Chapter-1

INTRODUCTION

Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended above another object with no support other than magnetic field. The electromagnetic force is used to counteract the effects of the gravitational force.

Maglev (derived from magnetic levitation), is a system of transportation that uses magnetic levitation to suspend, guide and propel vehicles from magnets rather than using mechanical methods, such as wheels, axles and bearings. Maglev transport is a means of flying a vehicle or object along a guide way by using magnets to create both lift and thrust, only a few inches above the guide way surface. High-speed maglev vehicles are lifted off their guide way and thus are claimed to move more smoothly and quietly and require less maintenance than wheeled mass transit systems – regardless of speed. It is claimed that non-reliance on friction also means that acceleration and deceleration can far surpass that of existing forms of transport. The power needed for levitation is not a particularly large percentage of the overall energy consumption; most of the power used is needed to overcome air resistance (drag), as with any other high-speed form of transport.

While several maglev systems are monorail designs, not all maglevs use monorails, and not all monorail trains use linear motors or magnetic levitation. Some railway transport systems incorporate linear motors but only use electromagnetism for propulsion, without actually levitating the vehicle. Such trains –which might also be monorail trains– are wheeled vehicles and not maglev trains.

 Air travel is also becoming more and more congested these days. Despite frequent delays, airplanes still provide the fastest way to travel hundreds or thousands of miles. Passenger air travel revolutionized the transportation industry in the last century, letting people traverse great distances in a matter of hours instead of days or weeks. The only alternatives to airplanes -- feet, cars, buses, boats and conventional trains -- are just too slow for today's fast-paced society. However, there is a new form of transportation that could revolutionize transportation of the 21st century the way airplanes did in the 20th century.

A few countries are using powerful electromagnets to develop high-speed trains, called maglev trains. Maglev is short for magnetic levitation, which means that these trains will float over a guideway using the basic principles of magnets to replace the old steel wheel and track trains. 

We know that opposite poles attract and like poles repel each other. This is the basic principle behind electromagnetic propulsion. Electromagnets are similar to other magnets in that they attract metal objects, but the magnetic pull is temporary. A small electromagnet can be easily created by connecting the ends of a copper wire to the positive and negative ends of a  battery. This creates a small magnetic field. If we disconnect either end of the wire from the battery,

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the magnetic field is taken away. The magnetic field created in this wire-and-battery experiment is the simple idea behind a maglev 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 train

The big difference between a maglev train and a conventional train is that maglev trains do not have 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 magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train.

Above is an image of the guideway for the Yamanashi maglev test line in Japan.

The highest recorded speed of a maglev train is 581 km/h (361 mph), achieved in Japan by the CJR's MLX01 superconducting maglev in 2003, 6 km/h (3.7 mph) faster than the conventional wheel-rail speed record set by the TGV.

Differences in construction costs can affect chances for profitability. Maglev advocates claim that with conventional railway trains, at very high speeds, the wear and tear from friction along with the concentrated pounding from wheels on rails accelerate equipment deterioration and prevent mechanically-based train systems from achieving a maglev-based train system's high level of performance and low levels of maintenance; Indeed, it was concerns about maintenance and safety that convinced Chinese authorities to announce a slowing down of all new conventional high-speed trains to 300 km/h (190 mph). There is a good reason why the rest of the world's fast trains limit their operations to similar top speeds and why the Central Japan Railway (CJR) is planning to build its newest Shinkansen (Chuo) line using maglev technology.

Chapter-2

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HISTORICAL BACKGROUND

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 Krauss Maffei, 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 248,000 miles by the end of 1996.The most significant milestone was reached in 1991 when the Transrapid system received its certification of commercial worthiness.

Chapter-3

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MAGNETICALLY LEVIATED TRAINS

The principal of a Magnet train is that floats on a magnetic field and is propelled by a linear induction motor. They follow guidance tracks with magnets. These trains are often referred to as Magnetically Levitated a train which is abbreviated to Maglev. Although maglev don't use steel wheel on steel rail usually associated with trains, the dictionary definition of a train is a long line of vehicles traveling in the same direction - it is a train.

