Principles of Linear Motors
Linear motors operate based on the principle of attraction and repulsion between magnets.
In this regard, they are similar to conventional motors. However, linear motors adopt a structure that is like a sliced version of traditional motors to generate linear motion.
Therefore, they differ in principle from traditional motors, which have a mechanical shaft and are driven by torque. Additionally, like conventional motors, linear motors can be categorized into induction types, which rely on the Lorentz force generated by electromagnetic induction for driving, and synchronous types, which utilize the repulsion and attraction of magnetic poles. Induction-type linear motors consist of magnets arranged with alternating NS-SN poles, with electromagnets placed alongside them, and are driven by the flow of electric current.
On the other hand, in synchronous-type linear motors, to move the movable electromagnets over the linearly arranged fixed magnets, the magnetic poles of the fixed magnets change in synchronization with the movement of the movable electromagnets.
In general, maglev trains adopt synchronous-type linear motors to reduce power consumption, while induction-type ones are used in applications such as axis motors for industrial machinery that require precise control.
Particularly in maglev trains, superconducting magnets are used for the electromagnets on the vehicle body, minimizing the supply of electric power.
