AMITY UNIVERSITY

Department of Mechanical & Automation Engineering

Project Report

MAGNETIC LEVIATION

Program: Mechanical & Automation Engineering

Prepared for:

Prof. V. VERMA

Names Student ID Signature*

ANKUR PANDEY A7605408058

SHIV PRASHANT A7605408064

ANKUR DWIVEDI A7605408051

RAHUL AWASTHI A76054080

ASHISH SINGH A7604080

JITESH KESHWANI A760540805

GAURAV MAKHIJANI A760540805

.

PERMANENT MAGNETIC LIFTER

Usage:Widely used in lifting and transporting flat and round steel loads , without the need forslings, clamps, or other holding devices, no damage to the surface of lifted goods,saving the lifting time and optimizing the piled up area.Features:1）Without power, No risk in the condition of no electrical source .2）Use high-energy Permanent magnetic material to be smaller volume .3) A great concentration of power with a safety factor 1:3.5 on the suggested load.4) Optimized magnetic circuit together with appearance design made the structure ofthe product simple and firm ,even with a large air gap.5) Special handle-operating switch with safety bottom6) Type V through at the bottom of the holding face ; can lift round stick and steelpanel. Type choice:Please choose the related type according to the thickness ,weight of the lifted objects,material character, magnetic area , surface finish ，the space between it and magneticlift, or the weight balance condition of the lifted objects.Please refer to the application and safety notes for each respective lifter for safeoperation.

S.SHARANAPPA & K.DINESHsharantillu@yahoo.com dinesh_withyou@yahoo.co.in

ABSTRACTMAGNETIC LEVITATION –It is use of magnetic fields to levitate a metallic object .Bymanipulating magnetic fields and controlling their forces an object can be levitated.Because of the growing need for quicker and more efficient methods for movingpeople and goods, researchers have turned to a new technique, one usingelectromagnetic rails and trains. This rail system is referred to as magnetic levitation,or maglev. Maglev is a generic term for any transportation system in which vehiclesare suspended and guided by magnetic forces. Instead of engines, maglev vehicles useelectromagnetism to levitate (raise) and propel the vehicle. Alternating currentcreates a magnetic field that pushes and pulls the vehicle which weighs almost about1500 tonnes and keeps it above the support structure, called a guide way. Anothermajor application of magnetic levitation is ELEKTROMAG. "ELEKTROMAG"-- MagneticSheet Floaters have been designed for easy handling of stacked sheets in production jobs.MAGNETIC LEVITATION:INTRODUCTION:The word levitation is derived from a latin word “LEVIS”,which means light. Magneticlevitation is the use of magnetic fields to levitate a metallic object. By manipulating magneticfields and controlling their forces an object can be levitated. When the like poles of twopermanent magnets come near each other, they produce a mutually repulsing force that growsstronger as the distance between the poles diminishes. When the unlike poles of two permanentmagnets are brought close to each other, they produce a mutually attractive force that growsstronger as the distance between them diminish A levitation system designed around theattractive force between unlike poles would require a perfect balance between the attractivemagnetic force and the suspended weight In the absence of a perfect lift and weight force profile,the conveyance would either be pulled up toward the magnets or would fall. This simpleillustration of magnetic levitation shows that the force of gravity can be counterbalanced bymagnetic force.

There are two ways of levitations,1.Active 2. Passive.In an active levitation system, electromagnets are coupled to amplifiers that receive signals fromcontrollers. These controllers process signals from sensors that change the magnetic force tomeet the needs of the magnetic system.Passive magnetic levitation systems are impractical without a stabilizing ingredient.Diamagnetic levitation can be used to add stability to passive levitation systems. Thecombination of passive and diamagnetic levitation is a functional approach to many magneticlevitation application.Magnetic levitation is used in transportation particularly in monorails,and in levitating displays.Magnetic bearings have been used in pumps, compressors, steam turbines, gas turbines, motors,and centrifuges, but these complex applications require electromagnets, sensors, and controlsystems.

Major applications of magnetic levitation are:1. Transportation: Maglev trains.2. Moving of metallic objects in steel industry: Magnetic floaters.3. Military applications:Rail-gun.MAGLEV:Powerful electro magnets are used to develop high-speed trains called maglevtrains. These will float over a guideway using the basic principles of magnets to replace the oldsteel wheel and track trains.Magnetic levitation (maglev) is a relatively new transportation technology in which noncontactingvehicles travel safely at speeds of 250 to 300 miles-per-hour or higher while suspended, guided,and propelled above a guideway by magnetic fields. The guideway is the physical structure alongwhich maglev vehicles are levitated. Various guideway configurations, e.g., T-shaped, U-shaped,Y-shaped, and box-beam, made of steel, concrete, or aluminum, have been proposed.A super high-speed transport system with a non-adhesive drive system that is independent ofwheel-and-rail frictional forces has been a long-standing dream of railway engineers.Maglev, a combination of superconducting magnets and linear motor technology, realizessuper high-speed running, safety, reliability, low environmental impact and minimummaintenance.

Principle of MaglevMaglev is a system in which the vehicle runs levitated from the guideway (corresponding to therail tracks of conventional railways) by using electromagnetic forces between superconducting

magnets on board the vehicle and coils on the ground. The following is a general explanation ofthe principle of Maglev.

Principle of magnetic levitationThe "8" figured levitation coils are installed onthe sidewalls of the guideway. When the onboardsuperconducting magnets pass at a highspeed about several centimeters below the centerof these coils, an electric current is inducedwithin the coils, which then act aselectromagnets temporarily. As a result, thereare forces which push the superconductingmagnet upwards and ones which pull themupwards simultaneously, thereby levitating theMaglev vehicle.

Principle of lateral guidanceThe levitation coils facing each other areconnected under the guideway, constituting aloop. When a running Maglev vehicle, that is asuperconducting magnet, displaces laterally, anelectric current is induced in the loop, resultingin a repulsive force acting on the levitation coilsof the side near the car and an attractive forceacting on the levitation coils of the side fartherapart from the car. Thus, a running car is alwayslocated at the center of the guideway.

Principle of propulsionA repulsive force and an attractive force inducedbetween the magnets are used to propel thevehicle (superconducting magnet). Thepropulsion coils located on the sidewalls on bothsides of the guideway are energized by a threephasealternating current from a substation,creating a shifting magnetic field on theguideway. The on-board superconductingmagnets are attracted and pushed by the shiftingfield, propelling the Maglev vehicle.Figure 1 depicts the three primary functions basic to maglev technology: (1) levitation orsuspension; (2) propulsion; and (3) guidance. In most current designs, magnetic forces are usedto perform all three functions, although a nonmagnetic source of propulsion could be used. Noconsensus exists on an optimum design to perform each of the primary functions.Suspension SystemsThe two principal means of levitation are illustrated in Figures 2 and 3. Electromagnetic

