maglev

LIST OF FIGURES

SNo. Description of the figure Fig No. Page No

1 Introduction to “Maglev trains” Fig 1.1 2

2 Levitation by attraction Fig 3.2 5

3 Levitation by repulsion Fig 3.3 5

4 Using an IR emitter and detector set in straight manner

Fig 3.5 7

5 Using an IR emitter and detector set in angled manner

Fig 3.6 7

6 Using an ultrasonic emitter and detector set

Fig 3.7 8

7 Using one Hall effect sensor and two magnets

Fig 3.8.1 9

8 Using two Hall effect sensors and one magnet

Fig 3.8.2 9

9 Basic propulsion technique Fig 4.1 11

10 Horizontal flux canceling Fig 4.2.1 13

12 Vertical flux restoration Fig 4.2.2 15

13 About maglev train Fig 5.1 17

14 Japanese maglev train Fig 5.3.1 20

15 French “train a grand vitesse” Fig 5.3.2 22

16 German transrapid Fig 5.3.3

17 Spain (AVE trains) Fig 5.3.4

18 Guideway ( a structural model) Fig 5.4.3 (a)

19 A Japanese test track Fig 5.4.3 (b)

20 Block diagram of propulsion Fig 6.1.1 46

21 Block diagram of levitation Fig 6.1.2 47

22 Basic circuit diagram for levitation Fig 6.2.1 49

23 Power circuit for levitation Fig 6.2.2 51

24 Circuit diagram for propulsion Fig 6.2.3 53

25 Regulated power supply Fig 6.3 (a) 55

26 Block diagram of regulated power supply system

Fig 6.3 (b) 55

27 PCB for levitation Fig 6.4.1 58

28 PCB for propulsion Fig 6.4.2 59

29 Overview Fig 7.1 (a) 65

30 Cross section of the guideway beam and vehicle

Fig 7.1 (b) 67

31 vehicles Fig 7.5 74

CONTENTS

CHAPTER 1: INTRODUCTION..........................................................................1

CHAPTER 2: OBJECTIVE…………………………………………………...…3

CHAPTER 3: MAGNETIC LEVITATION……………………………......(4-10)

3.1 What is magnetic levitation........................................................5

3.2 Levitation by repulsion……………….......…………………....5

3.3 Levitation by attraction………………………………………...5

3.4 Earnshaw’s principle & Exceptions……………………………6

3.4.1 Quantum effects…………………………………………6

3.4.2 Feedback………………………………………………...6

3.4.3 Rotation…………………………………………………6

3.5 Using an IR emitter and detector set in straight manner………7

3.6 Using an IR emitter and detector set in angled manner……….7

3.7 Using an ultrasonic emitter and detector set…………………..8

3.8 Using a Hall effect sensor……………………………………10

3.8.1 Use of one Hall effect sensor with two magnets……….10

3.8.2 Use of two Hall effect sensors with one magnet……….10

CHAPTER 4: MAGNETIC PROPULSION………………………………(11-16)

4.1 Basic propulsion technique…………………………………...12

4.2 Magnetic propulsion.................................................................14

4.2.1 Horizontal flux canceling……………………………...14

4.2.2 Vertical flux restoration………………………………..15

CHAPTER 5: ABOUT MAGLEV TRAIN SYSTEM……………………(17-45)

5.1 Introduction of maglev train………………………………….18

5.2 History of maglev system…………………………………….18

5.2.1 Original patent………………………………………….18

5.2.2 Birmingham maglev………………………………...…18

5.2.3 Berlin maglev……………………………………….…19

5.3 Existing maglev system………………………………………21

5.3.1 Japanese high speed maglev (bullet train)…...................21

5.3.2 French train-a-grande-vitesse (TGV)...............................23

5.3.3 German transrapid (TR-07)……………………………..25

5.3.4 Spain (AVE trains)……………………………………...27

5.4 Type of technology used……………………………………...28

5.4.1 Electromagnetic suspension (EMS)….............................28

5.4.2 Electrodynamic suspension (EDS)..................................28

5.4.3 Guideway……………………………………………….29

5.5 Pros and cons of different technologies………………………30

5.6 Maglev Vs. conventional train………………………………..31

5.7 Advantages of maglev………………………………………...31

5.8 Economics…………………………………………………….36

5.9 Importance of maglev………………………………………...37

5.10 If maglev between Chennai and Bangalore…………………44

CHAPTER 6: OUR PROJECT…………………………………………….(46-64)

6.1 Block diagram………………………………………………..46

6.1.1 Block diagram for propulsion…………………………46

6.1.2 Block diagram for levitation…………………………..48

6.2 Circuit diagrams……………………………………………..50

6.2.1 Basic circuit diagram for levitation……………………50

6.2.2 Power circuit for levitation…………………………….52

6.2.3 Circuit diagram for propulsion………………………...54

6.4 Power supply………………………………………………...56

6.5 PCB diagram………………………………………………..59

6.5.1 PCB diagram for levitation…………………………..59

6.5.2 PCB diagram for propulsion………………………….59

6.6 Component list………………………………………………62

6.7 Problem arrived in project with solutions…………………...63

CHAPTER 7: APPLICATION ( M3 URBAN TRANSPORTATION

SYSTEM)…………………………………………………...(65-79)

