Magnet motors are very common and they are made from varying motor magnetic assemblies depending on the motor features and applications. They work on an electromagnetic cold that gets attracted to the permanent magnet within the motor assembly. The attraction causes the motor to rotate and once the electrical power source is removed then the wire loses the magnetic qualities stopping the motor in the process. The motion and rotation of permanent magnet motors can be managed by a motor driver which controls the duration and when electricity allows the motor to rotate.
Magnets and assemblies for motors, actuators and generators are in many types. Ferrite or rare earth magnets are mostly used in magnetic motors and other vehicle applications. They are stronger compared to ferrite or ceramic magnets and this makes them better performers even in lighter and smaller motors. They tend to be more expensive compared to ferrite options. Below is a breakdown of the commonly used magnets for motor applications.
Samarium cobalt magnets
They are perfect for high temperature motor applications because they have high magnetic strength, reliable performance and temperature resistance that is unmatched. They are also resistant to corrosion meaning that they do not even require surface coating or plating for most applications. This is a quality that makes them suitable for medical applications as well. They have temperature stability too compared to neodymium magnets and can operate between 250 to 550 degrees.
These mostly feature in electric car motor applications. They are actually part of most parts of the vehicle from the motor that spins DVD discs to hybrid car wheels. Mostly the choice between neodymium or cobalt magnets for motor applications depends on the corrosion resistance levels required and operating temperatures expected. They come in low coercivity and high coercivity grades. Lower grade losses strength when heated above 80C whereas the high grade can function in up to 220C with minimal irreversible loss. Neodymium magnets for motor applications are corrosion vulnerable and this can lead to deterioration such as crumbling of the magnet to small powdery particles. For this reason, an additional protective coating may be necessary to prevent reactions that come from atmospheric exposure. They can be nickel plated or layered with copper-nickel plating.
They may be low in energy compared to neodymium magnets, but they are resistant to demagnetization and corrosion and are also low priced making them quite affordable. The ceramic magnets can operate at 250C but they loss their magnetic properties when the temperatures are elevated beyond this. On the other hand, they are not very good performers in cold temperatures. When exposed to -20C, then can experience permanent magnetic strength loss unless in situations where the circuit is designed to be functional even in such extremes. The ceramic magnets offer excellent corrosion resistance and will not in most cases require any plating or coating.