MAGLEV TRAIN Guideway To The New Journey Network Analysis Presentation Submitted by- Harshit Goel Ishu Tiwari Sukalp Gupta Sharad Srivastava Network Analysis Presentation

What is Maglev/Magnetic levitation? The term "maglev" refers not only to the vehicles, but to the railway system as well, specifically designed for magnetic levitation and propulsion. Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields. Magnetic pressure is used to counteract the effects of the gravitational and any other accelerations. Using only ferromagnetic or paramagnetic materials it is impossible to stably levitate against gravity; however, servomechanisms, the use of  diamagnetic materials, superconduction, or systems involving eddy currents allow to achieve that.

Maglev Trains A Maglev Train is a train that travels with out touching the 'tracks'. It floats above the surface with magnetic levitation. The first an only high speed commercial magnetic levitation train in operation right now is the Shanghai Maglev Train in China. It is very cool, but it costs so much to build and run it is not really viable technology right now.

Basic Principle of maglev Trains Maglev trains have to perform following functions to operate in high speeds Levitation Propulsion Lateral Guidance

Technology There are two particularly notable types of maglev technology: Electrodynamic suspension (EDS) uses superconducting electromagnets or strong permanent magnets which create a magnetic field that induces currents in nearby metallic conductors when there is relative movement which pushes and pulls the train towards the designed levitation position on the guide way. For electromagnetic suspension (EMS), electronically controlled electromagnets in the train attract it to a magnetically conductive (usually steel) track.

Electrodynamic Suspension Electrodynamic suspension (EDS) is a form of magnetic levitation in which there are superconductors which are exposed to time-varying Magnetic fields. This induces eddy currents in the conductors that creates a repulsive magnetic field which holds the two objects apart. EDS is used for maglev trains, such as the Japanese SC Maglev.

Levitation The passing of the superconducting magnets on train by the levitation coils on both sides of the track 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.

Propulsion The propulsion coils located on the sidewalls on both sides of the guideway are energized by a three-phase alternating current from a substation, creating a shifting magnetic field on the guideway. The on-board superconducting magnets are attracted and pushed by the shifting field, propelling the Maglev vehicle. Braking is accomplished by sending an alternating current in the reverse direction so that it is slowed by attractive and repulsive forces.

Lateral Guidance When one side of the train nears the side of the guideway, 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.

Electromagnetic Suspension Electromagnetic Suspension (EMS) is the magnetic levitation of an object achieved by constantly altering the strength of a magnetic field produced by Electromagnets using a feedback loop. In most cases the levitation effect is mostly due to permanent magnets as they don't have any power dissipation, with electromagnets only used to stabilize the effect.

Levitation In the EMS-attractive system, the electromagnets do the work of levitation and are attached on the top side of a casing that extends below and then curves back up to the rail that is in the center of the track.

The rail, which is in the shape of an inverted T, is a ferromagnetic rail. When a current is passed through it, and the electromagnet switched on, there is attraction, and the levitation electromagnets, which are below the rail, raise up to meet the rail. The car levitates.

Propulsion A linear electric motor (LEM) is a mechanism which converts electrical energy directly into linear motion without employing any intervening rotary components Linear Induction Motor (LIM) is basically a rotating squirrel cage induction motor opened out flat Instead of producing rotary torque from a cylindrical machine it produces linear force from a flat one. LIM thrusts vary from just a few to thousands of Newtons , depending mainly on the size and rating Speeds vary from zero to many meters per second and are determined by design and supply frequency

A conventional rotary synchronous motor , is made up of two rings of alternating north and south magnetic poles. The outer ring (the stator) is stationary, while the inner one (the rotor) is free to rotate about a shaft. The polarity of the magnets on one (either) of these rings is fixed; this element is known as the field. The magnets of the other ring, the armature, change their polarity in response to an applied alternating current.

Attractive forces between unlike magnetic poles pull each element of the rotor toward the corresponding element of the stator. Just as the two poles are coming into alignment, the polarity of the armature magnets is reversed, resulting in a repulsive force that keeps the motor turning in the same direction. The armature poles are then reversed again, and the motor turns at a constant speed in synchronism with the alternating current which causes the change in polarity

Lateral Guidance The levitation magnets and rail are both U shaped(with rail being an inverted U). The mouths of U face one another. This configuration ensures that when ever a levitational force is exerted, a lateral guidance force occurs as well. If the electromagnet starts to shift laterally from the center of the rail, the lateral guidance force is exerted in proportion to the extent of the shift, bringing the electromagnet back into alignment.

Advantages of Magnetic Levitated Transportation System Maglev uses 30% less energy than a high-speed train traveling at the same speed (1/3 more power for the same amount of energy). The operating costs of a maglev system are approximately half that of conventional long-distance railroads. Research has shown that the maglev is about 20 times safer than airplanes, 250 times safer than conventional railroads, and 700 times safer than automobile travel. Maglev vehicle carries no fuel to increase fire hazard The materials used to construct maglev vehicles are non-combustible, poor penetration transmitters of heat, and able to withstand fire.

Conclusion The MagLev Train: Research on this ‘dream train' has been going on for the last 30 odd years in various parts of the world. The chief advantages of this type of train are: Non-contact and non-wearing propulsion, independent of friction, no mechanical components like wheel, axle. Maintenance costs decrease The MagLev offers a cheap, efficient alternative to the current rail system. A country like India could benefit very much if this were implemented here. Further possible applications need to be explored

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