maglev report part 2 ashish

7/31/2019 Maglev Report Part 2 Ashish

http://slidepdf.com/reader/full/maglev-report-part-2-ashish 1/23

Magnetic Levitated Trains (MAGLEV)

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Elec. & Comm. Department, MAIET

CHAPTER-1

INTRODUCTION OF MAGNETIC LEVITATION

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.

A substance which is diamagnetic repels a magnetic field. All materials have

diamagnetic properties, but the effect is very weak, and usually overcome by the

object's paramagnetic or ferromagnetic properties, which act in the opposite manner.

Any material in which the diamagnetic component is strongest will be repelled by a

magnet, though this force is not usually very large. Diamagnetic levitation can be

used to levitate very light pieces of pyrolytic graphite or bismuth above a moderately

strong permanent magnet. As water is predominantly diamagnetic, this technique has

been used to levitate water droplets.




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The minimum criterion for diamagnetic levitation is,

Where:

χ is the magnetic susceptibility

ρ is the density of the material

g is the local gravitational acceleration (-9.8 m/s2 on Earth)

μ0 is the permeability of free space

B is the magnetic field

is the rate of change of the magnetic field along the vertical axis.

Assuming ideal conditions along the z-direction of solenoid magnet:

Water levitates at

Graphite at




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MAGLEV METHODS

Repulsion between like poles of permanent magnets or electromagnets.

Repulsion between a magnet and a metallic conductor induced by relativemotion.

Repulsion between a metallic conductor and an AC electromagnet.

Repulsion between a magnetic field and a diamagnetic substance.

Repulsion between a magnet and a superconductor.

Attraction between unlike poles of permanent magnets or electromagnets.

Attraction between the open core of an electromagnetic solenoid and a piece

of iron or a magnet.

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

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.

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.




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CHAPTER-2

HISTORY OF MAGLEV

Original patent (1941)

The first patent for a magnetic levitation train propelled by linear motors was

German Patent 707032, issued in June 1941.

A U.S. patent, dated 1 October 1907, is for a linear motor propelled train in

which the motor, below the steel track, carried some but not all of the weight of

the train. The inventor was Alfred Zehden of Frankfurt-am-Main, Germany.

Tsukuba, Japan 1985

HSST-03 wins popularity in spite of being 30km/h and a run of low speed in

Tsukuba World Exposition.

Okazaki, Japan 1987

JR-Maglev took a test ride at holding Okazaki exhibition and

runs




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Saitama, Japan 1988

HSST-04-1 exhibited it at Saitama exhibition performed in Kumagaya, and runs.

Best speed per hour 30km/h.

Yokohama, Japan 1989

HSST-05 acquires a business driver's license at Yokohama exhibition and carries

out general test ride driving. Maximum speed 42km/h.

The history of maximum speed record by a trial

run

• 1974 - West Germany - EET-01 - 230km/h

• 1975 - West Germany - Comet - 401.3km/h(by steam rocket propulsion)

• 1978 - Japan - HSST01 - 307.8km/h(by Supporting Rockets propulsion,

made in Nissan)

• 1978 - Japan - HSST02 - 110km/h

• 1979 - Japan - ML500 - 517km/h (no with passenger)

• 1987 - Japan - MLU001 - 400.8km/h(with passenger)

• 1988 - West Germany - TR-06 - 412.6km/h

• 1989 - West Germany - TR-07 - 436km/h

• 1993 - Germany - TR-07 - 450km/h

• 1994 - Japan - MLU002N-431km/h(no with passenger)

• 1997 - Japan - MLX01 - 550km/h (no with passenger)

• 1999 - Japan - MLX01 - 552km/h (with passenger)

• 2003 - Germany - TR-08 - 501km/h (with passenger)

• 2003 - Japan - MLX01 - 581km/h (with passenger)




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CHAPTER-3

Magnetically Levitated Trains (MAGLEV)

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 and minimum maintenance.

TECHNOLOGY AND WORKING OF MAGLEV TRAINS

Basically the construction of the maglev train depends on 3 different working

forces. They are,

LEVITATION FORCE

PROPULSION FORCE

LATERAL GUIDING FORCE




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1. LEVITATION FORCE

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.

The levitating force is the upward thrust which lifts the vehicle in the air.

There are 2 types of levitating systems

A.Electromagnetic suspension (EMS) uses the attractive magnetic force of a

magnet beneath a rail to lift the train up.

B.Electrodynamics suspension (EDS) uses a repulsive force between two

magnetic fields to push the train away from the rail.

