29751954 Magnetic Levitation

7/29/2019 29751954 Magnetic Levitation

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MAGNETIC LEVITATIONDRIVING WITHOUT WHEELS

AJAY KUMAR GARG ENGINEERING COLLEGE,GZB

BY

PRABHAT KUMAR PATEL
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MAGNETIC LEVITATION

It is a method by which anobject is suspended with no supportother than magnetic field.

It is also known as magnetic

suspension.The highest recorded speed of a

Maglev train is 581 kilometers perhour (361 mph), achieved in Japan
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Maglev tech is a relatively newtransportation tech in which noncontacting vehicles travel safely at speedsof 250 to 300mph or higher.

The forces acting on an object in anycombination of gravitational, electrostatic,and magneto static fields will make theobject's position unstable.

It is possible to levitate superconductorsand other diamagnetic materials, whichmagnetize in the opposite sense to amagnetic field in which they are placed.

As Superconductors are perfectdiamagnets and when placed in anexternal magnetic field expel the fieldlines from their interiors


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PRINCIPLE OF OPERATION

Imagine that two barmagnets are suspendedone above the other withlike poles directly above

and below each other.Any effort to bring thesetwo magnets into contactwith each other will have

to overcome the force ofrepulsion that existsbetween two likemagnetic poles.


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The repulsion of superconducting magnets and electromagnets inthe track keeps a maglev train suspended above the track. Byvarying the strength and polarity of the track electromagnets, the

train can be driven forward.


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Lateral Guidance

When one side of the trainnears the side of the guideway, the super conducting

magnet on the train inducesa repulsive force from thelevitation coils on the sidecloser to the train and an

attractive force from the coilson the farther side. Thiskeeps the train in the center.


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The magnetized coilrunning along the track, calleda guideway, repels the largemagnets on the train'sundercarriage, allowing the

train to levitate between 0.39and 3.93 inches (1 to 10 cm)above the guideway.

Power is supplied to

the coils within the guidewaywalls to create a unique systemof magnetic fields that pull andpush the train along the

guideway.

MAGLEV GUIDE TRACK


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LEVITATIONLevitation is the process by which an

object is suspended against gravity in a stableposition.

First thing a maglev system must do is get

off the ground, and then stay suspended off theground.


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Electromagnetic Suspension


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In the EMS-attractivesystem, the electromagnets

which do the work oflevitation are attached onthe top side of a casingthat extends below andthen curves back up to therail that is in the center ofthe track.

The gap between thebottom of the vehicle andthe rail is only 3/8"


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Electrodynamic Suspension

In the EDS-repulsive system, thesuperconducting magnets (SCMs),which do the levitating of thevehicle, are at the bottom of thevehicle, but above the track.

The magnetic field of thesuperconducting magnets aboard

the maglev vehicle induces aneddy current in the guideway.


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Choice of linear induction motorA linear electric motor (LEM)

is a mechanism whichconverts electrical energydirectly into linear motionwithout employing any

intervening rotarycomponents.

Linear Induction Motor (LIM)is basically a rotating squirrel

cage induction motor openedout flat. Instead of producingrotary torque from acylindrical machine it

produces linear force from aflat one.


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Linear Synchronous Motor

LSM generate

propulsive force byrunning currentthrough a stator,which creates an

electro-magnetic field.This electro-magnetic

field interacts with aset of permanent

magnets on a vehicleto create thrust.


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The permanent magnets serve as the motorsecondary, equivalent to a rotor in conventionalmotors enabling linear motion.

The vehicle is propelled by the moving electro-magnetic field, traveling along as electric current is

applied to the stator beneath the vehicle.

The vehicles movement is regulated by asophisticated control system incorporating state-

of-the-art position sensing technology.


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Linear induction motor (LIM)in magnetic levitation

The High Speed SurfaceTransport (HSST) system ispropelled by linear induction

motor.The HSST levitation system

uses ordinary electromagnets

that exerts an attractive forceand levitate the vehicle.


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The electromagnetsare attached to the

car, but arepositioned facingthe under side of theguide way's steel

rails. They providean attractive forcefrom brlow,levitatingthe car.


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Characteristics of LIM

In most vehicular propulsionsystems, provision must be madefor increasing the power when

the demand increases.Whenever more power is needed,

the moving magnet begins to lagfurther behind the stationary one;

this results in an immediateincrease in thrust. No separatecontrol is needed


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Benefits of Magnetic Levitated Transportation

system

Power of the maglev motor is dependent on the localconditions.

Maglev uses 30% less energy than a high-speed traintraveling at the same speed.

Operating costs of a maglev system are approximately halfthat of conventional long-distance railroads. Maglev is about 20 times safer than airplanes, 250 times

safer than conventional railroads, and 700 times safer thanautomobile travel.

Despite the speeds up to 500 km/hour, passengers canmove about freely in the vehicles Easy maintenance, no friction and less noise pollution.


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Noise Pollution

The train makes littlenoise because it does not

touch the track and it hasno motor. Therefore, allnoise comes from movingair.

This sound is equivalent

to the noise produced bycity traffic.

Magnetic Field

The magnetic fieldcreated is low, thereforethere are no adverseeffects.


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CURRENT PROJECTS

Germany and Japan have been the pioneering countriesin MagLev research. Currently operational systems includeTransrapid (Germany) and High Speed Surface Transport(Japan). There are several other projects under scrutiny such

as the Swiss Metro, Seraphim and Inductrack. All have to dowith personal rapid transit.

NASA plans to use magnetic levitation for launching of

space vehicles into low earth orbit.Boeing is pursuingresearch in MagLev to provide a Hypersonic Ground TestFacility for the Air Force. The mining industry will alsobenefit from MagLev. There are probably many more

undiscovered applications!


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CONCLUSION

The Maglev Train: Research on thisdream train has been going on for the last30 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. Maintenancecosts decrease. Low noise emission andvibrations at all speeds.

29751954 Magnetic Levitation

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