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Q1: What are permanent magnet motors and permanent magnet fans?

Permanent magnet means that once magnetized it can maintain constant magnetism. The material with this constant magnetism is permanent magnet material. The commonly used permanent magnet materials are divided into Al-Ni-Co permanent magnet alloy, Fe-Cr-Co permanent magnet alloy, permanent magnet ferrite, rare-earth permanent magnet material, and composite permanent magnet material. Among which rare-earth permanent magnet materials mainly include rare-earth cobalt permanent magnet material and rare-earth NdFeB permanent magnet material. The former is an intermetallic compound formed by rare-earth elements cerium, praseodymium, lanthanum, neodymium and cobalt, and its magnetic energy volume can reach 150 times of carbon steel, 3 ~ 5 times of aluminum nickel cobalt permanent magnet material, 8 ~ 10 times of permanent magnet ferrite, low temperature coefficient, stable magnetism, up to 800 kA/m coercivity. It is mainly used in low speed torque motors, starter motors, sensors, magnetic bearings and other magnetic systems. rare-earth NdFeB permanent magnet material is the 3rd generation of rare-earth permanent magnet material. Its remanence, coercivity and maximum magnetic energy product ratio are higher than the former, and it is not easy to be broken. It has good mechanical properties and low alloy density, which is conducive to light weight, thin, miniaturization and ultra-miniaturization of magnetic components. However, its high magnetic temperature coefficient limits its application (note: We CTID uses rare-earth NdFeB permanent magnet materials). The motors that use permanent magnet materials to provide excitation are permanent magnet motors. Fans using permanent magnet motors are permanent magnet fans.

Q2: What are the advantages and shortages of permanent magnet motors compared with ordinary motors?

The structure of permanent magnet motor is simple. It reduces the cost of processing and assembly, eliminates the collector ring and brush that are prone to get problems, and improves the reliability of motor operation. And because there is no excitation current, no excitation loss, the efficiency and power density of the motor are improved. On the contrary, ordinary motors are electric excitation motors, the excitation winding loss and heat condition are often the weak links of the ventilation and heat dissipation system. In simple terms, comparing with ordinary motors, permanent magnet motors are smaller, lighter, fewer consumable, more efficient and energy-saving, lower temperature, better starting performance, higher power factor and power density, stronger overload resistance. The disadvantage is higher unit price due to higher manufacturing cost, so it needs to use the excellent performance and the low operation cost (high efficiency and energy saving) as compensation. In the actual cases, the electricity saving is considerable, it has produced good economic benefits.