suspension (EMS) is an attractive force levitation system whereby electromagnets on the vehicleinteract with and are attracted to ferromagnetic rails on the guideway. EMS was made practicalby advances in electronic control systems that maintain the air gap between vehicle andguideway, thus preventing contact.Variations in payload weight, dynamic loads, and guideway irregularities are compensated for bychanging the magnetic field in response to vehicle/guideway air gap measurements.Electrodynamic suspension (EDS) employs magnets on the moving vehicle to induce currents inthe guideway. Resulting repulsive force produces inherently stable vehicle support and guidancebecause the magnetic repulsion increases as the vehicle/guideway gap decreases. However, thevehicle must be equipped with wheels or other forms of support for "takeoff" and "landing"because the EDS will not levitate at speeds below approximately 25 mph. EDS has progressedwith advances in cryogenics and superconducting magnet technology.Figure 2 and Figure 3Propulsion Systems "Long-stator" propulsion using an electrically powered linear motorwinding in the guideway appears to be the favored option for high-speed maglev systems. It isalso the most expensive because of higher guideway construction costs."Short-stator" propulsion uses a linear induction motor (LIM) winding onboard and a passiveguideway. While short-stator propulsion reduces guideway costs, the LIM is heavy and reducesvehicle payload capacity, resulting in higher operating costs and lower revenue potentialcompared to the long-stator propulsion. A third alternative is a nonmagnetic energy source (gasturbine or turboprop) but this, too, results in a heavy vehicle and reduced operating efficiency.Guidance SystemsGuidance or steering refers to the sideward forces that are required to make the vehicle followthe guideway. The necessary forces are supplied in an exactly analogous fashion to thesuspension forces, either attractive or repulsive. The same magnets on board the vehicle, whichsupply lift, can be used concurrently for guidance or separate guidance magnets can be used.You can easily create a small electromagnet yourself by connecting the ends of a copper wire tothe positive and negative ends of an AA, C or D-cell battery. This creates a small magnetic field.

If you disconnect either end of the wire from the battery, the magnetic field is taken away.The magnetic field created in this wire-and-battery experiment is the simple idea behind amaglev train rail system. There are three components to this system:• A large electrical power source• Metal coils lining a guideway or track• Large guidance magnets attached to the underside of the trainThe big difference between a maglev train and a conventional train is that maglev trains do nothave an engine -- at least not the kind of engine used to pull typical train cars along steel tracks.The engine for maglev trains is rather inconspicuous. Instead of using fossil fuels, the magneticfield created by the electrified coils in the guideway walls and the track combine to propel thetrain.Photos courtesy Railway Technical Research InstituteAbove is an image of the guideway for the Yamanashi maglev test line in Japan.Below is an illustration that shows how the guideway works.

The magnetized coil running along the track, called a guideway, repels the large magnets on thetrain's undercarriage, allowing the train to levitate between 0.39 and 3.93 inches (1 to 10 cm)above the guideway. Once the train is levitated, power is supplied to the coils within theguideway walls to create a unique system of magnetic fields that pull and push the train along theguideway. The electric current supplied to the coils in the guideway walls is constantlyalternating to change the polarity of the magnetized coils. This change in polarity causes themagnetic field in front of the train to pull the vehicle forward, while the magnetic field behindthe train adds more forward thrust.Maglev trains float on a cushion of air, eliminating friction. This lack of friction and the trains'aerodynamic designs allow these trains to reach unprecedented ground transportation speeds ofmore than 310 mph (500 kph), or twice as fast as Amtrak's fastest commuter train.Japanesse MLU-002 maglev train. The tracks enclose it on the sides and underneath

How fast can they go?On test runs maglev trains have been able to exeed 300mph. In Germany the top speed of amaglev train was 312mph and Japan's maglev trains reached 323mph in 1979 shattering therecord books. With advances on maglev trains, people say it will be able to go 600mph to1000mph in the future. If maglev trains succeed they will revolutionize the way we getaround and dramatically reduce travel time.

ADVANTAGES OF MAGLEV OVER CONVENTIONAL TRAINS :

Conventional trains use an engine where as maglev vehicles instead of engines useelectro magnetism to levitate(raise) and propel the vehicle.

Instead of using fossil fuels, the magnetic field created by the electrified coils in theguideway walls and the track combine to propel the train.

Using a magnet's repelling force to float above magnets in the guideway, the trains aren'thampered by friction where as, Conventional trains are noisy due to the friction betweentheir wheels and the steel rails, but maglev trains are much quieter.These maglev trains are uncomparablely faster than normal conventional trains.

Moreover as these maglev trains work using electromagnetic induction using electricitythese are pollution free.

IN COMPARISON WITH TGV :

TGV-train de grande vitese,which means jets on land.

Today, the fastest train in regular passenger service is France's TGV. Itactually topped out during a speed run at 319 mph. Japan has ademonstration maglev train that went 31 mph faster than that, but notwithout problems.

While the TGV can reach such speeds, it does so by using tremendousamounts of power, and the noise is incredible. The TGV normally travelscloser to 150 mph.

Maglev trains don't have such problems.Using a magnet's repelling force to float above magnets in the guideway,the trains aren't hampered by friction.

Are Maglev trains safe?Maglev trains have proven to be exceptionally safe, quiet, and fast. Because there's no frictionwith the ground, maglev trains are much more quiet than trucks and automobiles. Theonly sound caused by the trains is the whoosh as the train goes by from the air friction.Farmers in Germany who have trains running over their fields, when asked about how thefeel about the trains running through their farm replied "We don't even know it's there".Cows don't even lift their heads when trains come through at 250mph. Maglev trains arealso almost accident free. They are above any obstacles on the ground and are enclosed inor around the track. Also the propoltion system caused by the magnetic fields disallowstrains to come to close to other trains on the track.WHY MAGLEV???????

Permits speed of vehicles of 250 to 300MPH and even higher.

High reliability and less susceptible to congestion and weather conditions than air orhighway travel.

Maglev is petroleum independent with respect to air and auto because of maglev beingelectrically powered.

Maglev is less polluting as fossil fuels are not used.

Maglev has higher capacity than air travel.

High safety and more convenient mode of transport.INTRODUCTION"ELEKTROMAG" Magnetic Sheet Floaters have been designed for easyhandling of stacked sheets in production jobs, It cuts costs on any job where steelsheets are handled in production jobs. They help boost press and press brakeproduction by eliminating the need to fumble with thin oily sheets. The steelsheets can be of any length,width or shape. Everlasting Powerful PermanentMagnet Sheet Floaters reduce operating cost.HOW IT WORKSA Sheet Floaters is positionedagainst the stack of steelsheets. The magnetic field passesin the steel sheets and they becomemagnetised in the area touching thesheet floater. As a result,the sheetsnear the top of the stack separate asthere is no load on the top sheet.When the topmost sheet is removed the next lower sheet automaticallymoves up. This action repeats until all sheets havebeen removed.Sheet Floaters may be used singly,in pairs or even in greater numbers depending uponjob requirements. Floating is accomplished by placing two or more units in positionwhich cause the entire top sheet to magnetically float over the others. Separation isachieved by using one unit at an edge or corner of the sheet.APPLICATIONThe Sheet Floaters can be used for heavy andlight gauges, large and small sheets, high andlow stacks, dry and oily sheets, irregular andround shapes, polished, painted or printedsheets. It can best be used for protection ofpolished, painted and furnished surfaces fromscratches.CONSTRUCTIONPowerful Permanent Magnets are housed in an all-welded steel housing. Mounting holes areprovided for fixing the floaters at any position. A handle is provided for easy shifting fromone job to another.