7.1 Overview……………………………………………………65

7.2 Electromagnetic suspension and guidance.............................69

7.2.1 Permanent magnet EMS…………..............................70

7.2.2 Horizontal and vertical turns………………………...71

7.3 Linear motor propulsion…………………………………....71

7.4 Guideway...............................................................................73

7.5 Vehicles……………………………………………………..75

7.5.1 Issues involved in choosing vehicle size……………..75

7.5.2 Vehicle design for system……………………………77

7.6 Cost estimate………………………………………………..77

CHAPTER 8: SUGGESTIONS FOR FURTHER ENHANCEMENT IN

THIS PROJECT…………………………………………..(80-81)

CHAPTER 9: BIBLIOGRAPHY…………………………………………(82-84)

CHAPTER 10: APPENDIX……………………………………………….(85-90)

10.1 Appendix for chapter 4 ( magnetic propulsion)

10.2 Data sheet

10.3 Data sheet

CHAPTER 1

INTRODUCTION

Introduction (1)

CHAPTER 1 INTRODUCTION

Today's science knows only one way to achieve Real levitation, i.e. such that no energy

input is required and the levitation can last forever. The real levitation makes use of

diamagnetism, an intrinsic property of many materials referring to their ability to expel a

portion, even if a minute one, of an external magnetic field. Electrons in such materials

rearrange their orbits slightly so that they expel the external field This all technologies

were not in the picture till past few decades. This all has started when engineers in NASA

who were launching their satellites in space. The cost for launching was so expensive that

they started to think about an alternative approach to launch the satellites from earth.

Then they start working to manufacture a track that can achieve the speed equal to escape

velocity. For this they thought about this magnetic levitated and propelled system which

has no friction. This project failed for fewer reasons but the by product came out from

this thinking was the masterpiece ever created by human being i.e. MAGLEV TRAIN.

Maglev uses world's most advanced magnetic levitation technology to safely move

people and cargo reliably and comfortably. Maglev technology allows travelers to ride on

a cushion of air that reaches speeds up to 310 mph. The train is levitated and propelled

magnetically through a propulsion system located in the guide way that can either be

elevated or at grade. Passengers and cargo are efficiently transported in an

environmentally friendly and energy-efficient manner. Because the elevated guide way

can be built on existing freeway and railroad right-of-ways, land consumption and related

impacts are minimized. Additionally, Maglev operates more quietly than conventional

high-speed trains, has fewer impacts on adjoining communities and operation and

maintenance costs are significantly less than conventional high-speed rail. A landmark

for Maglev occurred in 1990 when it gained the status of a nationally-funded project. The

Minister of Transport authorized construction of the Yamanashi maglev test time,

Introduction (2)

targeting the final confirmation of Maglev for practical use. The new test line called the

Yamanashi Maglev Test Line opened on April 3, 1997 and is now being used to perform

running tests in Yamanashi Prefecture. In the same year, the Maglev vehicle MLX01 in a

three-car train set achieved world speed records, attaining a maximum speed of 531 km/h

in a manned vehicle run on December 12, and a maximum speed of 550 km/h in an

unmanned vehicle run on December 24. On March 18, 1999, MLX01 in a five-car train

set attained a maximum speed of 548 km/h. On April 14, 1999, this five-car train set

surpassed the speed record of the three-car train set, attaining a maximum speed of 552

km/h in a manned vehicle run. Travel has become an ever growing necessity in society

today. We depend upon it. However, travel today faces on-going hassles. In many

countries, new sources for travel are already being developed. A magnetic levitating

train, or maglev train, is one such source. In Japan and Germany, magnetically levitated

trains are currently being tested for future use. Japan’s maglev project has recently

become federally funded. Due to these problems, our society is constantly searching for

ways to improve transportation.

fig 1.1 Introduction to “Maglev trains ”

CHAPTER 2

OBJECTIVES

Objective (3)

CHAPTER 2 OBJECTIVE

In this project we have two objectives :

1) To study the basic techniques of levitation and propulsion of Magnetic Levitated train i.e. MAGLEV train. 2) On the basis of that study make a working models that can show levitation and propulsion principle.

CHAPTER 3

MAGNETIC LEVITATION

Magnetic levitation (4)

fig 3.2 Levitation by attraction

fig 3.3 Levitation by repulsion


CHAPTER 3 MAGNETIC LEVITATION

3.1 Magnetic levitation:

Magnetic levitation means levitate an object with the help of magnets. Magnetic

levitation of spinning permanent magnet tops was discovered by inventor Roy Harrigan

who patented it in 1983. Harrigan persisted in his e Rorts even after being told by several

physicists that permanent magnet levitation was impossible. Besides discovering spin

stabilization Harrigon designed a square dish shaped base that established a suitable

magnetic neld connguration, made a top with the right rotational inertia, mass and

magnetic moment, found the small capture volume and invented a means of moving the

spinning permanent magnet top to the right location. The parameter space for successful

levitation is quite small.

3.2 Levitation by repulsion:

Levitation by repulsion means we can levitate an object by repulsion property of

magnets i.e. similar poles always repel each other. If an object can be placed such that

similar poles of two magnets faces each other then they will repel each other and object

will levitate in period till they both get depart from each other (fig 3.2).

3.3 Levitation by attraction:

Levitation by attraction means we can levitate an object by attraction property of

magnets i.e. opposite poles always repel each other. If an object can be placed in such

manner that opposite poles of two magnets faces each other then they will attract each

other and object will levitate in period till they both get stuck to each other (fig 3.3).


