Magnet in Permanent Magnet Motors

The biggest application field of rare earth permanent magnets is permanent magnet motors, commonly known as motors. In a broad sense, motors include electric motors that convert electrical energy into mechanical energy, and generators that convert mechanical energy into electrical energy. Both electric motors and generators use the law of electromagnetic induction or force as the basic principle of electrical equipment. The air gap magnetic field is a prerequisite for the working principle of electric motors. The air gap magnetic field generated by electric excitation is called an induction motor, and the air gap magnetic field generated by permanent magnets is called a permanent magnet motor.

The air gap magnetic field in permanent magnet motors is generated through permanent magnets, which do not require additional electrical energy or additional windings. Therefore, the biggest advantages of permanent magnet motors compared to induction motors are high-efficiency, energy-saving, small size, and simple structure. Therefore, the application of permanent magnet motors, especially in various small and micro motors, is very extensive.

The following figure is a simple working principle model of a permanent magnet DC motor. Two permanent magnets generate a magnetic field at the center of the coil, which is energized with current. When subjected to the magnetic field, it generates an electromagnetic force (left-handed rule), which then rotates. The rotating part of the motor is called the rotor, and the stationary part is called the stator. It is obvious that the permanent magnet in the figure below belongs to the stator, while the coil belongs to the rotor.