A super high-speed transport system with a non-adhesive drive system that is independent of wheel-and-rail frictional forces has been a long-standing dream of railway engineers. Maglev, a combination of superconducting magnets and linear motor technology, realizes super high-speed running, safety, reliability, low environmental impact & minimum maintenance.

3.1 PRINCIPLE

The principle is that two similar poles (e.g., two North’s) repel, and two different poles attract, with forces that are stronger when the poles are closer. 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.

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3.2 WORKING

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.Super-cooled superconducting magnets are placed on the train cars while electromagnetic coils are placed along the track. Superconductors are used because they can conduct electricity even after the power supply has been shut off (unlike the EMS system). When the trains get close to the coils a current is induced which allows the train to levitate about 10 cm and centre itself in the middle of the guideway. To get the train moving a second set of coils are placed along the guidance coils and after the train reaches approximately 100km/h the propulsion coils are activated. The electric current that is constantly changing allows for a change in polarity of the electromagnets which in turn pushes and pulls the superconducting magnets of the passing train to allocate movement.

3.3 MAGLEV METHODS

The different methods which are used for magnetic levitation are as follows:

1. Repulsion between like poles of permanent magnets or electromagnets.

2. Repulsion between a magnet and a metallic conductor induced by relative motion.

3. Repulsion between a metallic conductor and an AC electromagnet.

4. Repulsion between a magnetic field and a diamagnetic substance.

5. Repulsion between a magnet and a superconductor.

6. Attraction between unlike poles of permanent magnets or electromagnets.

7. Attraction between the open core of an electromagnetic solenoid and a piece of iron or a magnet.

8. Attraction between a permanent magnet or electromagnet and a piece of iron.

9. Attraction between an electromagnet and a piece of iron or a magnet, with sensors and active control of the current to the electromagnet used to maintain some distance between them.

10. Repulsion between an electromagnet and a magnet, with sensors and active control of the current to the electromagnet used to maintain some distance between them.

Chapter-4

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MAGLEV VEHICLE CONSTRUCTION

Basically the construction depends on 3 different forces:

1. Propulsion force2. Levitating force3. Lateral guiding force

4.1 PROPULSION FORCE

This is a horizontal force which causes the movement of train. It requires 3 parameters.

Large electric power supply

Metal coil lining, a guide way or track.

Large magnet attached under the vehicle.

4.1.1 PRINCIPLE OF LINEAR MOTOR

The motor of a maglev system is the interaction between the electromagnets/superconducting magnets (SCMs) and the guideway; the package of the two, and their interaction is what constitutes the motor. Otherwise, there is no standing motor aboard, as in the case of train locomotive or automobile engine.

In a normal conventional motor, there are two principal parts: the stator, which is stationary; and the rotor, which can rotate as a result of action from the stator. But whatever the motor, in a maglev system, it is linearized, meaning that it is opened up, unwound, and stretched out, for as long as the track extends. Usually, the straightened stators, whether they be long or short, are embedded in the track, and the rotors are embedded in the electromagnetic system

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onboard the vehicle; but on occasion, in some systems, the roles can be reversed. This becomes important in the propulsion system.

Maglev vehicles are propelled primarily by one of the following three options:

1. A linear synchronous motor (LSM) in which coils in the guideway are excited by a three phase winding to produce a traveling wave at the speed desired; Trans Rapid in Germany employs such a system.

2. A Linear Induction Motor (LIM) in which an electromagnet underneath the vehicle induces current in an aluminum sheet on the guide way.

3. A reluctance motor is employed in which active coils on the vehicle are pulsed at the proper time to realize thrust.

4.1.2 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.

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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 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 Newton’s, 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.

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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.

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 aluminium. 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 affected 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 fulfil 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.

