Magnetically Levitated Trains (MagLev) Ravi Kumar Sahni M.E 3 rd yr

The Maglev Train History In the 1960s in Britain Eric Laithwaite developed a functional maglev train. His maglev had 1.6 km of track and was in detail tested. His research was stopped in 1973 because lack of money and his progress was not enough. In the 1970s, Germany and Japan also began research and after some failures both nations developed mature technologies in the 1990’s………………………………… …..

What are MagLev trains? MagLev uses Electromagnetic Propulsion. Trains are thrust forward by positively and negatively charged magnets. The train floats on a cushion of air eliminating friction.

MagLev “Guideways” or Tracks Track repels magnets on undercarriage of train, sending the train forward. Train levitates between 1 and 10 cm above guideway.

How Transrapid Works Support System The electromagnets on the underside of the train pull it up to the ferromagnetic stators on the track and levitate the train. The magnets on the side keep the train from moving from side to side. A computer changes the amount of current to keep the train 1 cm from the track. This means there is no friction between the train and the track!

Propulsion System : Electrodynamic Propulsion is the basis of the movement in a Maglev system. The basic principle that electromagnetic propulsion follows is that “opposite poles attract each other and like poles repel each other”. This meaning that the north pole of a magnet will repel the north pole of a magnet while it attracts the south pole of a magnet. Likewise, the south pole of a magnet will attract the north pole and repel the south pole of a magnet. It is important to realize these three major components of this propulsion system. They are:- A large electrical power source Metal coils that line the entire guideway ·Guidance magnets used for alignment

MAGNETIC LEVITATION SYSTEM Magnetic levitation means “to rise and float in air”. The Maglev system is made possible by the use of electromagnets and magnetic fields. The basic principle behind Maglev is that if you put two magnets together in a certain way there will be a strong magnetic attraction and the two magnets will clamp together. This is called "attraction". If one of those magnets is flipped over then there will be a strong magnetic repulsion and the magnets will push each other apart. This is called "repulsion". On the basis of this principle, Magnetic Levitation is broken into two main types of suspension or levitation, Electromagnetic Suspension. Electrodynamic Suspension.

ELECTROMAGNETIC SUSPENSION SYSTEM This suspension uses conventional electromagnets located on structures attached to the underside of the train; these structures then wrap around a T-shaped guiderail. This guiderail is ferromagnetic, meaning it is made up of such metals as iron, nickel, and cobalt, and has very high magnetic permeability. The magnets on the train are then attracted towards this ferromagnetic guiderail when a “current runs through the guiderail and the electromagnets of the train are turned on”. This attraction lifts the car allowing it to levitate and move with a frictionless ride. “Vehicle levitation is analyzed via on board computer control units that sample and adjust the magnetic force of a series of onboard electromagnets as they are attracted to the guideway”.

ADVANTAGES OF E.M.S Train interlocks with the guiderail making it impossible to derail No contact between the train and its track. So power loss minimum Reduces the noise and maintenance of the system

ELECTRODYNAMIC SUSPENSION SYSTEM EDS uses superconducting magnets (SCM) located on the bottom of the train to levitate it off of the track. By using super cooled superconducting magnets, the electrical resistance in superconductors allows current to flow better and creates a greater magnetic field. The downside to using an EDS system is that it requires the SCMs to be at very cold temperatures, usually around 5 K (-268ºC) to get the best results and the least resistance in the coils. The Japanese Maglev, which is based on an EDS system, uses a cooling system of liquid nitrogen and helium.

Levitation The passing of the superconducting magnets by figure eight levitation coils on the side of the tract induces a current in the coils and creates a magnetic field. This pushes the train upward so that it can levitate 10 cm above the track. The train does not levitate until it reaches 50 mph, so it is equipped with retractable wheels.

Lateral Guidance When one side of the train nears the side of the guide way, the super conducting magnet on the train induces a repulsive force from the levitation coils on the side closer to the train and an attractive force from the coils on the farther side. This keeps the train in the center.

Levitation System’s Power Supply Batteries on the train power the system, and therefore it still functions without propulsion. The batteries can levitate the train for 30 minutes without any additional energy. Linear generators in the magnets on board the train use the motion of the train to recharge the batteries. Levitation system uses less power than the trains air conditioning.

BLOCK DIAGRAM FREQUENCY REFERENCE SIGNAL FOR SPEED CONTROL CONTROLLER TRACK THREE- PHASE POWER INPUT TRAIN WITH SPEED SENSOR

MagLev vs. Conventional Trains MagLev TrainsConventional Trains No Friction = Less Maintenance Routine Maintenance Needed No Engine = No fuel required Engine requires fossil fuels Speeds in excess of 300 mph Speeds up to 110 mph

ADVANTAGES Safety The trains are virtually impossible to derail because the train is wrapped around the track. Collisions between trains are unlikely because computers are controlling the trains movements. Earth Quake Proof Maintenance There is very little maintenance because there is no contact between the parts.

Comfort The ride is smooth while not accelerating.. Speed The train can travel at about 300 mph. (Acela can only go 150 mph) For trips of distances up to 500 miles its total travel time is equal to a planes (including check in time and travel to airport.) It can accelerate to 200 mph in 3 miles, so it is ideal for short jumps.

Noise Pollution The train makes little noise because it does not touch the track and it has no motor. Therefore, all noise comes from moving air. This sound is equivalent to the noise produced by city traffic.

Better for the Environment Less energy consumption because no rail- track friction Requires no fossil fuel which can harm the environment. Less noise pollution since the train never hits the track MagLev guide ways and trains take up less space than conventional trains

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