RANGE AND SIZES"ELEKTROMAG" offers the widest range of strengths necessary for different thickness andfor various sizes and shapes of material. Quotation can be submitted on receipt of thefollowing information:1. Gauge2. stack height3. shape4. size of materialthat needs to be handled on Sheet Floater. In fact there is a SheetFloater for every job.ADVANTAGES OF PERMANENT MAGNETIC SHEET FLOATERS

Save labour

Eliminate accidents

Reduce handling costs

CONCLUSIONThe future of magnetic levitation

Magnetic levitation is a phenomena that is likely to have considerable potential in thefuture. Particularly through the use of superconductive levitation.

A new idea for magentic levitation is in the use of storage of energy. Very basically ituses a rotating ring (flywheel) that stores (kinetic) moving energy which can be 'extracted'

MAGLEVMagnetic LevitationThe following paper was submitted and presented by me and my colleague in2002 during our Engineering Degree Course.Maglev is a technology which uses magnetic forces to suspend vehicles in air,hence eliminating friction. This allows vehicles to achieve very high speeds whichcan revolutionize the ground transportation. The technology is environmentfriendly but is yet in development stage.

2002Ashutosh AgrawalEmail: aagrawal.ie@gmail.comBlog: www.frontiers2explore.blogspot.comLinkedIn: www.linkedin.com/in/itsmeashu/2

MAGLEV:A NEW PROMISEBy:

Ashutosh Agrawal Anil Kumar SoniB.Tech, final year, B.Tech, final year,Mechanical Engg. Mechanical Engg.Kamla Nehru Institute of Technology, Sultanpur3

CONTENTS1. Abstract2. Introduction3. Levitation and Guidance Systems4. Propulsion System5. Guideway Configurations6. Maglev Transportation7. Maglev Launch System8. Conclusion9. References4

ABSTRACTMagnetic Levitation is an advanced technology known as Maglev in short. In this magneticforces lift, propel and guide a vehicle few centimeters above a guideway using magneticforces. The physical contact between vehicle and guideway is eliminated and permits cruisingspeeds in range of 500 km/h. The levitation and guidance is achieved by either magneticattraction ( EMS - Electro Magnetic Suspension ) or repulsion ( EDS - Electro DynamicSuspension ). The propulsion is achieved by linear motor of either ‘long stator’ or ‘shortstator’.Because of its high speed, Maglev may be able to offer competitive trip-time savings intransportation. Many feasible concepts of Maglev transportation like Skytran (for intracitytransportation), autoshuttle, transrapid etc have been developed and so also the variouspossible configurations of the guideways like ‘Y’, ‘U’, ‘T’ and Box beam.The capability of Maglev of controlled lift of thousands of pounds into the air and highacceleration has ushered it into area of space vehicle launch systems.The paper focuses on the technical aspects of Maglev that make this ‘flying in air’phenomenon possible and its profitable applications in transportation and space launch.5INTRODUCTION‘Trains that fly in air’, has fascinated many, but only a few know the magnificent yet simpleprinciple behind it. From long ago magnetic forces has been known as capable of suspendingferromagnetic particles in air. But it was at the turn of 20th century, the concept ofmagnetically levitated trains was first identified by two Americans, Robert Goddard andEmile Bachelet1. By the 1930’s Germany’s Hermann Kemper demonstrated the concept andin 1968 Americans James R. Powell and Gordon T. Danby were granted a patent on theirdesign of Maglev train1.A Maglev train is levitated (i.e. lifted), guided and propelled by magnetic fields a few

centimeters above the guideway, completely eliminating the physical contact between trainand guideway and enabling the speed up to 500km/h1.Over the past two decades, several countries including Germany, Japan and America haveconducted R&D programs in Maglev technology. Germany and Japan have invested over$1billion each to develop and demonstrate Maglev technology for High Speed GroundTransportation (HSGT) 1.Maglevs has expanded its area of application with NASA experimenting on the use of Maglevfor the cheaper launches of spacecrafts.LEVITATION AND GUIDANCE SYSTEMSAs shown in the fig.[1] levitation implies vertical support and guidance implies lateral supportto ensure that train does not run off the track. Same principle is employed for both supportand guidance.There are two principal means of both guidance and levitation. Attractive force system technically known as Electro Magnetic Suspension or EMS. Repulsive force system technically known as Electro Dynamic Suspension or EDS.

Electro Magnetic Suspension: In this electromagnets are attracted to ferromagnetic rails onthe guideway.6In the figure below the bar in blue colour is the guiderail and the one in red is electromagneton underside of the train.Variations in payload weight, dynamic loads and guideway irregularities are compensated forby changing the magnetic field in response to air gap measurements.Electro Dynamic Suspension: In this the magnets on the moving vehicle induce currents inthe induction coils of guideway as it passes over it. The resulting repulsive force suspends thevehicle in air. This system is inherently stable for both support and guidance becausemagnetic repulsion increases as the air gap decreases.However this system requires speed approx. upto 40km/h1 to levitate the vehicle. So thevehicle must be equipped with some support like wheels for speed below the 40km/h limit.This flaw as it may be seen is an advantage as it provides fail safe security in case if electricaldrive systems fail. The vehicle will be still levitated at speeds above the 40km/h and willslowly touch down the rails as speed will drop. In case of EMS system if onboard electricalsystem were to fail then vehicle will touch down at very moment at high speed of 500km/hand the result can be catastrophic.The induction coils that can be used are of two types: Simple single coil of shape ‘_’. ‘8’ shaped coil. The system is called null flux system and is worth discussing.

Drift between the rails and levitation magnets caused by wind or whenthe train rounds a curve.The gap widens between rail and track because of shortage of magnetic

force.The widening gap is sensed by gap sensors and the current is increased inleviatation magnets to increase the magnetic attraction till train comesback directly above the guide rails.7Null Flux System: In this system induction coils are wound as figure ‘8’. These coils aremounted on sidewalls of guideway.If vehicle’s magnetic field passes directly through centre of the ‘8’ shaped coil, the net flux iszero. But if field is slightly below their centre, electric current is induced within the coilswhich then act as electromagnets temporarily. The result is a repulsive force in lower half ofthe coil pushing it upward and attractive force in upper half of the coil pulling it upward. Bothact simultaneously to levitate the vehicle. Please refer fig.[2].There are currently two choices of magnets used on the vehicle in EDS: Superconducting magnets: The electrical resistivity of a superconducting material

becomes zero below a certain critical temperature. The current flows in the materialwithout any loss. So in a superconducting solenoid large current will keep circulating forlong periods. A superconducting magnet require small space, less material and producemagnetic field upto 5-10 T. Eg: TcYbaCuO, critical temp:77K5. Permanent magnets: the pemanent magnets used are that of Ne-Fe-B (Neodymium,

