Electric Traction | Explain why LEM is called as wheel less drive.

LEM is called as Wheel Less Drive:  

Linear electric motor is a special type of induction motor which gives linear motion. It works on principle that when 3 phase AC supply is applied to stator of LEM then magnetic field which is linearly moving nature is induced. 

The moving magnetic field is cut by short circuited conductors and emfs are induced in them. Therefore currents flow through them. The currents interact with the moving magnetic field and electromagnetic forces are produced on conductors. 

Under the influence these forces, according to Lenz’s law, the conductors try to move in such way as to eliminate the induced currents. Hence the conductors move linearly within the magnetic field. Therefore, the rotor and the drive starts moving in linear way. As in this linear motion, there is no contribution of wheels so it is called as wheel less drive.