A. ELECTROMAGNETIC SUSPENSION (EMS) SYSTEM

MAGLEV concept using EMS employs attractive force. In EMS system the

electromagnets are attached on the inside bottom of the casing that extend below and

then curves back up to the ferromagnetic rail or track. The rail is in the shape of

„T‟.When current is passed, the electromagnet is switched on, there is attraction

between the electromagnet and rail, and raise up to meet the rail. This levitates about

1/3 of an inch

(1 cm) above the guide way and keeps the train levitated even when it‟s not moving.

Other embedded guidance magnet keeps the train moving from side to side. The

electromagnet use feedback control to maintain a train at a constant distance from

the track, by controlling the attractive force by varying the current. There is no need

of wheels.




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Levitation System’s Power Supply

Batteries on the train power the system, and therefore it still functions without

propulsion.

The batteries can levitate the train for 30 minutes without any additional

energy.

Linear generators in the magnets on board the train use the motion of the train

to recharge the batteries.

Germany developed MAGLEV Train based on similar concept called Transrapid .

Germany has demonstrated that the maglev train can reach 300 mph with people

onboard.

B. ELECTRODYNAMIC SUSPENSION (EDS) SYSTEM

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.




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The gap between vehicle and guideway in the EDS-system is nearly 4 inches (10

cm), and is also regulated (by a null-flux system). . One potential drawback in using

the EDS system is that maglev trains must roll on rubber tires until they reach a

liftoff speed of about 62 mph (100 kph).

Japanese engineers say the wheels are an advantage if a power failure caused a

shutdown of the system.

Germany's Transrapid train is equipped with an emergency battery power supply.

The Japanese said that the EMS-attractive system gap was too narrow to account for

the hilly terrain of Japan, and Japan's occasional earthquakes.

A more advanced EDS-repulsive system, worked on by the Japanese (and

Americans), utilizes a U-shaped guideway, in which the vehicle nestles in between

the U-shaped guideway (this makes the vehicle very stable, it can't overturn). Coils

are implanted in the walls of the U- shaped guideway, called guidewalls. 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.




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INDUCTRACK

The Induct rack is a newer type of EDS that uses permanent room

temperature magnets to produce the magnetic fields instead of powered

electromagnets or cooled superconducting magnets. Induct rack uses a power source

to accelerate the train only until begins to levitate. If the power fails, the train can

slow down gradually and stop on its auxiliary wheels.

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.




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There are two Inductrack designs: Inductrack I and Inductrack II. Inductrack I is

designed for high speeds, while Inductrack II is suited for slow speeds. Inductrack

trains could levitate higher with greater stability. As long as it's moving a few miles

per hour, an Inductrack train will levitate nearly an inch (2.54 cm) above the track. A

greater gap above the track means that the train would not require complex sensing

systems to maintain stability.

Permanent magnets had not been used before because scientists thought that they

would not create enough levitating force. The Inductrack design bypasses this

problem by arranging the magnets in a Halbach array. The magnets are configured so

that the intensity of the magnetic field concentrates above the array instead of below

it. They are made from a newer material comprising a neodymium-iron-boron alloy,

which generates a higher magnetic field. The Inductrack II design incorporates two

Halbach arrays to generate a stronger magnetic field at lower speeds.

BENEFITS OF EMS-ATTRACTIVE AND EDS – REPULSIVE SYSTEMS

There are different benefits to the EMS-attractive and the EDS-repulsive system.

The EMS-attractive system has had more testing, and appears more ready to go. It

also does not require a secondary suspension system, which the EDS-repulsive

system does. But there are two features of the EDS system, which make it very

attractive and promising. First, the EDS-repulsive system employs superconducting

magnets (SCMs), so there is no resistance means no loss of energy through heat

dissipation. It has been estimated that superconducting magnets for maglev will only

have to be recharged after about 400 hours of use, or every 2 weeks, if the vehicle

ran continually. By contrast, electromagnets of the EMS-attractive system require a

continuous input of current to create the magnetic fields. However, the cryogenic

system uses to cool the coils can be expensive. Also, passengers with pacemakers

would have to be shielded from the magnetic fields generated by the

superconducting electromagnets.




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Second advantage of EDS-maglev is that it has a larger air gap than EMS-maglev,

meaning that the system should handle wind- gusts, or hilly terrain, or earthquakes,

or other disturbances, much more smoothly. It is also believed, that hypothetically,

EDS- maglev will be able to attain higher speeds in the long-run.

2. 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

2.1 PRINCIPLE OF LINEAR MOTOR

However, this raises a frequently asked question: where is the motor or engine

in the maglev system? There is a 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 onboard the vehicle; but on

occasion, in some systems, the roles can be reversed. This becomes important in the

propulsion system.




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Maglev vehicles are propelled primarily by one of the following 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.

2. A Linear Induction Motor (LIM): In which an electromagnet underneath the

vehicle induces current in an aluminum sheet on the guideway.