Iron& Boron) which are arranged in Halbach array4 (invented by Klaus Halbach).Halbach array: In this permanent magnets are arranged in alternate vertical andhorizontal pattern so that the magnetic-field lines reinforce one another below the arraybut cancel one another above it. Refer fig.[3].When moving, the magnets induce current in the track's circuits(‘_’ shaped coil), whichproduces an electromagnetic field that repels the array, thus levitating the train car.Halbach arrays can also provide lateral stability if they are deployed alongside the track'scircuits. Refer fig.[4].PROPULSION SYSTEMThere are two alternatives for propulsion:Non-magnetic energy source: gas turbine or turboprop can be used for the propulsion but thisresults in a heavy vehicle and reduced operating efficiency.Magnetic energy source: It employs the principle of linear motor for the propulsion.8A repulsive force and an attractive force induced between the magnets are used to propel thevehicle. The propulsion coils located on the sidewalls on both sides of the guideway areenergized by a three-phase alternating current from a substation, creating a shifting magneticfield on the guideway. The on-board magnets are attracted and pushed by the shifting field,propelling the Maglev vehicleThere are two possible cnfigurations of linear motor:Long Stator: ‘Long Stator’ propulsion uses an elctrically powered linear motor winding inthe guideway.Short Stator: In this the motor winding is on the vehicle and the guideway is passive.Of the two the Long Stator propulsion is having high initial cost but it has high payload

capacity and lower operating cost and studies indicate it to be a favoured option.The drive coils in long stator can be interspersed among the track's levitating circuits. Anarray of substations along the wayside sends three phase AC power, in synchronization withtrain motion, to the windings. The power flows in a linear sequence to generate a magneticwave along the guideway. Only the section of the guideway under the train receives power asvehicle rides on the magnetic wave.GUIDEWAY CONFIGURATIONSThe one of the main advantages of maglev is the flexibility it offers in guidewaysconfigurations. Box Beam: In this vehicle straddles on a concrete box beam guideway. Interaction

between the vehicle magnets and laminated Aluminium ladder on each guidewaysidewall generates lift and guidance. Propulsion windings are also attached to theguideway sidewalls. Fig.[5].9 U - shaped guideway: Null flux (8-shaped) levitation coils located on the sidewalls

provide levitation and guidance. LSM propulsion coils are also located on sidewalls. T - shaped guideway: The vehicles wrap around this T shaped ferromagnetic

guideway.Levitation and guidance are based on EMS system. The electromagnets for levitaion arelocated underneath the guideway and that for guidance are mounted on the edge ofguideway. The guideway has LSM windings which interact with lift electromagnetsmounted on vehicle. Fig.[6]. Y - shaped guideway: Here the vehicle wraps around a Y-shaped ferromagnetic

guideway. The advantage is that a common set of vehicle magnets are used for levitation,guidance and proplulsion unlike in T-shaped which required two separate vehiclemagnets. The pole faces of vehicle electromagnets are attracted to the underside of theferromagnetic guideway. The guideway has LSM windings for propulsion.MAGLEV TRANSPORTATIONDue to the flexibility maglev offers many concepts of transportation which have been workedout, and the possibilities of many more are immense.We discuss here the concepts whose feasibilities have been established through extensivestudies. Maglev Trains: Maglev trains are capable of travelling at twice the speed of their

fastestcounterparts wheel-on-rail train TGV of France. The result is considerable trip timesavings and faster trips which makes its commercialisation feasible.Various commercial maglev train projects are in progress all over the world.1. Maglev track connecting cities of Washington and Baltimore10.2. Maglev track between Hamburg and Berlin and between downtown Pittsburgh & theairport in Germany1 .3. 34 km long Maglev track connecting Longyang Road Station on Metro Line II withPudong International Airport in China, designed for 433 kmph speed9.4. Maglev track between Osaka and Tokyo in Japan which would reduce the trip timefrom bullet train’s 2 hours 30 mins to 1 hour1. Autoshuttle6: It is a German dual-mode concept that utilizes Maglev carriers to

transport avariety of conventional vehicles like cars, trucks etc. Fig.[7].

10 Skytran7: Small podlike two-passenger cars would be suspended from a monorail-type

track that would support the levitating circuits. The cars would be available, on call, ateach station in the system. After the passengers board a car, it would glide up to the maintrack and merge with the traffic speeding by the station at 160 kmph. As a car approachesits destination, it would switch to an exit track, dropping down to the station to allow thepassengers to disembark. Fig.[8].MAGLEV LAUNCH SYSTEMStudies by NASA have shown that if their rockets could be accelerated up a sloping track tospeeds on the order of Mach 0.8 (950 kilometers per hour) before the rocket engines werefired up, it could substantially cut the cost of launching satellites. Such a system could reducethe required rocket fuel by 30 to 40 percent, thereby making it easier for a single-stage vehicleto boost a payload into orbit4. Refer fig.[9].NASA envisions a track a mile and a half long ( 2.4 km ) on which a winged craft would rideon a sled that would be magnetically levitated and propelled at an acceleration of 2 gs ( 19.6m/s2 ) until it reaches a speed of 400 milesph (643.6 kmph). The contestants of this NASAproject are PRT Advanced Maglev Systems, Foster-Miller and Lawrence Livermore NationalLab3.PRT Advanced Maglev Systems of Park Forest built a 50 feet (15.24 m) long working modelof spacecraft maglifter at Marshall Centre in Huntsville, Ala. The test vehicle weighing 30 lbreached speeds of 60 mph (96.54 kmph) in less than half a second3.Foster-Miller’s maglev launch system for NASA uses two sets of windings on the track. Oneset forms the stator that propels the vehicle and the other ,‘Null-Flux’, windings levitate andguide the vehicle. The experimental track built by it is 40 feet (12.2 m) long is in two parts:the first half contains the drive motor and the other comprise a magnetic brake. It was able togain 58 mph (93 kmph) in 20 feet (6.1 m) or in three-tenth of a second3.Lawrence Livermore National Laboratory in Livermore, California is building a mag-lifterusing permanent magnets arranged in Halbach array, thus avoiding use of superconductorswhich requires cooling at cryogenic temperatures. A 20 feet (6.1 m) long working model hasbeen built and a larger working model is under construction at Livermore3.11The goal of using magnetic levitation is to help to reach a target of reducing the cost oflaunching payload from the present $10,000 a pound to less than $1000 and perhapseventually to $200 a pound or so3.ADVANTAGES OF MAGLEV_ Unlike trains or cars there is no surface contact or friction to slow them down. More speed

= More passengers._ Faster trips :- High peak speed and high acceleration/braking enable average speed 3-4times the national highway speed limit of 65 mph (105 kmph)._ High reliability :- Less susceptible to congestion and wheather conditions than air andhighway._ Petroleum independence with respect to air and auto as a result of being electricallypowered._ Less polluting as a result of being electrically powered. Emissions can be controlled moreeffectively at the source of electric power generation than at many points of consumption,such as with air and automobile usage._ Higher capacity than air. At least 12,000 passengers with potential for even highercapacities at 3-4 minutes headways1._ High safety – both percieved and actual as based on the experiments._ Convinience and Comfort – due to high frequency of service, vibration free, smooth-assilktrain rides and quieter. At speeds below 155 mph (249.4 kmph) the noise produced byMaglev trains is less than that by conventional trains. At speeds above 155 mph, most ofthe noise produced by vehicle is of aerodynamic origin, wheather it is on rail or levitated1.12CONCLUSIONAny practical and commercial use of maglev has to be examined for technical & financialfeasibility.The technical feasibility has been stablished by status of Japanese MLU002 prototype systemcurrently being run in yamanshi test line5 & by German transrapid system at Emsland testfacility8. Both test systems have have supplemented Maglev as the promise of a faster,smoother, clean and safer ride.The other aspect of financial feasibility is subjective to a country. To judge its financialfeasibility its cost and revenue estimates have to be extensively studied in context of thegeography, demography and existing transportation systems. Studies in America were carriedout by National Maglev Initiative (NMI) evaluated Maglev potential and in short theirconclusion was that a 300 mph ( 483 kmph ) is entirely feasible1. Various commercial projectsin America, Germany, China and Japan should leave no room of doubt for its economicalviability. The need to upgrade this technology for a nation can be summed up in one sentencethat high mobility is linked with eonomic growth and productivity of nation.India has the most complex, widespread rail network which is now bogged down bycongestion. Maglev provides the flexibility to equip existing steel tracks with magneticlevitation (based on EDS) and propulsion system. This will help in operating both maglev andconventional trains on same track. The possible incorporation of both steel track and maglevguideway is hinted in figure. By this we can replace the conventional trains with maglevtrains in phased manner.The space launch systems based on maglev are also feasible as indicated by NASA. Varioustest models have proved its technical feasibility and cost studies by NASA clearly indicate

