater than the motor power by one or two Grade; whether the setting value of the thermal relay is correct. Are there any extra wires or foreign objects in the cabinet? Close the main power circuit breaker and test once, and quickly disconnect it to see if the wiring is correct and the phase sequence is correct.
Debugging: There are no problems in the above links. According to the control requirements of the on-site process, set the parameters strictly in accordance with the instruction manual of the inverter. After setting, confirm whether the motor rated power, rated voltage, rated current and other parameters are correct, the protection parameters are set correctly, and the control method meets the process control requirements. After confirming that there is no error, start the test run, and judge whether it needs to be modified based on the signal on site Set the parameter value. For closed-loop control, especially constant pressure control, first adjust the P parameter when setting the PID. Generally, it is slowly adjusted from small to large. If the P parameter is set large, the system's adjustment speed is fast and it is easy to cause system oscillation and integration. The parameter can not be set too short. If the integration time is too short, the integral regulator will be too strong and repeated overshoot will occur, making the system unstable until oscillation occurs. The integration time is generally adjusted from large to small, gradually adjusting the integration time, and observing the adjustment effect of the system until the stable speed of the system reaches the requirements.
The product is returned for one month and three months after the product is sold. The warranty is free within one year. For technical assistance during the life-long maintenance service, the company has set up a professional customer service for marketing services to provide users with free pre-sale, sale, After-sale technical consultation and installation and commissioning guidance, solve the problems raised by users. 24-hour service hotline: 400-0940-400
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