In 1880, American inventor Edison created a large DC generator called “The Colossus”, which was exhibited at the Paris Exposition in 1881.
edison the father of direct current
At the same time, the development of the electric motor is also in progress. Generator and motor are two different functions of the same machine. Using it as a current output device is a generator, and using it as a power supply device is a motor.
This reversible principle of the electric machine was proved by chance in 1873. At an industrial exhibition in Vienna this year, a worker made a mistake and connected a wire to a running Gram generator. It was found that the rotor of the generator changed direction and immediately went in the opposite direction. The direction turns and becomes a motor. Since then, people have realized that the DC motor can be used as both a generator and a reversible phenomenon of the motor. This unexpected discovery has had a profound impact on the design and manufacture of the motor.
With the development of power generation and power supply technology, the design and manufacture of motors are also becoming more and more perfect. By the 1890s, DC motors had all the main structural features of modern DC motors. Although the DC motor has been widely used and has produced considerable economic benefits in the application, its own shortcomings restrict its further development. That is, it cannot solve long-distance power transmission, nor can it solve the problem of voltage conversion, so AC motors have developed rapidly.
During this period, two-phase motors and three-phase motors came out one after another. In 1885, the Italian physicist Galileo Ferraris proposed the principle of rotating magnetic field and developed a two-phase asynchronous motor model. In 1886, Nikola Tesla, who moved to the United States, also independently developed a two-phase asynchronous motor. In 1888, Russian electrical engineer Dolivo Dobrovolsky made a three-phase AC single squirrel cage asynchronous motor. The research and development of AC motors, especially the successful development of three-phase AC motors, has created conditions for long-distance power transmission, and at the same time has improved electrical technology to a new stage.
Tesla, the father of alternating current
Around 1880, the British Ferranti improved the alternator and proposed the concept of AC high-voltage transmission. In 1882, Gordon in England produced a large two-phase alternator. In 1882, the Frenchman Gorand and the Englishman John Gibbs obtained the patent of “Lighting and Power Distribution Method”, and successfully developed the first transformer with practical value. most critical equipment. Later, Westinghouse improved the construction of the Gibbs transformer, making it a transformer with modern performance. In 1891, Blow made a high-voltage oil-immersed transformer in Switzerland, and later developed a giant high-voltage transformer. Long-distance high-voltage AC power transmission has made great progress due to the continuous improvement of transformers.
After more than 100 years of development, the theory of the motor itself has been quite mature. However, with the development of electrical engineering, computer science and control technology, the development of the motor has entered a new stage. Among them, the development of AC speed regulation motor is the most eye-catching, but it has not been popularized and applied for a long time because it is realized by circuit components and rotary converter units, and the control performance is not as good as that of DC speed regulation.
After the 1970s, after the power electronic converter was introduced, the problems of reducing equipment, reducing size, reducing cost, improving efficiency, and eliminating noise were gradually solved, and AC speed regulation achieved a leap forward. After the invention of vector control, the static and dynamic performance of the AC speed control system was improved. After adopting microcomputer control, the vector control algorithm is realized by software to standardize the hardware circuit, thereby reducing the cost and improving the reliability, and it is also possible to further realize more complex control technology. The rapid progress of power electronics and microcomputer control technology is the driving force for the continuous update of the AC speed control system.
In recent years, with the rapid development of rare earth permanent magnet materials and the development of power electronics technology, permanent magnet motors have made great progress. Motors and generators using NdFeB permanent magnet materials have been widely used, ranging from ship propulsion to artificial heart blood pumps. Superconducting motors are already used for power generation and the propulsion of high-speed maglev trains and ships.
With the advancement of science and technology, the improvement of the performance of raw materials and the improvement of the manufacturing process, the motors are being produced with tens of thousands of varieties and specifications, power levels of different sizes (from a few millionths of a watt to more than 1000MW), and a very wide speed. Range (from several days to hundreds of thousands of revolutions per minute), very flexible environmental adaptability (such as flat ground, plateau, air, underwater, oil, cold zone, temperate zone, wet tropics, dry tropics, indoor, outdoor, Vehicles, ships, various media, etc.), to meet the needs of various sectors of the national economy and human life.
Post time: Feb-04-2023