3.4 Earnshaw’s principle & exceptions:

A theorem due to Earn Shaw proves that “it is not possible to achieve static

levitation using any combination of fixed magnets and electric charges”. Static levitation

means stable suspension of an object against gravity. There are, however, a few ways to

levitate by getting round the assumptions of the theorem. In case you are wondering,

none of these can be used to generate anti-gravity or to fly a craft without wings or jets.

This theorem even applies to extended bodies, which may even be flexible and

conducting so long as they are not diamagnetic. They will always be unstable to lateral

rigid displacements of the body in some direction about any position of equilibrium.

3.4.1 Quantum effects:

Technically any body sitting on a surface is levitated a microscopic distance above

it. This is due to electromagnetic intermolecular forces and is not what is really meant by

the term “levitation”. Because of the small distances, quantum effects are significant but

Earnshaw’s theorem assumes that only classical physics is relevant.

3.4.2 Feedback:

If we can detect the position of an object in space and feed it into a control system

that can vary the strength of electromagnets that are acting on the object, it is not difficult

to keep it levitated. We just have to program the system to weaken the strength of the

magnet whenever the object approaches it and strengthen when it moves away. These

methods violate the assumption of Earn Shaw’s theorem that the magnets are fixed.

Electromagnetic suspension is one system used in magnetic levitation trains (maglev)

such as the one at Birmingham airport, England.

3.4.3 Rotation:

Surprisingly, it is possible to levitate a rotating object with fixed magnets. The


levitron is a commercial toy that exploits the effect, invented by Roy Harrison in

1983. The spinning top can levitate delicately above a base with a careful arrangement of

magnets so long as its rotation speed and height remains within certain limits. Ceramic

materials are used to prevent induced currents which would dissipate the rotational

energy.

fig 3.5 Using an IR emitter and fig3.6 Using an IR and detector set in detector set in straight manner angled manner

3.5 Using an IR emitter and detector set in straight manner

We can use an infrared light emitter and detector set up so that the ball will block

only a certain portion of the light. If the infrared is totally blocked, the ball is too close. If

the infrared isn’t blocked at all, the ball is too far away. If just half of the infrared is

blocked, the position of the ball is just right.

3.6 Using an IR emitter and detector set in angled manner

We can use an infrared light emitter and detector, but aimed to reflect off of the

surface of the ball. Again, if no infrared bounces back, the ball is too far away. If too

much infrared bounces back, it is too close. If there is just the right amount of infrared,

the position of the ball is just right.

http://www.levitron.com/


fig 3.7 Using an ultrasonic emitter and detector set

3.7 Using an ultrasonic emitter and detector set

We can use an ultrasonic emitter and detector, used in some cameras to do the

automatic focusing. If this were placed under the ball, the strength of the signal would tell

us how far away the ball is located. The circuit would be set to command a specific

distance. When ultrasonic emitter sends the signal it will be received by the receiver after

striking the object. We can make a watch by calculating the average time for the whole

distance covered. If after a certain time limit is fixed then if the object is going far from

the magnet then average time will increase and will decrease if the object is getting closer

to the magnet. By monitoring average time we will be able to detect the position of the

object and hence we can maintain it in optimum.


fig 3.8.1 Using one Hall effect sensor and two magnets

fig 3.8.2 Using two Hall effect sensors and one magnet


3.8 Using a Hall effect sensor :

3.8.1 Using one Hall effect sensor and two magnets:

If the object could contain two magnets, one could be used with the electromagnet

for the suspension, and the other could be placed at the bottom of the object, close to

where we would place a hall effect device. This device could be used to indicate how

close the bottom magnet is, so we would know how far away the object is from the

electromagnet. The object would have to be a stiff item, not spongy.

3.8.2 Using two Hall effect sensors and one magnet

We can use two Hall effect devices, one mounted onto each end of the

electromagnet. When no permanent magnet is near, no matter how much current is in the

electromagnet, the two Hall effect devices' signals would cancel each other out. When a

magnet gets closer to one, then the difference between the two signals starts to increase.

So, it is this difference in signals that we could monitor and control.

CHAPTER 4

MAGNETIC PROPULSION

Magnetic propulsion (11)

fig 4.1 Basic propulsion technique


CHAPTER 4 MAGNETIC PROPULSION

4.1 Basic propulsion technique:

In maglev trains there is no need of using conventional fuel like we are using in

vehicles of today’s world. Instead of this we will us attraction and repulsion property of

magnets in horizontal manner. When vehicle will be in straight parallel combination of

magnet then the pole at the front will always be attracted by opposite polarized magnets

on the guideway. Similarly the magnet at the back of the vehicle will always be repelled

by the same polarized magnet on the guideway (fig 4.1). In the figure this technique is

clearly reflected. In the figure vehicle have two sets of magnet in it in parallel opposite

combination. When vehicle launched in the guideway its left hand set of magnet which is

shown as the upper part in the vehicle gets attracted be the oppositely polarized pole

similarly its second half get repelled by the similarly polarized magnet. Similarly the

magnet set on the right half which is shown as bottom one’s will be attracted and repelled

by the opposite and similarly polarized magnets respectively. Hence by this method of

repulsion and attraction vehicle start moving in the forward direction. This operation can

be repeated in opposite direction by applying the same technique in reverse procedure. As

automobiles use conventional fuel, they produce pollution but as there is no such type of

consumption of fuel then there will be no pollution.


