Magnets In Electric Motors

We all know that magnets are commonly used on motors, but the magnets used by different motors are not only different sizes, but also different shapes. The basic shapes are arc/wedge/bread-shaped, rectangle, ring and flat block shapes, Let's talk about their respective characteristics.

Arc magnet in motor

Motor arc magnets, also often referred to as tiles shape magnet, segment shape magnet, wedge shape magnet, bread magnet, etc.

Curved segment magnets are the most commonly used magnet shapes for electric motors, especially for DC motors and magnetic rotors. The curved magnet will bring the magnet closer to the stator. So it can reduce the air gap and increase the flux between them. In addition, it also has the effect of reducing vibration and noise.

Below is a image of ferrite arc magnet used in motor:

Ring magnet in motor

Motor ring magnets

In theory, a ring magnet is the best shape for a motor magnet. More precisely, these rings are radial toroidal motor magnets. They have many of the following advantages:

1. Easy to assemble

2. Good stability

3. Better geometric accuracy

4. Excellent motor performance

5. A variety of magnetization directions

6. The magnetic field is evenly distributed

However, due to the limitation of material properties and manufacturing process, not all magnets can be made into radially oriented rings. There are two main radial ring magnets. One is a bonded neodymium magnet and the other is a sintered neodymium magnet.

Molded magnets are designed for different motors such as pump motors, vacuum motors, gated motors, stepper motors, brushless motors, DC motors, starting motors and conveying motors. They are made by hot extrusion and deformation.

Compared with sintered neodymium magnets, injection molded ferrite magnets, samarium cobalt magnets or injection molded neodymium magnets have advantages in terms of control accuracy and yield. They are the most flexible permanent magnets and can be magnetized in a variety of ways to make different complex shapes. But the magnetic field is much lower than the sintered chin-iron boron magnet.

Sintered NdFeb magnets can also be made into radially magnetized magnetic rings. But the cost is very expensive because they require additional magnetizing clamps and magnetizing coils. There are also many limitations on size and grade.

Below is a image of NdFeb ring magnet:

Flat square block magnet in motor

Flat (trapezoidal and rectangular) shapes are another common choice for motor magnets. Flat shape is easy to process for motor magnet manufacturers. This means lower costs than segment motor magnets.

The above is an rough introduction to the shape types and advantages of electric motor magnets. As a permanent magnet manufacturer, we also have various types of neodymium motor magnets and ferrite motor magnet ring/arc/Squre to choose from. If you have needs, please contact us.

Motor magnet products please click:

NdFeb/ferrite motor arc magnet

DC ceiling fan motor arc shaped ceramic ferrite magnet