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​32 application fields of frequency converter

Oct 13, 2020

32 application fields of frequency converter

Variable-frequency Drive, VFD is a power control device that uses variable frequency technology and microelectronics technology to control AC motors by changing the frequency of the motor's working power supply. The frequency converter is mainly composed of rectifier (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, detection unit and micro processing unit. The inverter adjusts the voltage and frequency of the output power supply by the opening and closing of the internal IGBT, and provides the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. In addition, the inverter has many protection functions. , Such as overcurrent, overvoltage, overload protection and so on. With the continuous improvement of industrial automation, frequency converters have also been widely used.

    Then according to SAFESAVE Electric’s industry experience over the years, inverters can be mainly used in 32 classic industry fields, such as: air conditioning load, crusher load, large kiln calciner load, compressor load, rolling mill Load, converter load, hoist load, roller load, pump load, crane, dump truck load, wire drawing machine load, transport vehicle load, elevator overhead tourist car load, feeder load, pile Reclaimer load, fan load, mixer load, spinning machine load, special power supply load, etc.

    Below we will analyze the specific applications in these industries:

    1. The inverter is used in air-conditioning loads

    Office buildings, shopping malls, some supermarkets, and factories all have central air conditioners. At the peak of summer electricity consumption, air conditioners consume a lot of electricity. In hot weather, air-conditioning power consumption in Beijing, Shanghai, and Shenzhen all account for more than 40% of peak power. Therefore, using a frequency conversion device to drive the refrigeration pump, cold water pump, and fan of the air conditioning system is a very good power saving technology. At present, many companies specializing in short-selling electricity regulation have emerged across the country, and the main technology is frequency conversion speed regulation and electricity saving.

    2. The frequency converter is applied to the load of crusher

    Many crushers and ball mills are used in metallurgical mines and building materials. The effect of frequency conversion for this type of load is significant.

    3. The frequency converter is used in the load of large kiln calciners

    Large-scale industrial rotary kilns (converters) such as metallurgy, building materials, and caustic soda used mostly DC, commutator motors, slip motors, cascade speed regulation or intermediate frequency unit speed regulation. Because these speed regulation methods may have slip rings or low efficiency, in recent years, many units have adopted frequency conversion control with excellent results.

    4. The frequency converter is used in compressor loads

    Compressors are also widely used loads. Low-pressure compressors are commonly used in various industrial sectors, and high-pressure large-capacity compressors are widely used in iron and steel (such as oxygen generators), mines, fertilizers, and ethylene. The use of frequency conversion speed regulation brings advantages such as low starting current, energy saving, and optimization of equipment service life.

    5. The frequency converter is used in rolling mill load

    In the metallurgical industry, in the past, large-scale rolling mills used AC-AC inverters. In recent years, AC-DC-AC inverters have been used. AC conversion of rolling mills has become a trend, especially in light-load rolling mills, such as the multi-stands of Ningxia National Aluminum Products Factory. The aluminum rolling mill adopts a general frequency converter to meet the low frequency load start, synchronous operation between the stands, constant tension control, simple and reliable operation.

    6. The frequency converter is used in hoisting load

    The hoist type load adopts frequency conversion speed regulation, which is stable and reliable. The blast furnace hoisting equipment of the iron plant is the main ironmaking raw material conveying equipment. It requires smooth starting and braking, uniform acceleration and deceleration, and high reliability. In the past, cascade, DC or rotor series resistance speed regulation methods were mostly used, which has low efficiency and poor reliability. Using AC frequency converter to replace the above-mentioned speed regulation method can achieve ideal results.

    7. The frequency converter is used in converter load

    For converter-type loads, it is simple and reliable to use AC frequency conversion instead of DC unit, and the operation is stable.

    8. The frequency converter is used in roller type loads

    Roller type loads, mostly in the steel and metallurgical industry, adopt AC motor frequency conversion control, which can improve equipment reliability and stability.

    9. The frequency converter is used in pump loads

    The pump load has a large volume and a wide range, including water pumps, oil pumps, chemical pumps, mud pumps, sand pumps, etc. There are low pressure medium and small capacity pumps, and high pressure large capacity pumps.

    Many water company pumps, chemical pumps in the chemical and fertilizer industries, reciprocating pumps, and mud pumps in non-ferrous metal industries use variable frequency speed regulation, all of which produce very good results.

    10. The frequency converter is used in cranes and dump trucks.

    Cranes, dump trucks and other load torques are large and require stability, frequent positive and negative, and require reliability. Frequency conversion devices control cranes and dump trucks can meet these requirements.