(fig 4.2.1) (fig 4.2.1a)

(Phase A) (Phase B) (Phase C) (Phase D)

(fig 4.2.1 b) (fig 4.2.1 c)

(fig 4.2.1 d)

fig 4.2.1 Horizontal flux canceling


4.2 Magnetic propulsion

For magnetic propulsion we need a huge structure of coils layered on top of each

other built into the track. These coils are shaped similar to a figure 8. The reasons they

are shaped like a figure 8 is to give them a “Null Flux” design. Null flux means that the

flux in the direction of travel produces a net force of zero on the train. In order to explain

the electrodynamic suspension completely; we must break the system down and look at

in a different way. The flux through the levitation and guidance coils due to the train’s

B-field must be categorized into two different parts. The first part of the flux we will

analyze is called horizontal flux canceling. The second part of flux is called vertical

flux restoration.

4.2.1 Horizontal flux canceling:

The train’s equilibrium position is at the vertical midpoint of the levitation and

guidance coil. The flux in the top and bottom half of the coil is the same (fig4.2.1).

However, the train will not run at equilibrium instantaneously. The train’s

electromagnetic coils will be offset toward the bottom half of the guidance and levitation

coils. In this case, the flux through the levitation and guidance coils must be analyzed

separately. The horizontal flux (fig 4.2.2) is the larger in the bottom coil. As the train

moves, the horizontal flux changes. The changing flux induces a current in the bottom

coil. As the coil is subjected to different B-fields, we must analyze the current using

Lenz’s law (fig 4.2.2 a.). Given the changing flux situation we can analyze the direction

of the induced current (fig 4.2.2 b).From the directions of the induced currents, we can

determine the direction of the B-fields (fig 4.2.2 c).Since the B-fields from the induced

currents changing at every half-way point of the trains electromagnets, the horizontal

forces will cancel each other out (fig 4.2.2 d).


(PHASE A) (PHASE B)

(fig 4.2.2 a) (fig 4.2.2 b)

(fig 4.2.2 c) (fig 4.2.2 d)

(fig 4.2.2 e)

fig 4.2.2 Vertical flux restoration

4.2.2 Vertical flux restoration:

The vertical force need to levitate the train is due to the vertical flux component.


The train’s optimum equilibrium position is at the vertical midpoint of the levitation and

guidance coil. At that point, the flux in the top and bottom half of the coil is the same

(phase A). The train’s significant mass and gravity however, create a downward force,

driving the train closer to the guide way (phase B).If the B-field produced by the train’s

magnet is into the page the induced current will be clockwise (fig 4.2.2 a).If the B-field

produced by the train is into the page, the induced current will be counterclockwise (fig

4.2.2 b).Two components of the vertical flux are changing. By analyzing each half of the

levitation and guidance coil, we can more effectively understand what happens. The

bottom half of the coils in both phases are shown below (fig 4.2.2 c).In phase B, the flux

of the bottom coil increases in area by a factor of (sw * dy) where sw is the width of the coil.

Therefore an opposing induced current is generated. The top half of the coils in both

phases are shown below (fig 4.2.2 d).In phase B, the flux of the bottom coil decreases in

area by a factor of (sw * dy) where sw is the width of the coil Therefore an opposing induced

current is generated. When you analyze the entire guidance and levitation coil, the

induced current in the top half is traveling in the same direction as the bottom half (fig

4.2.2 e).This induced current will set up a B-field in the bottom half of the coil that is

opposite in direction of the superconducting magnet’s B-field. In turn, those same

current sets up a B-field that is in the same direction as in the top half of the coil. The B-

field on the bottom will cause the train to be pushed upward, and the B-field in the top

will cause the train to be pulled upward. These forces allow the train to stay levitated at

about the same height for entire time except for its initial acceleration period. During the

train’s initial acceleration period, the train is not moving fast enough to levitate it. The

train has wheels, which it runs on until it reaches approximately 65mph. This secondary

suspension system is very important because without it the train would not be able to start

levitating. The wheels hold the train about four to six inches off of the track placing the

magnets on the train just below the center of the guidance-levitation coils.

CHAPTER 5

ABOUT MAGLEV TRAIN SYSTEM

About Maglev train system (17)

fig 5.1 About maglev train


CHAPTER 5: ABOUT MAGLEV TRAIN SYSTEM

5.1 Introduction:

Magnetic levitation (Maglev) is an advanced technology in which magnetic forces

lift, propel, and guide a vehicle over a guideway (usually elevated). Utilizing state-of-

the-art electric power and control systems, this configuration eliminates physical

contact between vehicle and guideway and permits cruising speeds of up to 300 mph,

somewhat higher than the speed of conventional high-speed rail service. Because of its

higher speed, Maglev may be able to offer competitive trip-time savings to auto and

aviation modes in the 40- to 600-mile travel markets–a needed travel option for the 21st

century.

5.2 History of maglev system:

5.2.1 Original patent:

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

5.2.2 Birmingham maglev:

The world’s first commercial automated system was a low-speed maglev shuttle

that ran from the airport terminal of Birmingham International Airport (UK) to the

nearby Birmingham International railway station from 1984 to 1995. Based on

http://en.wikipedia.org/wiki/1995


http://en.wikipedia.org/wiki/Birmingham_International_railway_station

http://en.wikipedia.org/wiki/Birmingham_International_Airport_(UK)


http://en.wikipedia.org/wiki/October_1


experimental work, length of the track was 600 m, and trains “flew” at an altitude of 15

mm.