cheaper launching in future.Over the years India has developed strong infrastructure for space exploration and has its ownarray of launch vehicles and a reusable vehicle ‘Avataar’ on the cards. With NASA in persuitof low cost maglev launch its time that India too must venture into this field so that it cancompete, in the growing billion dollar market of satellite launch, in future.13REFERENCES1. National Maglev Initiative (NMI), formed by DOT, DOE, USACE and others, (U.S.),‘Final Report on the National Maglev Initiative’, www.bts.gov .2. Leo O’ Connor, Associate Editor,’US Developers Join Magnetic Rail Push’, MechanicalEngineering, ASME, NewYork, August 1993.3. Barbara Wolcott, ‘Induction for the Birds’, Mechanical Engineering, ASME, NewYork,Feb 2000.4. Dr. Richard F. Post., Inventor of Inductrack Passive Magnetic Levitation, ‘Maglev: ANew Approach’, Scientific American, Jan 2000.5. Railway Technical Research Institute, Japan, ‘Maglev’, www.rtri.or.jp .6. ‘Autoshuttle’, www.autoshuttle.de .7. ‘Skytran’, www.skytran.net .8. ‘Transrapid International’, www.transrapid.de .9. ‘Shanghai Builds Maglev Rail Line’, www.goldsea.com10. ‘Baltimore-Washington Project’, www.bwmaglev.com

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FaaDoOEngineers.com“DRIVING WITHOUT WHEELS, FLYING WITHOUT WINGS” 2

Abstract This paper “Driving without wheels, Flying without wings” deals with the present scenario of magnetic levitation (maglev) with Linear induction motor (LIM) .The magnetically levitated train has no wheels, but floats-- or surfs-- on an electromagnetic wave, enabling rides at 330 miles per hour. By employing no wheels, maglev eliminates the friction, and concomitant heat, associated with conventional wheel-on-rail train configurations. There are two basic types of non-contact Maglev systems Electro Dynamic Suspension (EDS), and Electro Magnetic Suspension (EMS). EDS is commonly known as "Repulsive Levitation," and EMS is commonly known as "Attractive Levitation." Each type of Maglev system requires propulsion as well as "levitation." The various projects above use different techniques for propulsion, but they are all variations of the Linear Induction Motor (LIM) or Linear Synchronous Motor (LSM).The conversion to a linear geometry has a far greater effect on induction motor performance than on that of synchronous motors. The cost of making the guideway is a high percentage of the total investment for a maglev system. The comparison looks even better for maglev when the terrain becomes difficult. Many of the tunnels, embankments, and cuttings necessary for roads and railroads are avoided because maglev guideways can be easily adapted to the topography. The Maglev system requires a slightly larger start-up capital construction cost, its operating cost-- because it deploys electricity in electromagnets in an extraordinarily efficient manner, rather than using as a fuel source coal, gas or oil-- can be one-half that of conventional rail. The crucial point is that maglev will set off a transportation and broader scientific explosion. Key words: Magnetic levitation , Levitation , Propulsion , Linear induction motor(LIM). 3

Introduction: Air flights are and will remain beyond the reach of a major section of society, particularly in India. Moreover there are problems of wastage of time in air traffic delays and growing safety concerns. Trends in increased mobility of large masses with changing lifestyle for more comfort are leading to congestion on roads with automobiles. Besides, increasing pollution levels from automobiles, depleting fuel resources, critical dependence on the fuel import and due to a limited range of mobility of buses and cars the need for fast and reliable transportation is increasing throughout the world. High-speed rail has been the solution for many countries. Trains are fast, comfortable, and energy-efficient and magnetic levitation may be an even better solution. Development of magnetic levitated transport systems is under progress in developed countries and it is just a matter of time they make inroads to India as well. Therefore, it will be interesting to know about the science and technology behind mass ground transport system known as "magnetic flight". A LITTLE HISTORY In 1922 a German engineer named Hermann Kemper recorded his first ideas for an electromagnetic levitation train. He received a patent in 1934 and one year later demonstrated the first functioning model. It wasn't until 1969, however, that a government-sponsored research project built the first full scale functioning Transrapid 01. The first passenger Maglev followed a few years later and carried people a few thousand feet at speeds up to 50 mph. The company, Munich's KraussMaffei, which built the first Transrapid, continued to build improved versions in a combined public-private research effort and completed Transrapid 02 in 1971, TR 03 in 1972 and TR 04 in 1973. The Transrapid 04 Transrapid 05 carried 50,000 visitors between parking and exhibition halls for six months. A test center, including a 19-mile figure "eight" test track, was erected between the years of 1979 and 1987 in North Germany. Going into service with the new test facility in 1979 was the vehicle Transrapid 06. This vehicle reached a speed of 221mph shortly after the completion of the first 13-mile section of track. With the completion of the track, the TR 06 eventually achieved a speed of 256 mph, traveling some 40,000miles before being retired in 1990. Through the continuous testing and refinements on the TR 06, it became possible to build the next generation vehicle Transrapid 07, built by the Thyssen Co. in Kassel. Since 1989, the Transrapid 07 has been the workhorse reaching the record speed of 280 mph and traveling some some 248,000 miles by the end of 1996.The most significant milestone was reached in 1991 when the Transrapid system received its certification certification of commercial worthiness. 4