    11. The frequency converter is applied to the load of wire drawing machine

    The wire drawing machine for producing steel wire requires high-speed and continuous production. The steel wire strength is 200Kg/mm2, and the speed control system requires high precision, high stability and synchronization.

    12. The frequency converter is used in transporting vehicle loads

    The use of frequency conversion technology for raw coal loading vehicles in coal mines or molten steel transport vehicles in steel mills is very effective. Quick start and stop, strong overload capacity, flexible forward and reverse rotation, to achieve a flat coal surface and correct weight (no more or less loading), basically no manual operation is required, which improves the production efficiency of raw coal and saves electricity.

    13. The frequency converter is applied to the load of elevator overhead tourist car

    Because the elevator is a manned tool, the driving system is required to be highly reliable, and frequent acceleration, deceleration, and forward and reverse rotation are required. The improvement of the dynamic characteristics and reliability of the elevator increases the safety, comfort and efficiency of the elevator. In the past, elevator speed control was mostly DC. In recent years, it has gradually changed to AC motor variable frequency speed control, whether in Japan or Germany. Many elevator factories in my country are scrambling to equip elevators with frequency conversion speed regulation. For example, Shanghai Mitsubishi, Guangzhou Hitachi, Qingdao Fuji, Tianjin Otis, etc. all adopt AC frequency conversion speed control. Many elevators originally produced have also undergone frequency conversion transformation.

    14. The frequency converter is applied to the load of the feeder

    There are many feeders in metallurgy, electric power, coal, chemical and other industries. Whether it is a disc feeder or a vibrating feeder, the frequency conversion speed control effect is very significant. The disc feeder of the sulphuric acid production line of Jilin Chemical Company’s dye plant was originally designed for slip speed regulation, with small low-frequency torque, many failures, and frequent jamming. After adopting frequency conversion speed regulation, because it is an asynchronous machine, it has high reliability and energy saving. More importantly, the closed loop with the temperature transmitter ensures the accuracy of the conveyed materials, and prevents accidents caused by excessive and over-temperature conveying of oxidant, ensuring production The orderliness.

    15. The frequency converter is applied to the load of stacker and reclaimer

    Stacker-reclaimer is the main equipment for stacking and reclaiming materials in coal yards, docks, and mines. Its main function is stacking and reclaiming materials. The realization of automatic stacking and semi-automatic reclaiming improves the reliability of the equipment, and the equipment runs smoothly without impact and shaking. The reclaiming process is rotated according to the 1/cosφ rule, which improves the efficiency of the bucket wheel reclaiming and the belt conveying coal. The uniformity is very popular among workers.

    16. The frequency converter is used in fan loads

    Fan load is a wide range of equipment, steel mills, power plants, non-ferrous metals, mining, chemical, textile, chemical fiber, cement, paper and other industries are widely used. Most of them use adjusting the opening of the baffle to adjust the air volume, which wastes a lot of electric energy. Using frequency conversion speed control can save electricity and reduce mechanical wear and extend the life of the equipment.

    17. The frequency converter is applied to the load of mixer

    There are many mixers in the chemical and pharmaceutical industries, and the use of frequency conversion speed control instead of other speed control methods has many advantages.

    18. The frequency converter is used in spinning machine load

    The spinning process is complicated, there are many stations, tension control is required, and some require position control. The frequency conversion speed regulation effect is good.

    19. The frequency converter is used in special power loads

    Many power supplies, such as experimental power supplies and aircraft drag power supplies (400Hz) can be completed with frequency conversion devices. The advantages are low investment, quick results, small size and simple operation.

    20. The frequency converter is used in paper machine load

    The paper machines in my country's paper industry mostly use SCR DC speed regulation methods that require high precision, and some use slip motors and commutator motors. Due to the existence of slip rings and carbon brushes, the reliability and accuracy are not high. As a result, the papermaking machinery is backward, and the general speed is only about 200m/min, which is difficult to compare with 2000m/min abroad. Therefore, the frequency conversion of papermaking machinery is the general trend.

    21. The frequency converter is used in washing and ironing equipment loads

    In the past, washing machines and ironing equipment in larger hotels mostly used mechanical speed regulation or pole-changing speed regulation, which could only provide one speed or several speeds, which is not ideal for fabrics that require repeated washing and ironing. The use of frequency conversion speed regulation greatly improves the efficiency of the washing machine.

    22. The frequency converter is applied to the load of music fountain

    The music fountain that attracts tourists very much, its water level and volume are controlled by frequency conversion.