5.2.3 Berlin maglev:

In West Berlin, the M-Bahn was built in the late 1980s. It was a driverless maglev

system with a 1.6 km track connecting three stations. Testing in passenger traffic

started in August 1989, and regular operation started in July 1991. Although the line

largely followed a new elevated alignment, it terminated at the U-Bahn station

Gleisdreieck, where it took over a platform that was then no longer in use; it was from a

line that formerly ran to East Berlin in 1992.

http://en.wikipedia.org/wiki/East_Berlin

http://en.wikipedia.org/wiki/Berlin_U-Bahn



http://en.wikipedia.org/wiki/1980s

http://en.wikipedia.org/wiki/M-Bahn

http://en.wikipedia.org/wiki/West_Berlin


fig 5.3.1 Japanese maglev train

About maglev train system (21)

5.3 Existing maglev system :

5.3.1 Japanese high speed maglev (bullet train):

The Central Japan Railway Company plans to begin building a high-speed line

from Tokyo to Osaka on a new route (including the Yamanashi test section) starting in

1997. This will provide relief for the highly profitable Tokaido Shinkansen, which is

nearing saturation and needs rehabilitation. To provide ever improving service, as well

as to forestall encroachment by the airlines on its present 85 percent market share,

higher speeds than the present 171 mph (76 m/s) are regarded as necessary. Although

the design speed of the first generation maglev system is 311 mph (139 m/s), speeds up

to 500 mph (223 m/s) are projected for future systems. Repulsion maglev has been

chosen over attraction maglev because of its reputed higher speed potential and because

the larger air gap accommodates the ground motion experienced in Japan's earthquake-

prone territory. The design of Japan's repulsion system is not firm. A 1991 cost

estimate by Japan's Central Railway Company, which would own the line, indicates

that the new high-speed line through the mountainous terrain north of Mt. Fuji would

be very expensive, about $100 million per mile (8 million yen per meter) for a

conventional railway. A maglev system would cost 25 percent more. A significant part

of the expense is the cost of acquiring surface and subsurface ROW. Knowledge of the

technical details of Japan's high-speed Maglev is sparse. It will have superconducting

magnets in bogies with sidewall levitation, linear synchronous propulsion using

guideway coils, and a cruise speed of 311 mph (139 m/s).


fig 5.3.2 French “train a grand vitesse”


5.3.2 French Train a Grande Vitesse (TGV) :

The French National Railway’s TGV is representative of the current generation

of high-speed, steel-wheel-on-rail trains. The TGV has been in service for 12 years on

the Paris-Lyon (PSE) route and for 3 years on an initial portion of the Paris-Bordeaux

(Atlantique) route. The Atlantique train consists of ten passenger cars with a power car

at each end. The power cars use synchronous rotary traction motors for propulsion.

Roof mounted pantographs collect electric power from an overhead catenary. Cruise

speed is 186 mph (83 m/s). The train is nontilting and, thus, requires a reasonably

straight route alignment to sustain high speed. Although the operator controls the train

speed, interlocks exist including automatic over speed protection and enforced braking.

Braking is by a combination of rheostat brakes and axle-mounted disc brakes. All axles

possess antilock braking. Power axles have anti-slip control. The TGV track structure is

that of a conventional standard-gauge railroad with a well-engineered base (compacted

granular materials). The track consists of continuous-welded rail on concrete/steel ties

with elastic fasteners. Its high-speed switch is a conventional swing-nose turnout. The

TGV operates on pre-existing tracks, but at a substantially reduced speed. Because of

its high speed, high power, and antiwheel slip control, the TGV can climb grades that

are about twice as great as normal in U.S. railroad practice and, thus, can follow the

gently rolling terrain of France without extensive and expensive viaducts and tunnels.


fig 5.3.3 German transrapid


5.3.3 German transrapid (TR-07) :

The German TR07 is the high-speed Maglev system nearest to commercial

readiness. If financing can be obtained, ground breaking will take place in Florida in

1993 for a 14-mile (23 km) shuttle between Orlando International Airport and the

amusement zone at International Drive. The TR07 system is also under consideration

for a high-speed link between Hamburg and Berlin and between downtown Pittsburgh

and the airport. As the designation suggests, TR07 was preceded by at least six earlier

models. In the early seventies, German firms, including Krauss-Maffei, MBB and

Siemens, tested full-scale versions of an air cushion vehicle (TR03) and a repulsion

maglev vehicle using superconducting magnets. After a decision was made to

concentrate on attraction maglev in 1977, advancement proceeded in significant

increments, with the system evolving from linear induction motor (LIM) propulsion

with wayside power collection to the linear synchronous motor (LSM), which employs

variable frequency, electrically powered coils on the guide way. TR05 functioned as a

people mover at the International Traffic Fair Hamburg in 1979, carrying 50,000

passengers and providing valuable operating experience. The TR07, which operates on

19.6 miles (31.5 km) of guideway at the Emsland test track in northwest Germany, is

the culmination of nearly 25 years of German Maglev development, costing over $1

billion. It is a sophisticated EMS system, using separate conventional iron-core

attracting electromagnets to generate vehicle lift and guidance. The vehicle wraps

around a T-shaped guideway. The TR07 guideway uses steel or concrete beams

constructed and erected to very tight tolerances. Control systems regulate levitation and

guidance forces to maintain an inch gap (8 to 10 mm) between the magnets and the iron