4.1.3 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 aluminium reaction plates. The HSST levitation system uses

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ordinary electromagnets that exerts an attractive force and levitate the vehicle. The electro-magnets are attached to the car, but are positioned facing the underside 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 whenever a levitational force is exerted, a lateral guidance force occurs as well. If the electromagnet starts to shift laterally from the centre 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 system a car mounted primary linear induction system. The ground side requires only a steel plate backed by an aluminium 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.

4.1.4 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.

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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.

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4.2 LEVITATING FORCE

Levitating force is produced due to the eddy current in the conducting ladder by the electromagnetic interaction. At low speed the force due to induced poles cancel each other. At high speed a repulsive force is taken place as the magnet is shifted over a particular pole.

Obtained Magnetic Levitation : It is proved that magnetic levitation cannot be obtained just by using static ferromagnetism, as the object would tend to gain instability. In order to create proper magnetic levitation condition, diamagnetic materials or superconductors have to be used. But in all these cases a little help from pseudo-levitation needs to be taken. Pseudo-levitation is a system that provides stability to the levitated object using a magnetic mechanism. For light objects, magnets made of diamagnetic materials are sufficient. The atoms of a diamagnetic substance such as silver and bismuth, doesn't have a specific dipole moment. When these objects are brought under the influence of a magnetic field, a dipole moment is induced in the direction opposite to that of the field applied. Because of this a repulsive force is generated that creates the desired levitation. Another way of obtaining magnetic levitation is by using electromagnetism. Electrodynamic fields are created when electricity is passed through a conductor. The moving charges that are created as a result of the magnetism, provides a vertical push that is equal to the gravitational pull, which in turn help to produce a stable levitation condition. Heavier objects are generally levitated by this method. Apart from these main methods, eddy currents or electrodynamic suspension, oscillating magnetic fields and permanent magnet suspension are also used.

How The Vehicle Levitates: 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". Now imagine a long line of magnets alternatively placed along a track. A line of alternatively placed magnets on the bottom of the train. If these magnets are properly controlled the trains will lift of the ground by the magnetic repulsion or magnetic attraction. On the basis of this principle, Magnetic Levitation is broken into three main types of suspension or levitation.

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There are 3 types of levitating systems :-

1. Electrodynamic suspension system

2. Electromagnetic suspension system

3. Inductrack system

4.2.1 EDS SYSTEM

In EDS both the rail and the train exert a magnetic field, and the train is levitated by the repulsive force between these magnetic fields. 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.

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. To understand what’s really going on here, lets start from the inside out. The first major difference between EDS and EMS is the type of track. Whereas with EMS the bottom of the train hooks around the edges of the track, an EDS train literally floats on air.

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EDS suspension has several positive and negative aspects to it. To begin, initial costs are high and most countries do not have the money or feel the need to spend it on this kind of transportation. Once up and running however, an EDS Maglev runs only on electricity so there is no need for other fuels. This reduction in fuel will prove to be very important to the sustainability of Maglev. One huge disadvantage of the EDS system is the great cost and inconvenience of having to keep the super cooled superconductive magnets at 5K. Another drawback is that in the event of a power failure, a Maglev train using EDS would slam onto the track at great speeds. This is a second reason for the wheels that are primarily used to get the train moving quickly enough for levitation. The wheels would need to have a shock system designed to compensate for the weight of the car and its passengers as the train falls to the track. In Japan, where EDS Maglev is in its testing stage, trains average about 300 km/hr and have been clocked at 552 km/hr, which is a world record for rail speed. Compared to Amtrak trains in the United States, which travel at an average of 130 km/hr, Maglev can get people where they need in about half of the time. The EMS and EDS suspension systems are the two main systems in use, but there is a possibility for a third to soon join the pack.

4.2.2 EMS SYSTEM

Maglev concepts using electro -magnetic suspension employ attractive forces. Magnetic fields inside and outside the vehicle are insignificant; proven, commercially available technology that can attain very high speeds (500 km/h); no wheels or secondary propulsion system needed.

