magnetic levitation

Magnetic Levitation

Levitation means to raise or float against the gravitational force. So, Magnetic Levitation, by its name is understood that a raise made using magnets or magnetic field. The train which runs using this principle is called as “Magnetic Levitation Trains” or “Maglev Trains”. These trains will float over a track called the guideway using the basic principles of magnets, replacing the steel wheel and track trains.

Concept

The basic concept of magnetism, likes poles repel and unlike poles attract, is the basic principle of Maglev Trains. The major difference between maglev train and conventional train is that maglev trains do not have any engine. Instead the train is propelled due to the magnetic filed created by the electrified coils in the walls of the guideway and track.

The electric current supplied to the coils in guideway walls are constantly alternating to change the polarity of the magnetized coil. This change in polarity is used to pull the train forward and push from backside.

Picture explanation

Step 1:
The North Pole at position 4 pulls the train front due to attraction of unlike poles and the North Pole at position 2 pushes the train front due to repulsion of like poles. South Pole also does the same. So the train moves forward.
Step 2:
While moving forward if the pole does not change, then it will push the train backward and there will be no motion experienced. So, at step 2 the polarity of the coils in the guided walls changes. By doing so the train is again pushed forward making a complete motion.

Types of MagLev Trains

There are mainly two types of Magnetic Levitation Trains. These types are differentiated by the system used to produce the electromagnetic field.
1. Electromagnetic Suspension (EMS)
2. Electrodynamic Suspension (EDS)

Electromagnetic Suspension (EMS)

German engineers developed this design, called Transrapid. This method uses conventional electromagnets mounted at the end of a pair of structures under train. The magnetized coil running along the track repels the large magnets on train’s undercarriage allowing the train to levitate to a height of 10mm with people onboard. This design needs constant monitoring and is adjusted by computers to prevent the train hitting the guideway track. The electromagnets mounted at the train’s undercarriage helps to levitate the train even when it’s not moving. Germany demonstrated that the Transrapid maglev train can reach a speed of 300 mph (480 kph) with people onboard.

Electrodynamic Suspension (EDS)

Japanese engineers are developing the Electrodynamic Suspension (EDS) design of maglev trains. These trains use super-cooled, superconducting electromagnets which can conduct electricity even after the supply has been shut off. By cooling the coils to certain temperature, the material used can be made to near the state of superconductivity. This saves power but the cooling system implemented is expensive. It can levitate about 4 to 6 inches and it uses rubber tires until they reach a liftoff speed of about 60 mph. These trains can attain more speed than EDS since the clearance from the track was more.

Advantages of Maglev Trains

1. Less physical resistance (except air resistance), so can attain great speed.
2. No burning of fossil fuels
3. Less or no pollution
4. As it is levitated, there will be no vibration