“tracks” on the guideway. Attraction between vehicle magnets and edge-mounted

guideway rails provide guidance. Attraction between a second set of vehicle magnets


and the propulsion stator packs underneath the guideway generate lift. The lift magnets

also serve as the secondary or rotor of a LSM, whose primary or stator is an electrical

winding running the length of the guideway. TR07 uses two or more nontilting vehicles

in a consist. TR07 propulsion is by a long-stator LSM. Guideway stator windings

generate a traveling wave that interacts with the vehicle levitation magnets for

synchronous propulsion. Centrally controlled wayside stations provide the requisite

variable-frequency, variable-voltage power to the LSM. Primary braking is

regenerative through the LSM, with eddy-current braking and high-friction skids for

emergencies. TR07 has demonstrated safe operation at 270 mph (121 m/s) on the

Emsland track. It is designed for cruise speeds of 311 mph (139 m/s).

fig 5.3.4 Spain (AVE trains)


5.3.4 Spain (AVE trains):

The section of high speed line runs from Seville to Madrid where AVE trains run

(which are TGVs exported to Spain) and Talgo trains run. The advantage of Talgo trains

is that they can run on Spanish Broad gauge railway and high speed line (standard guage)

as the wheels are designed to change. Therefore Talgo services can use the high speed

line for a fast run and then go on for connections on conventional line. The Talgo has a

top speed of 220km/h or 138mph. The AVE TGV has a top speed of 300km/h or

138mph.

fig 5.4.3 (a) Guideway ( a structural model)


fig 5.4.3 (b) A Japanese test track

5.4 Type of technology used :

In maglev basically two type of technology are in use:

Electromagnetic suspension (EMS)

Electrodynamic suspension (EDS).

5.4.1 Electromagnetic suspension (EMS):

In current EMS system, the train levitates above a steeel rail while

electromagnets attach to the train are oriented toward the rail from below. The

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

the track.EMS uses the attractive magnetic force of magnet beneath a rail to life the

train up.

5.4.2 Electrodynamic suspension (EDS):

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. The magnetic field in

http://en.wikipedia.org/wiki/Electromagnet


the train is produced by either electromagnets as in JR-Maglev or by an array of

permanent magnets. The repulsive force in the track is created by an Electromagnetic

induced magnetic field in wires or other conducting strips in the track. 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. Propulsion coils on the guideway are used to exert a force on

the magnets in the train and make the train move forwards. 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 create a force moving the train forward.

5.4.3 Guideway:

Like the conventional trains, maglev trains must also follow a track, called a

guide-way. In this system, the only forces experienced by the train are air resistance

and momentum. Therefore, there needs to be a system that keeps the train from

running into the sides of the guide-way or leaving the track all together. This system

is called the guidance system. The way it works is if the train shifts off center, it is

closer to one set of guidance-levitation coils. The difference in the B-fields creates a

restoring force that pushes the train back toward the center of the track.


5.5 Pros and cons of different technologies:

TECH PROS CONS

EMS

EDS

Magnetic fields in 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.

Onboard magnets and large

margin between rail and train

enable highest recorded train

speeds (581 km/h) and heavy

load capacity; has recently

demonstrated (Dec 2005)

successful operations using

high temperature

superconductor in its onboard

magnets, cooled with

inexpensive liquid nitrogen.

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

Strong magnetic fields onboard

the train would make the train

inaccessible to passengers with

pacemakers or magnetic data

storage media such as hard

drives and credit cards,

necessitating the use of magnetic

shielding; vehicle must be

wheeled for travel at low speeds;

system per mile coststill

considered prohibitive; the

system is not yet out of prototype

phase.

http://en.wikipedia.org/wiki/Prototype

http://en.wikipedia.org/wiki/Wheeled

http://en.wikipedia.org/wiki/Magnetic_shielding

http://en.wikipedia.org/wiki/Magnetic_shielding

http://en.wikipedia.org/wiki/Pacemaker

http://en.wikipedia.org/wiki/Nitrogen

http://en.wikipedia.org/wiki/Onboard


5.6 Maglev Vs. conventional train;

Due to the lack of physical contact between the track and the vehicle, there is

no rolling friction, leaving only air resistance (although maglev trains also experience

electromagnetic drag, this is relatively small at high speeds).

Maglev’s can handle high volumes of passengers per hour (comparable to

airports or eight-lane highways) and do it without introducing air pollution along the right

of way. Of course, the electricity has to be generated somewhere, so the overall

environmental impact of a maglev system is dependent on the nature of the grid power

source.

The weight of the large electromagnets in EMS and EDS designs are 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.

Due to its high speed and shape, the noise generated by a maglev train is similar

to a jet aircraft, and is considerably more disturbing than standard steel on steel intercity

train noise. A study found the difference between disturbance levels of maglev and

traditional trains to be 5dB (about 78% noisier).

5.7 Advantages of maglev:

The ultimate implementation of maglev technology in regional and national

networks would reduce air and highway congestion, air pollution, and petroleum use. The


http://en.wikipedia.org/wiki/Train

http://en.wikipedia.org/wiki/Electromagnet

http://en.wikipedia.org/wiki/Environmental_concerns_with_electricity_generation

http://en.wikipedia.org/wiki/Environmental_concerns_with_electricity_generation

http://en.wikipedia.org/wiki/Right-of-way_(railroad)

http://en.wikipedia.org/wiki/Right-of-way_(railroad)

http://en.wikipedia.org/wiki/Air_pollution

http://en.wikipedia.org/wiki/Friction

advantages of a magnetically levitated (maglev) train over existing conventional high

speed ground transport systems and air travel:

High speed: -

Since lift, guidance, and propulsion occur without physical contact, speeds in

excess of 220 meters per second (800 kmph.) are well within the technological limits.

