History
Samuel Earnshaw was the one to discover in 1839 that “a charged body placed in an electrostatic field cannot levitate at stable equilibrium under the influence of electric forces alone”. Likewise, due to limitations on permittivity, stable suspension or levitation cannot be achieved in a static magnetic field with a system of permanent magnets or fixed current electromagnets. Braunbeck’s extension (1939) states that a system of permanent magnets must also contain diamagnetic material or a superconductor in order to obtain stable, static magnetic levitation or suspension.
Emile Bachelet applied Earnshaw's theorem and the Braunbeck extension and stabilized magnetic force by controlling current intensity and turning on and off power to the electromagnets at desired frequencies. He was awarded a patent in March 1912 for his “levitating transmitting apparatus” (patent no. 1,020,942). His invention was first intended to be applied to smaller mail carrying systems but the potential application to larger train-like vehicles is certainly apparent.
In 1934 Hermann Kemper was the one to apply Bachelet’s concept to the large scale, calling it “monorail vehicle with no wheels attached.” He obtained Reich Patent number 643316 for his invention and is also considered by many to be the inventor of maglev.
In 1979 the Transrapid electromagnetically suspended train carried passengers for a few months as a demonstration on a 908 m track in Hamburg for the first International Transportation Exhibition (IVA 79).
The first commercial Maglev train for routine service was opened in Birmingham, England in 1984, using electromagnetic suspension, and a linear induction motor for propulsion.
Read more about this topic: Electromagnetic Suspension
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