Magnetic brake, also known as magnetic retarder, is a non-contact braking device that converts kinetic energy into heat energy through electromagnetic induction to achieve deceleration and braking. It is mainly used as an auxiliary braking system in vehicles (such as commercial vehicles, buses, and heavy-duty trucks) to reduce the load on the main braking system, improve driving safety, and extend the service life of friction brakes.

The working principle of a magnetic brake is based on the eddy current effect. It consists of a stator (equipped with electromagnets) and a rotor (connected to the vehicle's transmission system). When the electromagnet is energized, a stationary magnetic field is formed in the stator; as the rotor rotates with the vehicle's wheels, the conductive material of the rotor cuts the magnetic field lines, generating eddy currents inside the rotor. The eddy currents interact with the magnetic field to produce a damping torque that opposes the rotation of the rotor, thereby achieving deceleration and braking.

Compared with traditional friction brakes, magnetic brakes have the advantages of no mechanical wear, no need for cooling with brake fluid, and continuous braking capacity. They are particularly effective in long downhill sections, where they can continuously provide braking force to prevent brake fading caused by overheating of friction brakes. In addition, magnetic brakes operate with low noise and smooth braking force, improving the comfort of vehicle operation. With the continuous development of automotive technology, magnetic brakes are increasingly used in new energy vehicles to enhance braking efficiency and energy recovery performance.