2.2 PROPULSION OF EMS SYSTEM

In the attractive-EMS system, electromagnetic attraction is also used to power

the train vehicle forward, but it uses a electromagnetic system dedicated for

propulsion and separate from the electromagnetic system used for levitation. For

propulsion purposes, there are ferromagnetic stator packets (with three-phase mobile

field windings) attached to the guideway. When activated, they attract the

electromagnet onboard the maglev. A three-phase current, of varying frequency, is

used, and generated through different stators in different segments of the track. The

stators that are excited are always just in front of the maglev vehicle. As the stators

are excited sequentially, the electromagnets onboard 'chase' the current forward

along the track, providing forward motion, or propulsion.




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The EMS-attractive system maglev surfs with its support magnets on the alternating

magnetic field generated in the roadway. The created electromagnetic wave is

actually a mobile or traveling electromagnetic wave. The EMS-attractive system is

sometimes labeled a "pull" system: the vehicle is pulled forward.

Braking is done by reversing the magnetic field. Some trains also have air

flaps, like airplanes, to slow down, as well as wheels that extend downward or

outward to the guideway for emergency braking in the unlikely event that everything

else fails.

2.3 PROPULSION OF EDS SYSTEM

The propulsion of the EDS-repulsive system can be described as "pull- then neutral-then push." (EDS-repulsive also usually uses a linear synchronous motor or a locally

commutated motor). In the EDS system, coils or an aluminum sheet in the guideway

are used for providing drive, although they also are different than the coils dedicated

for the function of levitation.




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3 .LATERAL GUIDING FORCE

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.

The levitation coils facing each other are connected under the guideway,

constituting a loop. When a running Maglev vehicle, that is a superconductingmagnet, displaces laterally, an electric current is induced in the loop, resulting in a

repulsive force acting on the levitation coils of the side near the train and attractive

force acting on the levitation coils of the side farther apart from the train. Thus, a

running train is always located at the center of the guideway.




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Working of Maglev:

A maglev train floats about 10mm above the guidway on a magnetic field. It ispropelled by the guidway itself rather than an onboard engine by changing

magnetic fields (see right).

Once the train is pulled into the next section the magnetism switches so that the

train is pulled on again.

The Electro-magnets run the length of the guideway.

Mechanism of Maglev Train




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CHAPTER-4

Advantages of Maglev:

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

2. Maintenance

There is very little maintenance because Due to the lack of physical

contact between the track and the vehicle, there is no rolling friction,

leaving only air resistance

3. Economic Efficiency

The powerful magnets demand a large amount of electricity to function

so the train levitates. What makes the maglev trains much more

expensive to build. Very costly to operate since it needs large magnets and a very

advanced technology and huge amount of electrical power.

Operating expenses are half of that of other railroads.

The linear generators produce electricity for the cabin of the train.

4. Environment

No 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




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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 small animals 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.

5. Speed

The highest speed achieved on the Shanghai track has been 501 km/h

(311 mph).

The highest speed achieved on the JR-Maglev has reached 581 km/h

(367 mph).

The highest speed achieved by any wheeled trains, the current TGV

speed record is 574.8 km/h, 357.0 mph.

6. Comfort

The ride is smooth while not accelerating.

But passengers traveling in a 250-mile-per-hour MAGLEV train will

feel much stronger gravitational forces in rounding an interstate curve

than will passengers in a car moving at 65 mi (105 km) per hour.

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




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CHAPTER-5

FUTURE EXPANSIONS

In the far future Maglev technology are hoped to be used to transport vast

volumes of water to far regions at a greater speed eliminating droughts.

Far more, space is an open door to maglev trains to propel space shuttle and

cargo into space at a lower cost. Artist‟s illustration of Star Tram, a

magnetically levitated low-pressure tube, which can guide spacecraft into the

upper atmosphere.

Scientists hope future technologies can get the train to operate at a 6000km/h,

since theoretically the speed limit is limitless. But still it‟s a long way to go.




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CONCLUSION

It‟s no longer science fiction, maglev trains are the new way of transportation in the

near future, just some obstacles are in the way, but with some researches nothing is

impossible.

With no engine, no wheels, no pollution, new source of energy, floating on air, the

concept has token tens of years to develop, just recently it‟s true capacities has been

realized.

Competing planes with speed, boats with efficiency, traditional trains with safety,

and cars with comfort, it seems like it isn't a fair fight.

References

www.ieee.com

www.chron.com

www.dbamanufacturing.com

www.singnet.com.sg

news.bbc.co.uk

The Official Transrapid Site- lots of information about Maglev

Japanese Technical Research Institute- Japanese projects

en.wikipedia.org

http://www.ieee.com/

http://www.chron.com/

http://www.dbamanufacturing.com/

http://www.singnet.com.sg/

http://www.singnet.com.sg/










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maglev report part 2 ashish

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