Furthermore, because magnetic drag is small at high speeds, only aerodynamic drag

consumes appreciable energy. Limiting the top speed of maglev is a cost trade-off

decision, not a physical or engineering limit. Maglev is also capable of rapid

acceleration/ deceleration and can climb hills with gradients of up to 10%, due to its

lighter weight.

Reduction in transit time: -

Maglev offers the advantage of railways by getting rid of waiting times in airports

for check-in, boarding etc., while offering high speed transit; thereby reducing the total

time for point to point transit.

Save oil: -

Electrically powered, maglev will be independent of petroleum-based fuels.

Low energy consumption: -

Maglev’s energy intensity (energy/seat-meter) ranges from one-seventh to one-

quarter of the efficient Boeing 737-300 for a 200 to 1,000 kilometre trip. Applying

electrical conversion efficiencies of modern power plants, maglev still consumes only


one-quarter to one-half the total energy of a 737-300. The high energy efficiency also

stems from the fact that only selective portions of the tracks need be 44nergized for

propulsion.

High Capacity: -

Maglev guideways achieve very high capacity of 12,000 passengers per hour in

each direction. An equivalent air capacity would be 60 Boeing 767’s per hour departing

in each direction at 1-minute intervals. Comparable highway traffic would require about

10 full lanes (5 lanes per direction).

Low Wear and Maintenance: -

By nature, maglev requires no physical contact between vehicle and guideway.

Lift and guidance forces are distributed over large areas, resulting in low contact stresses.

In contrast, high-speed rail experiences high stresses from wheel-rail contact (up to

70,000 psi) advantages of a magnetically levitated (maglev) train over existing

conventional high speed ground transport systems and air travel) and power transfer

resulting in frequent maintenance operations. Also, maglev allows significant reduction

in vehicle weight, because propulsion does not require physical contact. This in turn

reduces maintenance costs by up to 70%.

Modest Land Requirements: -

Land requirements for maglev stations will be very modest because the vehicles

are narrow. Furthermore, maglev’s elevated dual guideways have small footprints and

can be located along existing rail and highways. Maglev guideways can be elevated or


constructed at-grade. Elevated tracks have the advantage of being immune to collisions

with animals/ humans straying on the track. Land required for maglev will be lesser than

that for expressways or normal rail.

GUIDEWAY ROAD WIDTH

ft(m)

AREA ft2 (m2

4 LANE FREEWAY 98(30) 1070(100)

NORMAL RAIL(2-GUIDEWAY) 46(14) 430(40)

TRANSRAPID(2-GUIDE WAY) 40(12) 246(23)

Minimum turning radius :-

Maglev trains have an added advantage that the turning radius may be minimized

The stable turning radius varies as the square of the velocity, and is proportional to the

weight. A maglev train runs at a specific velocity with minimum contact, allowing tracks

to be banked at very tight radii.

Safety: -

Maglev vehicles operate safely under more extreme weather conditions and with

less maintenance. Maglev concepts offer exceptional derailment protection when

compared with high-speed rail systems. Large-gap maglev systems, in particular, will be

much more tolerant of guideway displacements than high-speed rail. The Transrapid is

designed with a "safe hovering" concept to ensure that the vehicle will come to a stop

only at a location where auxiliary power and means of evacuation are provided. The

vehicle will not proceed unless it is able to reach the next safe location independently of

guideway power. For this purpose, the vehicle has the minimum of 7.5 minutes reserve


electricity stored in the on board batteries. In the case of emergency, it has primary and

secondary braking systems. The brakes are magnets, which create a disruptive magnetic

field by interacting with the guideway, there by reducing speed. The vehicle then slides

along on its skids (friction coefficient 0.1) until it comes to a halt. The vehicles are

constructed from non-combustible materials.

Environmental issues: -

Maglev systems will complement existing transportation systems--and with

significantly less environmental impact than other modes.The Transrapid produces no

site-specific gas or liquid pollution. However, electrical generation creates large amounts

of pollution at electrical generation plants. The amount of pollution is a function of the

generation process and the amount of energy needed. Comparison of emissions in

milligram/seat km for various transportation systems is shown in the following table.

IN Kms CO NO2 SO2 CH CO2

Transrapid 200km 2.0 3.5 7.1 0.20 11,000

300km 2.8 11.7 3.7 0.27 15,000

400km 3.9 16.4 13.5 0.37 21,000

Airbus A 320 <600km 225 449 44 17 139,000

Automobile with catalytic converter 510 132 12 42 71,000

The result shows that the Transrapid has fewer emissions than Airbus or automobile.


Low magnetic fields: -

Maglev designs achieve static magnetic fields of less than 1 gauss (about twice

the earth's field) in passenger seating areas, with little cost or weight penalty.

Low noise levels:

At low speeds : Maglev avoids the major noise sources of high-speed rail

namely wheel-rail contact and pantograph-catenary contact, and can be

operated in urban areas.

For example, TR07 can travel about 25 percent faster than existing high-speed rail trains

before reaching the peak noise restrictions of 80 to 90 dBa.

At high speeds : Noise due to aerodynamic drag predominates over wheel-rail

contact at high speeds. Data indicate that even at high speeds maglev is 5 to 7

dBa quieter than high-speed rail.