    23. The frequency converter is applied to mechanical loads such as grinders

    The spindle of the grinder is concerned about the high speed, and the frequency of the power supply is also high, including 200Hz, 400Hz or even 800Hz. In the past, the power supply of the spindle motor was mostly driven by an intermediate frequency generator set. The intermediate frequency unit is large in size, low in efficiency, noisy, and poor in accuracy.

    24. The frequency converter is applied to the cigarette machine load

    The cigarette machines imported by the cigarette industry in the past, whether Maureen 8 or Maureen 0, are not stepless speed regulation. Therefore, in the cigarette industry, it is mainly to solve the problem of stepless speed regulation and reliability. The technology is simple, the frequency converter is simple to use, and the effect is great.

    25. The frequency converter is used in vibration reduction and noise reduction load

    Many loads, such as large air compressors and intermediate frequency units, have high noise and vibration. Using frequency conversion technology can reduce vibration and noise, within the standard.

    26. The frequency converter is applied to the load of printing and dyeing machine

    Most printing and dyeing machinery is a multi-unit joint work equipment. The technology requires all units to run synchronously at the same linear speed and maintain a constant tension, otherwise quality problems such as cloth breakage, entanglement, uneven chromaticity, insufficient color, and excessive shrinkage will occur. In the past, printing and dyeing machinery used DC speed control system whether it was a common power supply mode or a sub-power supply mode.

    Because of the inherent shortcomings of DC, the printing and dyeing industry gradually adopts AC frequency conversion technology. The rotary screen printing machine is composed of a cloth feed unit, a printing unit, a drying room guide belt unit and a cloth drop unit. It is a complex type of printing and dyeing speed control system. Using frequency conversion speed control to form a speed chain control. Good synchronization performance, high precision and high reliability.

    27. The inverter is used in injection molding machine loads

    Injection molding machines are the key equipment for plastic processing and molding. They are large in number and consume large amounts of electricity. In the past, most energy-saving methods used delta (triangle) type (triangle type) to Y type (star type) to save electricity. Using frequency conversion speed regulation does not change the original structure of the injection molding machine, and controls the pressure or flow of several processes of the oil pump (such as mold clamping, mold clamping, injection, pressure holding, demolding, mold withdrawal, etc.), which can save power by 20%~52 %, it has better replaced the past proportional valve throttling speed regulation method, and greatly reduced energy consumption. Many injection molding plants in the Pearl River Delta have carried out frequency conversion transformation. When transforming the injection molding machine, pay attention to the acceleration of mold clamping, otherwise the output will be reduced, and pay attention to the harmonic interference at the input and output ends.

    28. The inverter is used in environmental protection loads such as sewage treatment

    More and more attention is paid to environmental protection, which is related to the environment on which humans depend. So clean energy and green cities have appeared. Variable frequency speed regulation can be used in three aspects of environmental protection loads. The first is industrial sewage treatment, the second is garbage power plants, and the third is the control of industrial smoke, exhaust, and dust removal.

    29. The inverter is used in the production line load of glass, ceramics, pharmaceuticals, beverages, food, packaging, etc.

    The production lines of glass, ceramics, pharmacy, beverage, food, packaging, etc. adopt frequency conversion speed regulation, and all have achieved good results.

    30. The frequency converter is applied to the load of offshore oil production platform

    It is much better to use AC motor variable frequency speed regulation in oil drilling than DC speed regulation, especially in places with heavy sand and dust, because AC motors are reliable. Offshore oil drilling platforms require variable frequency speed regulation devices.

    31. The frequency converter is used in submersible electric pump loads

    Electric submersible pump oil extraction is a way of oil extraction in oil fields. Electric submersible pumps mostly work in oil wells below 1800m. Most of them use power frequency full pressure start and constant speed operation. They have the following disadvantages:

    ☆Excessive starting current will damage the motor insulation

    ☆ Produce impact torque and damage the pump structure;

    ☆ The pump suddenly produces a large suction force, which is easy to suck in sand, causing the pump to jam. In addition, there is no voltage-stabilizing system and large fluctuations in the downhole liquid level, resulting in unstable voltage and current, causing the submersible motor to be over-excited and under-excited, causing malfunctions.

    32. The frequency converter is used in polyester chip loads

    Polyester chips are one of the main products in the petrochemical industry. Due to the high precision of frequency conversion speed regulation, it is convenient for multiple control points to control, stable and reliable, and the use of frequency conversion speed regulation can increase product quality and bring great benefits to enterprises. Many companies use frequency conversion technology when expanding capacity.