The separation between the vehicle and the guideway must be constantly monitored and corrected by computer systems to avoid collision due to the unstable nature of electromagnetic attraction. 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

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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.

The small distance of about 10mm needs to be constantly monitored in order to avoid contact between the trains rails and the guiderail. This distance is also monitored by computers, which will automatically adjust the strength of the magnetic force to bring this distance back to around 10mm, if needed. This small elevation distance and the constant need for monitoring the Electromagnetic Suspension System is one of its major downfalls.

4.2.3 INDUCTRACK SYSTEM

The Inductrack guide way would contain two rows of tightly packed levitation coils, which would act as the rails . Each of these “rails” would be lined by two Halbach arrays carried underneath the maglev vehicle: one positioned directly above the “rail”and one along the inner side of the “rail”. The Halbach arrays above the coils would provide levitation while the Halbach arrays on the sides would provide lateral guidance that keeps the train in a fixed position on the track.

A major benefit of this track is that even if a power failure occurs, the train can continue to levitate because of the use of permanent magnets. As a result, the train is able to slow to a stop during instances of power failure. In addition, the train is able to levitate without any power source involved. The only power needed for this system is for the linear synchronous motor and the only power loss that occurs in this system is from aerodynamic drag and electrical resistance in the levitation circuits.

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Although this type of track is looking to be used, it has only been tested once on a 20-meter track. NASA is working together with the Inductrack team to build a larger test model of 100 meters in length. This testing could eventually lead to a workable Maglev system for the future. The Inductrack system could also be used for the launching of NASAs space shuttles. The following picture displays side by side all three types of levitation systems. 

4.3 LATERAL GUIDING FORCE

The Lateral guidance systems control the trains ability to actually stay on the track. It stabilized the movement of the train from moving left and right of the train track by using the system of electromagnets found in the undercarriage of the MagLev train. The placement of the electromagnets in conjunction with a computer control system ensures that the train does not deviate more than 10mm from the actual train tracks. 

The lateral guidance system used in the Japanese electrodynamic suspension system is able to use one set of four superconducting magnets to control lateral guidance from the magnetic propulsion of the null flux coils located on the guideways of the track. Coils are used frequently in the design of MagLev trains because the magnetic fields created are perpendicular to the electric current, thus making the magnetic fields stronger. The Japanese Lateral Guidance system also uses a semi-active suspension system. This system dampens the effect of the side to side vibrations of the train car and allows for more comfortable train rides. This stable lateral motion caused from the magnetic propulsion is a joint operation from the acceleration sensor, control devive, to the actual air spring that dampens the lateral motion of the train car.

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Guidance or steering refers to the sideward forces that are required to make the vehicle follow the guideway. The necessary forces are supplied in an exactly analogous fashion to the suspension forces, either attractive or repulsive. The same magnets on board the vehicle, which supply lift, can be used concurrently for guidance or separate guidance magnets can be used.

It requires the following arrangements:

• Guideway levitating coil

• Moving magnet

Chapter-5

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EXISTING MAGLEV SYSTEMS

5.1 GERMANY’S MAGLEV

Emsland, Germany Transrapid, a German maglev company, has a test track in Emsland with a total length of 31.5 km (19.6 mi). The single track line runs between Dörpen and Lathen with turning loops at each end. The trains regularly run at up to 420 km/h (260 mph). The construction of the test facility began in 1980 and finished in 1984.

Germany’s Maglev:The “Transrapid”

5.2 SHANGHAI’S MAGLEV

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Transrapid, in Germany, constructed the first operational high-speed conventional maglev railway in the world, the Shanghai Maglev Train from downtown Shanghai (Shanghai Metro) to the Pudong International Airport. It was inaugurated in 2002. The highest speed achieved on the Shanghai track has been 501 km/h (311 mph), over a track length of 30 km. Construction of an extension to Hangzhou is planned to begin in 2010.

