Maglev TrainsChethan R2nd Sem, Mechanical Engineering, GECH

ContentsIntroductionFast factsHow it worksMaglev TechnologyAdvantages Disadvantages

Introduction

Magnetic levitation is a method by which an object is suspended with no support other than magnetic fields.

Magnetic force is used to counteract the effects of the gravity.

IntroductionIn 1922, a German engineer Hermann Kemper came with an idea of maglev trains. Maglev trains move more smoothly and more quietly than wheeled mass transit systems.

Fast FactsA Japanese maglev train has broken its own world speed record, hitting 603km/h in a test run near mount Fuji on April 21st 2015.

Shanghais maglev train is currently the only commercial maglev train in operation in the world.

It cost $ 1.2 billion to build.

How it worksA maglev train floats about 10mm above the guide way on a magnetic field.It is propelled by the guide way itself rather than an onboard engine by changing magnetic fields.Once the train is pulled into the section the magnetism switches so that the train is pulled on again.The electro-magnets run the length of the guide way.

Maglev technologyThere are two primary types of maglev technology:Electromagnetic suspension(EMS)Electrodynamic suspension(EDS)

Electromagnetic suspensionIn current EMS systems, the train levitates above a steel rail while electromagnets, attached to the train are oriented toward the rail from below.The electromagnets use feedback control to maintain a train at a constant distance from the track.

Electrodynamic suspension

In electrodynamic suspension, both the rail and the train exert a magnetic field, and the train is levitated by the repulsive force between these magnetic fields.The magnetic field in the train is produced by either electromagnets or by an array of permanent magnets.The repulsive force in the track is created by an induced magnetic field in wires or other conducting strips in the track.

Electrodynamic suspension At slow speeds, the current induced in these coils and the resultant magnetic flux is not large enough to support the weight of the train.For this reason the train must have wheels to support the train until it reaches speed that can sustain levitation.The propulsion coils that exert a force on the train are effectively a linear motor.

Advantages A maglev is way faster than usual bullet train. Due to its lack of wheels, maglevs are quieter than normal trains.Maglevs use 30% less energy than normal trains.In theory, a maglev and its track would require very little maintenance since the train never touches the track, there is virtually no wear and tear.

DisadvantagesThe maglevs track is much more expensive than railroad tracks.Larger trains cars are tougher to levitate and require quite a bit more energy, making them less efficient.While the maglev can be safer overall, any infrequent accidents that do occur are likely to be more catastrophic due to the elevated guide ways and incredible speeds.

THANK YOU