Principle Of Operation: Imagine that two bar magnets are suspended one above the other with like poles (two north poles or two south poles) directly above and below each other. Any effort to bring these two magnets into contact with each other will have to overcome the force of repulsion that exists between two like magnetic poles. The strength of that force of repulsion depends, among other things, on the strength of the magnetic field between the two bar magnets. The stronger the magnet field, the stronger the force of repulsion. If one were to repeat this experiment using a very small, very light bar magnet as the upper member of the pair, one could imagine that the force of repulsion would be sufficient to hold the smaller magnet suspended—levitated—in air. This example illustrates the principle that the force of repulsion between the two magnets is able to keep the upper object suspended in air. In fact, the force of repulsion between two bar magnets would be too small to produce the effect described here. In actual experiments with magnetic levitation, the phenomenon is produced by magnetic fields obtained from electromagnets. For example, imagine that a metal ring is fitted loosely around a cylindrical metal core attached to an external source of electrical current. When current flows through the core, it sets up a magnetic field within the core. That magnetic field, in turn, sets up a current in the metal ring which produces its own magnetic field. According to Lenz's law, the two magnetic fields thus produced—one in the metal core and one in the metal ring—have opposing polarities. The effect one observes in such an experiment is that the metal ring rises upward along the metal core as the two parts of the system are repelled by each other. If the current is increased to a sufficient level, the ring can actually be caused to fly upward off the core. Alternatively, the current can be adjusted so that the ring can be held in suspension at any given height with relation to the core. MAGNETIC LEVIATION: Magnetic levitation transport, or maglev, is a form of transportation that suspends, guides and propels vehicles via electromagnetic force. This method can be faster and more comfortable than wheeled mass transit systems. Maglevs could potentially reach velocities comparable to turboprop and jet aircraft (500 to 580 km/h). Since much of a Maglev's propulsion system is in the track rather than the vehicle, Maglev trains are lighter and can ascend steeper slopes than conventional trains. They can be supported on lightweight elevated tracks. Maglevs have operated commercially since 1984. However, scientific and economic limitations have hindered the proliferation of the technology. 5

Magnetic levitation is the use of magnetic fields to levitate a (usually) metallic object. Manipulating magnetic fields and controlling their forces can levitate an object. In this process an object is suspended above another with no other support but magnetic fields. The electromagnetic force is used to counteract the effects of gravitation. . The forces acting on an object in any combination of gravitational, electrostatic, and magnetostatic fields will make the object's position unstable. The reason a permanent magnet suspended above another magnet is unstable is because the levitated magnet will easily overturn and the force will become attractive. If the levitated magnet is rotated, the gyroscopic forces can prevent the magnet from overturning. Several possibilities exist to make levitation viable. It is possible to levitate superconductors and other diamagnetic materials, which magnetize in the opposite sense to a magnetic field in which they are placed. A superconductor is perfectly diamagnetic which means it expels a magnetic field (Meissner-Ochsenfeld effect). Other diamagnetic materials are common place and can also be levitated in a magnetic field if it is strong enough. Diamagnetism is a very weak form of magnetism that is only exhibited in the presence of an external magnetic field. The induced magnetic moment is very small and in a direction opposite to that of the applied field. When placed between the poles of a strong electromagnet, diamagnetic materials are attracted towards regions where the magnetic field is weak. Diamagnetism can be used to levitate light pieces of pyrolytic graphite or bismuth above a moderately strong permanent magnet. As Superconductors are perfect diamagnets and when placed in an external magnetic field expel the field lines from their interiors (better than a diamagnet). The magnet is held at a fixed distance from the superconductor or vice versa. This is the principle in place behind EDS (electrodynamic suspension) maglev trains. The EDS system relies on superconducting magnets. A maglev is a train, which is suspended in air above the track, and propelled forward using magnetism. Because of the lack of physical contact between the track and vehicle, the only friction is that between the carriages and air. So maglev trains can travel at very high speeds (650 km/h) with reasonable energy consumption and noise levels. Due to the lack of physical contact between the track and the vehicle, the only friction exerted is 6

that between the vehicles and the air. If it were the case that air-resistance were only a minor form of friction, it would be appropriate to say "Consequently maglevs can potentially travel at very high speeds with reasonable energy consumption and noise levels. Systems have been proposed that operate at up to 650 km/h (404 mph), which is far faster than is practical with conventional rail transport". But this is not true. In an ordinary high speed train, most of the friction is air resistance. The power consumption per passenger-km of the Transrapid Maglev train at 200 km/h is only 24% less than the ICE at 200 km/h (22 W per seat-km, compared to 29 W per seat-km). The very high maximum speed potential of maglevs make them competitors to airline routes of 1,000 kilometers (600 miles) or less levitation Each type of Maglev system requires propulsion as well as "levitation." The various projects below use different techniques for propulsion. The first thing a maglev system must do is get off the ground, and then stay suspended off the ground. This is achieved by the electromagnetic levitation system. Another experimental technology, which was designed, proven mathematically, peer reviewed, and patented, but is yet to be built, is the magnetodynamic suspension (MDS), which uses the attractive magnetic force of a permanent magnet array near a steel track to lift the train and hold it in place. Other technologies such as repulsive permanent magnets and superconducting magnets have seen some research. Electromagnetic suspension: In current electromagnetic suspension (EMS) systems, the train levitates above a steel rail while electromagnets, attached to the train, are oriented toward the rail from below. The system is typically arranged on a series of C-shaped arms, with the upper portion of the arm attached to the vehicle, and the lower inside edge containing the magnets. The rail is situated between the upper and lower edges. Magnetic attraction varies with the cube of distance, so minor changes in distance between the magnets and the rail produce greatly varying forces. These changes in force are dynamically unstable - if there is a slight divergence from the optimum position, the tendency will be to exacerbate this, and complex systems of feedback control are required to maintain a train at a constant distance from the track, (approximately 15 millimeters (0.6 in)).[21][22] The major advantage to suspended maglev systems is that they work at all speeds, unlike electrodynamic systems (see below) which only work at a minimum speed of about 30 km/h. This 7

eliminates the need for a separate low-speed suspension system, and can simplify the track layout as a result. On the downside, the dynamic instability of the system demands high tolerances of the track, which can offset, or eliminate this advantage. Laithwaite, highly skeptical of the concept, was concerned that in order to make a track with the required tolerances, the gap between the magnets and rail would have to be increased to the point where the magnets would be unreasonably large.[20] In practice, this problem was addressed through increased performance of the feedback systems, which allow the system to run with close tolerances The principal two systems: EMS- attractive and EDS-repulsive, respectively. In the EMS-attractive system, the electromagnets which do the work of levitation 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. The gap between the bottom of the vehicle and the rail is only 3/8" and an electronic monitoring system, by controlling the amount of attractive force, must closely control the size of the gap. 8

Electrodynamic suspension EDS Maglev Propulsion via propulsion coils In electrodynamic suspension (EDS), 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 (as in JR-Maglev) or by an array of permanent magnets (as in Inductrack). The repulsive force in the track is created by an induced magnetic field in wires or other conducting strips in the track. A major advantage of the repulsive maglev systems is that they are naturally stable - minor narrowing in distance between the track and the magnets create strong forces to repel the magnets back to their original position, while a slight increase in distance greatly reduced the force and again returns the vehicle to the right separation. No feedback control is needed. Repulsive systems have a major downside as well. 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 or some other form of landing gear to support the train until it reaches a speed that can sustain levitation. Since a train may stop at any location, due to equipment problems for instance, the entire track must be able to support both low-speed and high-speed operation. Another downside is that the repulsive system naturally creates a field in the track in front and to the rear of the lift magnets, which act against the magnets and create a form of drag. This is generally only a concern at low speeds, at higher speeds the effect does not have time to build to its full potential and other forms of drag dominate. The drag force can be used to the electrodynamic system's advantage, however, as it creates a varying force in the rails that can be used as a reactionary system to drive the train, without the need for a separate reaction plate, as in most linear motor systems. Laithwaite led development of such "traverse-flux" systems at his Imperial College lab Alternately, propulsion coils on the guideway are used to exert a force on the magnets in the train and make the train move forward. The propulsion coils that exert a force on the train are effectively a linear motor: an alternating current flowing through the coils generates a continuously varying magnetic field that moves forward along the track. The frequency of the alternating current is synchronized to match the speed of the train. The offset between the field exerted by magnets on the train and the applied field creates a force moving the train forward. 9

