The birth of earth permanent magnets marked a generational change in a new class of materials. Rare earth permanent magnet motors emerged at the historic moment and played a huge role in the progress of human production. So what are the design principles for medium-sized earth permanent magnet motors? Let’s discuss it together below!
Rare earth permanent magnets are a type of material with magnetic properties that emerged in the late 1960s. Used to make motors, they can reduce size, weight, reduce losses, simplify the structure, and improve reliability. my country is rich in earth resources, accounting for more than 80% of the world's reserves. Therefore, the promotion and application of earth permanent magnets has important strategic significance and social and economic benefits.
With the sponsorship of the National Natural Science Foundation (Grant No.: 5830054), Professor Tang Renyuan of Shenyang University of Technology and his research team conducted a systematic study on the design and principles of earth permanent magnet motors. Rare earth permanent magnets obtained the patent in 1987. Breakthrough effects.
In terms of improving design accuracy, the three-dimensional static magnetic field and two-dimensional transient field containing permanent magnets were successfully calculated, the internal magnetic field distribution rules and transient change rules of earth permanent magnets were clarified, and the electromagnetic parameters and parameters of various typical structures were sorted out. Its saturation curve; on this basis, using the method of combining "field" and "road", the electromagnetic calculation program was derived, and software that can be used on a personal computer was compiled.
In the key technical aspect of overcoming the difficulty of starting earth permanent magnet motors, a computer simulation study was conducted on the dynamic starting function of earth permanent magnets, and the transient change rules of voltage, current, torque, speed, etc. during the starting process were clarified. , which provides a basis for improving the design.
In terms of testing, the parameter testing method of earth permanent magnet motors under magnetized conditions was studied, and the transient torque speed testing equipment and two-dimensional magnetic field testing equipment were successfully developed for the time in China.
Based on the above research results, earth permanent magnet generators with various standards of 40 to 160 kVA have been successfully developed in cooperation with Harbin Electric Machinery Factory, Dongfang Electric Machinery Factory, and Shanghai Electric Machinery Factory. They are all earth permanent magnet generators with the capacity in the world. The technical and functional indicators of the auxiliary exciter have also reached the international advanced level, and have been unanimously praised and highly praised by domestic and foreign permanent magnet materials and earth permanent magnet peers. Among them, the 75 kVA earth permanent magnet generator won the second prize of the National Science and Technology Progress Award in 1985 and the second prize of the former Ministry of Machinery Industry Science and Technology Progress Award. The 60 kVA earth permanent magnet generator won the former Ministry of Machinery Industry Science and Technology Progress Award. second prize.
The above-mentioned earth permanent magnet motors have been produced in batches and used in large thermal power stations to improve the reliability of power plant operation. According to statistics from the power department, more than 50% of the demagnetization accidents that occurred in domestic turbine generators in the past were caused by the auxiliary exciter. Since 1984, no such accident has occurred in any steam turbine generator set equipped with domestic earth permanent magnets as auxiliary exciters. By the end of 1988, 74 sets of earth permanent magnet auxiliary exciters had been put into operation, enabling the power plant to generate an additional 191 million kWh of electricity, increase revenue by 12.73 million yuan, and increase national economic output by 573 million yuan. Not only has it replaced imports, but the 200,000-kilowatt turbine generator set using this motor has been exported to Pakistan, earning US$4 million in foreign exchange.
Because of its breakthrough development in theoretical research and practical application of earth permanent magnet motors, this achievement won the prize of the Liaoning Provincial Science and Technology Progress Award in 1989.
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