What are the precautions for permanent magnet motors?

Since the emergence of permanent magnet motors, of them have been used in factories and some large engineering companies. The cooling system of this motor has the advantages of simple structure, small size, and low noise, so it is loved by people. Of course, when using this motor, there is one thing that needs to be paid attention to, and that is the maintenance of the permanent magnet motor. There are also some other precautions. Let’s learn what the precautions for the permanent magnet motor are below!

1. Magnetic circuit structure and design calculation

In order to give full play to the magnetic functions of various permanent magnet materials, especially the magnetic functions of earth permanent magnets, and to produce a cost-effective permanent magnet motor, we cannot simply apply the structure and design calculation methods of traditional permanent magnet motors or electric excitation motors. , a new design concept must be established, and the magnetic circuit structure must be reanalyzed and improved. With the rapid development of computer hardware and software skills, as well as the continuous improvement of modern design methods such as electromagnetic field numerical calculation, design and simulation skills, through the joint efforts of the electrical academia and the engineering community, the design theory and design of permanent magnet motors have been greatly improved. Breakthroughs have been made in calculation methods, structural technology and control technology, and a complete set of analysis and research methods and computer-aided analysis and design software that combine electromagnetic field numerical calculations and equivalent magnetic circuit analytical solutions have been formed, and are being continuously improved. middle.

2. Control issues

After the permanent magnet motor is made, it can maintain its magnetic field without external energy, but it will also make it ly difficult to adjust and control its magnetic field from the outside. It is difficult to adjust the output voltage and power factor of a permanent magnet generator from the outside, and the permanent magnet DC motor can no longer adjust its speed by changing the excitation. These restrict the application range of this motor. However, with the rapid development of power electronic devices and control technologies such as MOSFET and IGBT, permanent magnet motors can be used without magnetic field control and only control the armature. When designing, we need to combine three new technologies: earth permanent magnet materials, power electronic devices and microcomputer control, so that the motor can operate under new working conditions.

3. Irreversible demagnetization problem

If improperly designed or used, this motor may fail when the temperature is too high (neodymium iron boron permanent magnet) or too low (ferrite permanent magnet), under the effect of armature reaction caused by inrush current, or during severe mechanical vibration. Irreversible demagnetization, or loss of magnetization, may occur, causing the motor's function to decline or even become unusable. Therefore, it is necessary to not only study and develop methods and equipment for checking the thermal stability of permanent magnet materials suitable for use in motor manufacturers, but also to analyze the anti-demagnetization capabilities of various structural methods so that corresponding measures can be taken during design and production. Make sure this motor does not lose magnetism.

4. Cost issue

Ferrite motors, especially miniature permanent magnet DC motors, are widely used because of their simple structure and process, reduced weight, and a series of advantages such as lower total cost than electric excitation motors. Because earth permanent magnets are still relatively expensive, and the cost of earth permanent magnet motors is generally higher than that of electric excitation motors, it is necessary to use its high performance and operating cost savings to make up for it. In some cases, such as the voice coil motor of a computer disk drive, after the use of NdFeB permanent magnets, its performance has been improved accordingly, while the volume and mass have been significantly reduced, and the total cost has been reduced. When designing, it is not only necessary to compare functions and prices before deciding on a choice based on specific application occasions and requirements, but also to innovate structural processes and design optimization to reduce costs.