The development of Permanent Magnet Generator is closely related to the development of permanent magnet material. China is the world's first discovery of magnetic properties of permanent magnet materials and applied it to practice in the country, more than two thousand years ago, China's use of magnetic properties of permanent magnetic materials made compass, in the maritime, military and other fields to play a huge Role, as one of China's four major inventions.
High-efficiency permanent magnet synchronous motor permanent magnet synchronous motor compared with the induction motor, does not require reactive excitation current, can significantly improve the power factor (up to 1, or even capacitive), reducing the stator current and stator resistance loss, Running without the rotor copper consumption, which can reduce the fan (small capacity motor can even remove the fan) and the corresponding wind friction loss, efficiency than the same specifications induction motor can be increased by 2 to 8 percentage points. Moreover, the permanent magnet synchronous motor in the 25% ~ 120% rated load range can maintain a high efficiency and power factor,Permanent Magnet Generator so that the light load operation energy saving effect is more significant. This type of motor is generally set on the rotor starting winding, with a frequency and voltage directly under the ability to start. At present the main application in the oil field, textile and chemical fiber industry, ceramic glass industry and the long running time of the fan pumps and other fields.
Permanent magnet materials used in the motor, including sintered magnets and bonded magnets, the main types of aluminum nickel cobalt, ferrite, samarium cobalt and NdFeB and so on.
Alnico materials are used more by the 1980s. It has excellent temperature stability, time stability and the use of ultra-high temperature conditions such as the use of environmental conditions, in some special applications such as the use of high temperature requirements, magnetic stability is very good military or instrumentation and other special use of the environment only used in the motor The , Ferrite materials are non-metallic permanent magnet materials, low prices. It is mainly used for the use of performance and volume requirements are not high and wide range of economic series of micro-motor products. Such as toy motor,Permanent Magnet Generator household electrical appliances, audio and video motor, office equipment and general instrument motor, motorcycles and motor vehicles and industrial low-power drive motor.
SmCo material is the 20th century, the mid-60s the rise of the magnetic properties of the permanent magnetic material, and the performance is very stable. SmCo is particularly suitable for manufacturing motors in terms of magnetic properties, but because of its high cost, it is mainly used in the research and development of high-tech motors in the field of aerospace, military and other military motors and high performance and not the main factor. NdFeB material is known as the third generation of high-performance permanent magnetic materials in the 1980s. Magnetic properties higher than SmCo, poor thermal stability, and easy to rust, must be surface protection, but the price is cheap , So quickly to promote the application. With the NdFeB material constantly updated,Permanent Magnet Generator the temperature performance improved, especially since the 20th century, 90 years, low temperature coefficient, high temperature NdFeB material has been successfully developed, high-performance heat-resistant NdFeB working temperature up to 200 ℃, and the price is also reduced, so that most of the industrial and civilian motor are used NdFeB material, and will replace most of the original ferrite materials and used in low-cost economy.
Bonded permanent magnet material is a composite permanent magnet material made by mixing the binder and the permanent magnet material after compression, injection or extrusion molding, including bonded ferrite, bonded aluminum nickel cobalt, sticky Ce samarium and bonded NdFeB. Which bonded NdFeB is the best bonded permanent magnet material. Compared with the sintered permanent magnet material,Permanent Magnet Generator it has the advantages of good machinability, easy molding, can be made into various complex shapes, good magnetic uniformity and easy to multi-pole magnetization and so on. However, the magnetic properties of the bonded permanent magnet materials are lower than those of the same type of sintered magnets, and the magnetic energy product is about 40% to 70% of the sintered magnets of the same material. In the bonded permanent magnet materials, the best prospects for bonding NdFeB, bonded NdFeB if the process to solve the problem and improve the quality, will become the most widely used permanent magnet materials. It is mainly used for small brushless DC motors and stepper motors and other precision micro-motor.