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Various Forms of Permanent Magnet Motors

2020-01-10 23:58:29 Volcano Motor Read

Fan EC Motor Permanent Magnet Synchronous Motor Selection Focus Part 12-Various Forms of Permanent Magnet Motors

DC Motor

Fan manufacturers chose EC motors to save energy for permanent magnet synchronous motors. However, permanent magnet motors are divided into various types of products according to different control strategies and different structures. There are many differences in appellation and performance. Today, we will elaborate on various types of permanent magnet motors and which permanent magnet motor is more suitable for fan applications.


Permanent magnet motor is divided into Brushless DC motor and permanent magnet synchronous motor according to two different back EMF waveforms of square wave and sine wave, thus generating different motor running noise, control precision and response speed. Permanent magnet motors are divided into surface-mounted or embedded type due to rotor structure. Both types of motors can be made into permanent magnet synchronous motors according to specific waveform design.


In addition to the various permanent magnet motors listed above, there is another type of permanent magnet motor called "asynchronous starting permanent magnet motor" in the market. this product can be either permanent magnet synchronous motor or Brushless DC motor. in the specific application process, it is closer to the use method of asynchronous motor.


IPM permanent magnet synchronous motor means that the rotor magnetic shoe of the motor is embedded and has all the characteristics of permanent magnet synchronous motor, such as low starting current, large starting torque, constant torque, better overload capability and weak magnetic performance of soft start, etc.

DC Motor


The rated efficiency of this type of motor is slightly lower than that of SPM permanent magnet synchronous motor with the same power. It can achieve relatively high efficiency with ultra-wide high efficiency range and low rotating speed or low load. IPM permanent magnet synchronous motor has greater overload capacity than SPM permanent magnet synchronous motor, and is widely applied to the scene of vehicles with frequent responsible changes and large speed regulation range.


Asynchronous starting permanent magnet synchronous motor is more like permanent magnet embedded into squirrel-cage asynchronous motor rotor. During starting, the motor is driven to rotate by squirrel-cage rotor. In steady state, the motor is driven to rotate by permanent magnet. Compared with pure permanent magnet synchronous motor, it can run without power supply from the controller. Because asynchronous starting permanent magnet synchronous motor has more rotor windings than permanent magnet synchronous motor, the copper loss of the same power should be higher than permanent magnet synchronous motor, and its rated efficiency is lower than asynchronous motor, but higher than common three-phase asynchronous motor. Asynchronous starting permanent magnet synchronous motor is the load characteristic of asynchronous motor, with small starting torque and large starting current. It is suitable for high-power and long-term constant-speed operation and can reduce the system cost.


SPM permanent magnet synchronous motor refers to that the rotor magnetic shoe of the motor is of surface-mounted type, and the motor has the characteristics of small starting current, large starting torque, soft start, etc. The overload capacity and weak magnetic performance are lower than IPM permanent magnet synchronous motor, and the high efficiency interval is lower than IPM permanent magnet synchronous motor, but the rated efficiency of the motor is higher than IPM permanent magnet synchronous motor.

 DC Motor


The control algorithm of this type of motor is simpler than that of IPM permanent magnet synchronous motor, and the development cost of customized demand is lower. SPM permanent magnet synchronous motor is suitable for fluid equipment such as fan and water pump. The motor load increases with the increase of rotating speed, and the range of rotating speed adjustment is small, and the maximum load is relatively constant.


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