Shanghai’s Maglev

5.3 JAPAN’S MAGLEV

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Japan has a demonstration line in Yamanashi developed by the Central Japan Railway Company (JR Central) and Kawasaki Heavy Industries are currently the fastest trains in the world, achieving a record speed of 581 km/h on December 2, 2003.JR Central runs the MLX01 maglev bullet train, still in its testing phase. The Japanese program began in 1962, with testing starting in 1997 on the 18.4-kilometer test line between Tsuru and Otsuki, 30 miles north of Miyazaki, in Yamanashi Prefecture on Kyushu. In 1999, the Japanese maglev train has reached speeds of 552 kph (325mph). In 2003 it clocked the world’s fastest trial run of 581 kilometers (361 miles) an hour. French high speed trains have reached 515kph. 

Japan's MLX01 Maglev Train

Chapter-6

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APPLICATIONS

Maglev train is a famous application of the maglev technology . Almost all the prominent countries have these trains as a major mode of transport in their system. Apart from this, maglev toys are also quite famous and are available in all the markets. Some of the famous maglev toys are maglev toy train, maglev toy cars, maglev clocks etc. Future might see maglev technology put to use in a variety of applications. Maglev cars are supposed to be under development. These cars wonâ„¢t require a track but would fly in air. NASA is working on a maglev catapult that is predicted to reduce the costs and launching problems of a spacecraft. Also, Maglev elevators are already made and soon be put to use in Japan and China.

6.1 MAGNETIC LEVITATION TRAINS

In today's fast-paced and technological society, efficiency is critical. One essential factor in our lives is transportation- traveling between our home and workplace-and moving goods to marketplaces- to name a few examples. Consequently, other than airplanes, the conventional methods of transport such as cars, buses, and ships, are incomparable to more advanced transportation methods, such as maglev trains. Maglev, which stands for magnetic levitation, is a system of transportation that levitates, guides, and propels trains, with magnetism. Electromagnets along the guide-way beams and magnets underneath the train allow for repulsions and attractions, which move the train along the track. Steel wheels and tracks are removed to create a frictionless ride, allowing for speeds above 500 km/h. Specifically, only magnetic fields are relevant to the maglev train. Metal coils lining a guide-way become electromagnets when an electrical current runs through them, to begin the movement of the maglev train. The magnetic field created by this electromagnet is used to levitate the train 1-10 cm above the track by repelling the large magnets attached to the underside of the train. The beams on either side of the track also contain metal coils used for propulsion. Once the train begins to levitate, an electric current is supplied to these propulsion coils, which creates a combination of magnetic fields that push and pull the train along the track. The electric current in these coils constantly alternate to change to polarity of the electromagnets. This change in polarity causes the magnetic field in front of the train to pull it forward, while the magnetic field behind it adds more forward thrust. It is the lack of friction and the train's aerodynamic design that allow for speeds over 500 km/h. All can benefit from the maglev train, and especially those who travel regularly. The benefit extends to individuals, allowing people to reach their destinations quickly and efficiently. In addition, the benefit also extends to the country, by allowing for the employment of engineers in many countries around the world to perfect new construction methods, being a source of revenue for the country, and by reducing energy consumption, air pollution, and noise pollution. Unfortunately, maglev trains have also had a negative impact on society. The track of a Maglev train is small compared to those of a conventional train and is elevated above the

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ground so the track itself will not have a large effect on the topography of a region. Since a Maglev train levitates above the track, it will experience no mechanical wear and thus will require very little maintenance. Ultimately, maglev trains have the potential to change the lives of people around the world, with unprecedented ground transportation speed.