In the EDS-repulsive system, the superconducting magnets (SCMs), which do the levitating of the vehicle, are at the bottom of the vehicle, but above the track. The track or roadway is either an aluminum guideway or a set of conductive coils. The magnetic field of the superconducting magnets aboard the maglev vehicle induces an eddy current in the guideway. The polarity of the eddy current is same as the polarity of the SCMs onboard the vehicle. Repulsion results, "pushing" the vehicle away and thus up from the track. The gap between vehicle and guideway in the EDS-system is considerably wider, at 1 to 7 inches, and is also regulated (by a null-flux system). Thus, the guideway is not below, but out to the sides. Now the repulsion goes perpendicularly outward from the vehicle to the coils in the guidewalls. The perpendicular repulsion still provides lift. they are all variations of the Linear Induction Motor (LIM) or Linear Synchronous Motor (LSM). Choice of linear electric motor A linear electric motor (LEM) is a mechanism which converts electrical energy directly into linear motion without employing any intervening rotary components. The development of one type of LEM, Linear synchronous motor (LSM), is illustrated in graphic form in Figure IV-1. A conventional rotary synchronous motor (above), such as that powering an electric clock, 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 10

which causes the change in polarity 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. It is not a new technology but merely design in a different form. Only the shape and the way it produces motion is changed. But there are advantages: no moving parts, silent operation, reduced maintenance, compact size, ease of control and installation. 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. Speed can be controlled by either simple or complex systems. Stopping, starting, reversing, are all easy. LEM's have long been regarded as the most promising means of propulsion for future high-speed ground transportation systems. The proposed system, while not strictly qualifying as high-speed, still derives so many advantages from the utilization of an LEM that no other propulsion means is being considered at this stage. Within the broad range of possible LEM designs, many alternatives are available. The selection of the preferred configuration can perhaps best be understood through a discussion of the choices considered and the reasons for the rejection of the others. 1. Synchronous vs. induction motors. Far more effort has been put into research and development of linear induction motors (LIM's) than LSM's. LIM's do indeed have two distinct advantages. First of all, they are simpler and less costly to construct. The stationary element of the motor consists of nothing more than a rail or plate of a conducting material, such as aluminum. Alternating current applied to the coils of the moving electromagnets induces a fluctuating magnetic field around this conductor which provides the propulsive force. By contrast, LSM's require the installation of alternating north and south magnetic poles on both moving and stationary elements. Secondly, LIM's are self-starting, with the speed of motion being infinitely variable from zero up to the design maximum. LSM's, on the other hand, exhibit no starting torque; rotary motors of this type are generally equipped with auxiliary squirrel-cage windings so that they can act as induction motors until they reach operating speed. LSM's possess other advantages, however, which are more than sufficient to outweigh these faults. They are far more efficient; models have been built with efficiencies of 97% or more, whereas the highest value yet attained for an LIM scarcely exceeds 70%. This is true despite the fact that rotary synchronous motors enjoy only a slight efficiency advantage over rotary induction motors; apparently the conversion to a linear geometry has a far greater effect on induction motor performance than on that of synchronous motors. Moreover, the efficiency of an LSM is relatively 11

unaffected by the speed of travel; LIM's, on the other hand, do not reach peak efficiencies until they attain velocities which are well beyond those being considered here. An LSM also operates at a constant speed, which depends solely on the frequency of the alternating current applied to its armature. This feature offers opportunities for absolute speed control; under normal operation, there is no way for any moving conveyance to alter its prescribed position relative to that of any other vehicle on the track. This fact imparts to any ground transportation system employing LSM's an enormously high traffic capacity, many times greater than the maximum attainable using LIM's. The proposed system demands such a capacity if it is to fulfill its goal of providing the opportunity for individual travel from any point on the system to any other, and at any time, day or night. Reciprocally, it is this potential for carrying huge volumes of traffic, made up of both public and private vehicles and of both passengers and cargo, that can justify the extra expenditure needed for the construction of an LSM-powered system. Linear induction motor (LIM) in magnetic levitation The High Speed Surface Transport (HSST) system is propelled by linear induction motor. The HSST primary coils are attached to the carriage body and the track configuration is simple, using the steel rails and aluminum reaction plates. The HSST levitation system uses ordinary electromagnets that exerts an attractive force and levitate the vehicle. The electro-magnets are attached to the car, but are positioned facing the under side of the guide way's steel rails. They provide an attractive force from below, levitating the car. This attractive force is controlled by a gap sensor that measures the distance between the rails and electromagnets. A control circuit continually regulates the current to the electro-magnet , ensuring that the gap remains at a fixed distance of about 8 mm, the current is decreased. This action is computer controlled at 4000 times per second to ensure the levitation. As shown in figure, 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. The use of an electro-magnetic attractive force to both levitate and guide the car is a significant feature of HSST the system We can visualize an HSST linear motor as an ordinary electric induction motor that has been split open and flattened. This of linear motor has recently been used in various fields the fig illustrates in the HSST, the primary side coils of motor are attached to the car body in the secondary side reaction plates are installed along the guide way .this component acts as induction motor and ensures both propulsion and breaking force without any contact between car and guide way. This 12

system a car mounted primary linear induction system. The ground side requires only a steel plate backed by an aluminum or copper plate, meaning that the rail source is simple. One of the HSST's unique technical features is modules that correspond to the bogies on connectional rolling stock. Figure shows each consist primarily of a member of electromagnets for levitation guidance, a linear motor for propulsion and braking, and a hydraulic break system. The two modules on the left and right sides of the car connected beams and this unit is called levitation bogie because the levitation bogies run the entire length of the car, the load car and load on guide way are spread out and the advantages of magnetic levitation can be fully exploited. Characteristics of LIM In most vehicular propulsion systems, provision must be made for increasing the power when the demand increases due to acceleration, a heavier load, increased drag, headwinds, or climbing a hill. In the case of an automobile, this is done through manipulation of both the accelerator and the transmission. But all of this is accomplished automatically when an LIM is used. Whenever more power is needed, the moving magnet begins to lag further behind the stationary one; this results in an immediate increase in thrust. No separate control is needed. Moreover, when an LIM-powered vehicle descends a steep hill or decelerates into a station, the moving motor advances to a position where it leads the stationary one. Under these conditions, the motor performance is shown in the left half of Figure. This automatically results in the production of electrical energy which is fed back into the system with a frequency and phase coherent with the line voltage. In other words, LIM's are automatically regenerative. 13

