The world's first motor prototype is permanent magnet motor, at that time, the performance of permanent magnetic materials was poor,the electromagnetic motor accounted for the mainstream.
The advent of
AlNiCo permanent magnet made permanent magnet motor developing, but its price is relatively high,AlNiCo permanent magnet motor application is not wide. The low-cost ferrite appears to make permanent magnet motor applications increased greatly, the application were from the toy motor, audio video machine, automotive micro motor to industry drive and servo drive with small power etc. According to statistics,permanent magnet motor accounts for more than 92% of DC motor below 500W,most of them are ferrite permanent magnet motors.The use of ferrite has so far，but its magnetic properties are poor, not suitable for high performance motors,in 1960s there have been rare earth magnets, the maximum energy product is four times more than the aluminum-nickel-cobalt,and five times more than ferrite. The appears of Samarium-Cobalt magnets made high performance servo motor realized, but the price of
SmCo permanent magnet was high, which limited its application.
NdFeB permanent magnetic materials appeared in 1980s,only the working temperature and the temperature coefficient is less than Samarium-Cobalt magnets,other properties exceeded Samarium-Cobalt, NdFeB permanent magnet price was much lower than SmCo magnets. High performance permanent magnet and improving performance, will cause a huge change in the motor industry. All kinds of servo motors are expected,DC and AC, stepper motor will eventually transition to the permanent magnet motor, its application field is very wide, AC asynchronous motor will eventually be replaced by various types of permanent magnet motors.