6.2 MAGNETIC LEVITATION WIND TURBINE

Magnetic levitation is a method by which an object is suspended above another object with no support other than magnetic fields. The electromagnetic force is used to counteract the effects of the gravitational force. Magnetic levitation is used to reduce the energy loss due to friction. This energy wasted in friction can be saved by maglev method. Windmill is having maximum overall efficiency of 30%. Energy efficient windmill can operate in the maximum efficiency of 45%. The remaining energy is mainly lost in friction. If the same windmill is operating at 50% of its maximum speed the efficiency becomes very low and the frictional loss gets increased compared to power generated. The drawback of windmill is that it cannot be operated at its full capacity all the time. Wind energy has been identified as one of the green energies, the future world depends. Many countries started investing more money in wind generation. So losses in windmill shall be reduced to tap the maximum power from wind. To reduce the loss, maglev method can be implemented. Moreover due to friction there will be wear and tear in machines. Due to the wear and tear the performance of the machine will deteriorate. Hence windmill using magnetic levitation has more life than ordinary windmill. Normal windmill can start its generation from wind speed of 3 m/s. But windmill

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using magnetic levitation can start generation from wind speed of 1.5m/s. Operation of windmill at lower speeds, increases the amount of energy harvested from the windmill. Magnetic Levitation Wind Turbine are also called the Regenedyne. This technique is efficient, frictionless, a single unit capable of producing the power of 500 standard commercial turbines, maglev technology was said to have it all.

Chapter-7

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ADVANTAGES

7.1 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.

7.2 MAINTENANCE

There is very little maintenance because there is no contact between the track and the vehicle. There is no rolling friction leaving only air resistance.

7.3COMFORT

The ride is smooth while not accelerating. But passengers traveling in a 250 mph Maglev train will feel much stronger gravitational forces in rounding an interstate curve than will passengers in a car moving at 65 mph

7.4 ECONOMIC EFFICIENCY

The initial investment is similar to other high speed rail roads. Operating expenses are half of that of other railroads. A train is composed of sections that each contain 100 seats, and a train can have between 2 and 10 sections.

7.5 SPEEDThe train can travel at about 300 mph. For trips of distances up to 500 miles its total travel time is equal to a planes. It can accelerate to 200 mph in 3 miles, so it is ideal for short jumps.

7.6 ENVIRONMENTNo burning of fossil fuel, so no pollution, and the electricity needed will be nuclear or solar. It uses less energy than existing transportation systems. For every seat on a 300 km trip with 3 stops, the gasoline used per 100 miles varies with the speed. At 200 km/h it is 1 liter, at 300 km/h it is 1.5 liters and at 400 km/h it is 2 liters. This is 1/3 the energy used by cars and 1/5 the energy used by jets per mile. The tracks have less impact on the environment because the elevated models (50ft in the air) allows all animals to pass, low models (5-10 ft) allow smallanimals to pass, they use less land than conventional trains, and they can follow the landscape better than regular trains since it can climb 10% gradients (while other trains can only climb 4 gradients) and can handle tighter turns.

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7.7 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. Initial tests suggest that MAGLEV vehicles may produce a high level of noise when they operate at top speed. Tests have shown that sound levels of 100 decibels at a distance of 80 ft (24 m) from the guide way may be possible. Such levels of sound are, however, unacceptably high for any inhabited area.

