Linear motors are electric induction motors that produce motion in a straight line rather than rotational motion. In a traditional electric motor, the rotor (rotating part) spins inside the stator (static part); in a linear motor, the stator is unwrapped and laid out flat and the “rotor” moves past it in a straight line. Linear motors often use superconducting magnets, which are cooled to low temperatures to reduce power consumption.
Linear induction motor
German engineers first produced a working prototype in 1971 and developed the Transrapid system a year later. Strictly speaking, the Transrapid uses magnetic attraction rather than the magnetic repulsion normally associated with maglev: the copper magnets are fixed to a “skirt” that runs underneath, and is attracted up toward, the steel track. With considerable support from the German government, Transrapid has been progressively refined into a viable train that can reach speeds of up to 433 kph (271 mph). Decades of investment and development finally paid off in 2004, when Transrapid opened the world’s first (and so far only) high-speed system, the Shanghai Maglev Train (SMT), in China. Although it currently operates on only a short section of track (a mere 31km or 19 miles long), there have been several plans to extend it, though they have repeatedly been shelved.