REQUIREMENTS OF AN URBAN MAGLEV A thorough requirements document should be prepared during the initial stage of the program. This document creates a common set of guidelines, which is intended to keep the design team focused during the design/development process. Included are requirements for the system and major subsystems to assure the performance, ride comfort and safety of the passengers. cost of propulsion coils could be prohibitive, a propeller or jet engine could be used. Stability Earnshaw's theorem shows that any combination of static magnets cannot be in a stable equilibrium.[29] However, the various levitation systems achieve stable levitation by violating the assumptions of Earnshaw's theorem. Earnshaw's theorem assumes that the magnets are static and unchanging in field strength and that the relative permeability is constant and greater than 1 everywhere. EMS systems rely on active electronic stabilization. Such systems constantly measure the bearing distance and adjust the electromagnet current accordingly. All EDS systems are moving systems (no EDS system can levitate the train unless it is in motion). Because Maglev vehicles essentially fly, stabilisation of pitch, roll and yaw is required by magnetic technology. In addition translations, surge (forward and backward motions), sway (sideways motion) or heave (up and down motions) can be problematic with some technologies. POWER AND ENERGY USAGE Power for maglev trains is used to accelerate the train, and may be produced when the train slowed ("regenerative braking"), it is also usually used to make the train fly, and to stabilise the flight of the train, for air conditioning, heating, lighting and other miscellaneous systems. Power is also needed to force the train through the air ("air drag"). 14

At low speeds the levitation power can be significant, but at high speeds, the total time spent levitating to travel each mile is greatly reduced, giving reduced energy use per mile, but the air drag energy increases with the speed-squared, and hence at high speed dominates. Benefits of Magnetic Levitated Transportation system: * Unlike conventional transportation systems in which a vehicle has to carry the total power needed for the most demanding sections, the power of the maglev motor is dependent on the local conditions such as flat or uphill grades. * 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. * Despite the speeds up to 500 km/hour, passengers can move about freely in the vehicles at all times. * Maglev vehicle carries no fuel to increase fire hazard * The materials used to construct maglev vehicles are non-combustible, poor transmitters of heat, and able to withstand fire penetration. * In the unlikely event that a fire and power loss occurred simultaneously, the vehicle is automatically slowed down so that it stops at a predefined emergency power station. * A collision between two maglev trains is nearly impossible because the linear induction motors prevent trains running in opposite directions or different speeds within the same power section. Current Projects: Germany and Japan have been the pioneering countries in MagLev research. Currently operational systems include Transrapid (Germany) and High Speed Surface Transport (Japan). There are several other projects under scrutiny such as the SwissMetro, Seraphim and Inductrack. All have to do with personal rapid transit. Other Applications: NASA plans to use magnetic levitation for launching of space vehicles into low earth orbit. Boeing 15

is pursuing research in MagLev to provide a Hypersonic Ground Test Facility for the Air Force. The mining industry will also benefit from MagLev. There are probably many more undiscovered applications Boones and Banes: BOONS: Maintenance: Because the train floats along there is no contact with the ground and therefore no need for any moving parts. As a result there are no components that would wear out. This means in theory trains and track would need no maintenance at all. Friction: Because maglev trains float, there is no friction. Note that there will still be air resistance Less noise: because there are no wheels running along there is no wheel noise. However noise due to air disturbance still occurs. Speed: As a result of the three previous listed it is more viable for maglev trains to travel extremely fast, i.e. 500km/h or 300mph BANES: 1. Maglev guide paths are bound to be more costly than conventional steel railways.

2. The other main disadvantage is lack with existing infrastructure. For example if a high speed line between two cities it built, then high speed trains can serve both cities but more importantly they can serve other nearby cities by running on normal railways that branch off the high speed line. The high speed trains could go for a fast run on the high speed line, and then come off it for the rest of the journey. Maglev trains wouldn't be able to do that; they would be limited to where maglev lines run. This would mean it would be very difficult to make construction of maglev lines commercially viable unless there were two very large destinations being connected. The fact that a maglev train will not be able to continue beyond its track may seriously hinder its usefulness.

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COMPARISION: Compared to conventional trains Major comparative differences between the two technologies lie in backward-compatibility, rolling resistance, weight, noise, design constraints, and control systems. Backwards Compatibility Maglev trains currently in operation are not compatible with conventional track, and therefore require all new infrastructure for their entire route. By contrast conventional high speed trains such as the TGV are able to run at reduced speeds on existing rail infrastructure, thus reducing expenditure where new infrastructure would be particularly expensive (such as the final approaches to city terminals), or on extensions where traffic does not justify new infrastructure. Efficiency Due to the lack of physical contact between the track and the vehicle, maglev trains experience no rolling resistance, leaving only air resistance and electromagnetic drag, potentially improving power efficiency.[32] Weight The weight of the large electromagnets in many EMS and EDS designs is a major design issue. A very strong magnetic field is required to levitate a massive train. For this reason one research path is using superconductors to improve the efficiency of the electromagnets, and the energy cost of maintaining the field. Noise. Because the major source of noise of a maglev train comes from displaced air, maglev trains produce less noise than a conventional train at equivalent speeds. However, the psychoacoustic profile of the maglev may reduce this benefit: A study concluded that maglev noise should be rated like road traffic while conventional trains have a 5-10 dB "bonus" as they are found less annoying at the same loudness level.[33][34] Design Comparisons Braking and overhead wire wear have caused problems for the Fastech 360 railed Shinkansen. Maglev would eliminate these issues. Magnet reliability at higher temperatures is a countervailing comparative disadvantage (see suspension types), but new alloys and manufacturing techniques have resulted in magnets that maintain their levitational force at higher temperatures. As with many technologies, advances in linear motor design have addressed the limitations noted in early maglev systems. As linear motors must fit within or straddle their track over the full length of the train, track design for some EDS and EMS maglev systems is challenging for anything other than point-to-point services. Curves must be gentle, while switches are very long and need care to avoid breaks in current. An SPM maglev system, in which the vehicle permanently levitated over 17

the tracks, can instantaneously switch tracks using electronic controls, with no moving parts in the track. A prototype SPM maglev train has also navigated curves with radius equal to the length of the train itself, which indciates that a full-scale train should be able to navigate curves with the same or narrower radius as a conventional train. Control Systems EMS Maglev needs very fast-responding control systems to maintain a stable height above the track; this needs careful design in the event of a failure in order to avoid crashing into the track during a power fluctuation. Other maglev systems do not necessarily have this problem. For example, SPM maglev systems have a stable levitation gap of several centimeters. Compared to aircraft For many systems, it is possible to define a lift-to-drag ratio. For maglev systems these ratios can exceed that of aircraft (for example Inductrack can approach 200:1 at high speed, far higher than any aircraft). This can make maglev more efficient per kilometre. However, at high cruising speeds, aerodynamic drag is much larger than lift-induced drag. Jet transport aircraft take advantage of low air density at high altitudes to significantly reduce drag during cruise, hence despite their lift-to-drag ratio disadvantage, they can travel more efficiently at high speeds than maglev trains that operate at sea level (this has been proposed to be fixed by the vactrain concept). Aircraft are also more flexible and can service more destinations with provision of suitable airport facilities. Unlike airplanes, maglev trains are powered by electricity and thus need not carry fuel. Aircraft fuel is a significant danger during takeoff and landing accidents. Also, electric trains emit little carbon dioxide emissions, especially when powered by nuclear or renewable sources. 18

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: 1. Non-contact and non-wearing propulsion, independent of friction, no mechanical components like wheel, axle. Maintenance costs decrease. Low noise emission and vibrations at all speeds(again due to non-contact nature). Low specific energy consumption. Faster turnaround times, which means fewer vehicles. All in all, low operating costs. Speeds of up to 500kmph.. Low pollutant emissions. Hence environmentally friendly. 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.