Chapter-8

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CONCLUSION

Magnetic levitation is a phenomena that is likely to have considerable potential in the future. Particularly through the use of superconductive levitation. A new idea for magnetic levitation is in the use of storage of energy. Very basically it uses a rotating ring (flywheel) that stores (kinetic) moving energy which can be 'extracted'. It is use of magnetic fields to levitate a metallic object .By manipulating magnetic fields and controlling their forces an object can be levitated. Because of the growing need for quicker and more efficient methods for moving people and goods, researchers have turned to a new technique, one using electromagnetic 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 vehicles are suspended and guided by magnetic forces. Instead of engines, maglev vehicles use electromagnetism to levitate (raise) and propel the vehicle. There is much work to be done in the Maglev industry, but the basic physics argue that these new systems will penetrate the transportation system because of weight and efficiency over the ever present wheel. One other variation that might surface in the near future is a hybrid system, one in which magnets are employed to simply lighten the effective load placed on the wheels. Railways using Maglev technology are on the horizon. They have proven to be faster than traditional railway systems that use metal wheels and rails and are slowed by friction. The low maintenance of the Maglev is an advantage that should not be taken lightly. Energy saved by not using motors running on fossil fuels allows more energy efficiency and environmental friendliness. Maglev will have a positive impact on sustainability. Using superconducting magnets instead of fossil fuels, it will not emit greenhouse gases into the atmosphere. Energy created by magnetic fields can be easily replenished. Maglev will contribute more to our society and our planet than it takes away. Considering everything Maglev has to offer, the transportation of our future and our childrens future is on very capable tracks.

Railways using MagLev technology are on the horizon.They have proven to be faster than traditional railway systems that use metal wheels and rails and are slowed by friction. The low maintenance of the MagLev is an advantage that should not be taken lightly. When you don’t have to deal with the wear and tear of contact friction you gain greater longevity of the vehicle. Energy saved by not using motors running on fossil fuels allow more energy efficiency and environmental friendliness.

Maglev will have a positive impact on sustainability. Using superconducting magnets instead of fossil fuels, it will not emit greenhouse gases into the atmosphere. Energy created by magnetic fields can be easily replenished. The track of a Maglev train is small compared to those of a conventional train and are elevated above the ground so the track itself will not have a large effect on the topography of a region. Since a Maglev train levitates above the track, it will experience no mechanical wear and thus will require very little maintenance.Overall, the sustainability of Maglev is very positive. Although the relative costs of

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constructing Maglev trains are still expensive, there are many other positive factors that overshadow this. Maglev will contribute more to our society and our planet than it takes away. Considering everything Maglev has to offer, the transportation of our future and our children’s future is on very capable tracks.

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REFERENCES

1. Sawada, Kazuo, "Magnetic Levitation (Maglev) Technologies 1. Supderconducting Maglev Developed by RTRI and JR Central", Japan Railway & Transport Review, No. 25,pp 58-61

2. He, J. L., Coffey, H. T., Rote, D.M. "Analysis of the Combined MagLev Levitation, Propulsion, and Guidance System", IEEE Transactions on Magnetics, Vol 31, No.# 2, pp 981-987, March 1995

3. Zhao, C. F., Zhai, W. M., "MagLev Vehicle/Guideway Vertical Random Response and Ride Quality", Vehicle System Dynamics, Vol 38, No # 3., pp 185-210, 2002

4. Cassat, A., Jufer, M. "MAGLEV Projects Technology Aspects and Choices", Transactions on Applied Superconductivity, Vol 12, No. # 1, pp 915-925, March 2002

5. “Final Report on the National Maglev Initiative”, National Maglev Initiative (NMI), formed by DOT, DOE, USACE and others, (U.S.)

6. “US Developers Join Magnetic Rail Push”, Leo O’ Connor, Associate Editor, Mechanical Engineering, ASME, New York, August 1993

7. “Induction for the Birds”, Barbara Wolcott, Mechanical Engineering, ASME, NewYork, Feb 2000

8. “Maglev: A New Approach”, Dr. Richard F. Post., Scientific American, Jan 2000

9. “Electromagnetic suspension dynamics & control”, Sinha, P. K., Peter Peregrinus Ltd, London, United Kingdom, 1987.

10. “Maglev: The New Mode of Transport for the 21st Century”, Powell, J., Danby G, 21st Century Science & Technology Summer Issue.http://www.21stcenturysciencetech.com/articles/Summer03/maglev2.

11. “Technical Assessment of Maglev System Concepts”, Lever, J. H., Final Report by the Government Maglev System Assessment Team.

12. http://en.wikipedia.org/wiki/Maglev

13. http://science.howstuffworks.com

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