Compatible: -

Maglev networks can interconnect with existing air and highway networks,

reducing air and highway congestion and extending the life of highways and air facilities.

5.8 Economics :-

The Shanghai maglev cost 9.93 billion Yuan (US$1.2 billion) to build. This total

includes infrastructure capital costs such as manufacturing and construction facilities, and


operational training. At 50 Yuan per passenger and the current 7,000 passengers per day,

income from the system is incapable of recouping the capital costs (including interest on

financing) over the expected lifetime of the system, even ignoring operating costs.

China aims to limit the cost of future construction extending the maglev line to

approximately 200 million Yuan (US$24.6 million) per kilometer. These costs compare

competitively with airport construction (e.g., Hong Kong Airport cost US$20 billion to

build in 1998) and eight-lane Interstate highway systems that cost around US$50 million

per mile in the US. While high-speed maglevs are expensive to build, they are less

expensive to operate and maintain than traditional high-speed trains, planes or intercity

buses. Data from the Shanghai maglev project indicates that operation and maintenance

costs are covered by the current relatively low volume of 7,000 passengers per day.

Passenger volumes on the Pudong International Airport line are expected to rise

dramatically once the line is extended from Longyang Road metro station all the way to

Shanghai's downtown train depot. The proposed Chūō Shinkansen line is estimated to

cost approximately US$82 billion to build. The only low-speed maglev (100 km/h)

currently operational, the Japanese Linimo HSST, cost approximately US$100

million/km to build. Besides offering improved O&M costs over other transit systems,

these low-speed maglevs provide ultra-high levels of operational reliability and introduce

little noise and zero air pollution into dense urban settings. As maglev systems are

deployed around the world, experts expect construction costs to drop as new construction

methods are perfected and councils were supportive. Some Government finance was

provided and because of sharing work, the cost per organization was not high.

5.9 Importance of maglev’s:

Importance of maglev can be easily understood by the following points discussed

below.

http://en.wikipedia.org/wiki/Dense

http://en.wikipedia.org/wiki/Linimo

http://en.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen#Costs

http://en.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen

http://en.wikipedia.org/wiki/Interstate_highway

http://en.wikipedia.org/wiki/Hong_Kong_Airport


5.9.1 Cost:

The total lifecycle cost analysis is the sum of four major categories:

Research and Development Cost

The following aspects must be looked into:

Conceptual research

Prototype and test guideway construction

Control systems research

Safety features

A proposal for a maglev project in Virginia puts this as $3.5 billion. The recently

constructed Shanghai test track cost a total of $1.2 billion (Rs. 6000 crores) for a track 30

km. long. This would be a minimum figure, considering that most of the technology was

supplied at highly subsidised rates by the German Transrapid Inc. the research will costs

around Rs. 6,000 crores.

Production and Construction Cost

These costs would include,

Industrial engineering, which includes production and manufacturing engineering

Guideway construction

Maintenance and control centre facilities

Guideway costs are highly dependent on the location of the particular project, the

nature of the terrain and the degree of urbanisation, and are very difficult to estimate


offhand.The estimated cost, according to the Transrapid system (Germany), is $6.25

million (Rs. 32 crores) per km for a single-track guideway. The Shanghai Hangzhou line

in China is estimated to cost $20 million per km. Guideway costs are about 65% of the

total, i.e. $13 million per km. This is about the same as the German estimate of $12.5

million per km. for a double track line.

At this cost, a Chennai-Bangalore line (360 km. + 40 km for double track) would

cost around Rs. 12,800 crores.

Indian Railways estimates the total cost of a proposed high-speed track between

Ahmedabad and Mumbai (approx. 550 km) as Rs. 20,000 to 30,000 crores . This

would amount to Rs. 45 – 50 crores per km.

Delhi Metro, Phase I and II are expected to cost around Rs. 170 – 200 crores per

km. This is extremely high as compared to other projects, probably because it is

an underground system in an urban area.

The Konkan Railway when completed in 1996 had cost around Rs. 4,000 crores at

around Rs. 5.3 crores per km.

The Mumbai – Pune Expressway (total length of 95 km.) has been completed at a

cost of Rs. 1630 crores (around 16 crores per km.)

Vehicle cost

The following costs would be taken into consideration:


Engineering costs

Material – a fire resistant, non-magnetic and lightweight material that can

withstand high speeds.

Cost of superconducting magnets and refrigeration facilities

Construction costs

The AP Metro project will import coaches at Rs. 5.25 crores per coach.The Virginia

project estimate is $ 50,000 (Rs. 25 lakh). per seat. A coach of 100 passengers each

would cost Rs. 25 crores. If 5 trips are to be run, we would need only two trains of, say,

10 coaches each running back and forth. This would cost Rs. 500 crores.

Land cost:

Land costs are dependent on the particular routing and topography. Existing

expressway lands may be used since the maglev does not require much ground area if it is

elevated, however there may be serious speed penalties because of the presence of

curves. In any case, the land costs represent only a small fraction of the overall

construction costs. (The Delhi Metro land acquisition costs were 8% of the total project

cost. This works out to Rs. 13 crores per km. So the Bangalore Chennai line would cost

Rs. 4700 crores. However costs along the Bangalore-Chennai route would be far lower

than this. So we shall neglect this for the time being). The total capital costs: Rs. 18,300

crores. (Transrapid + Virginia estimate). It may be noted here that there is a proposal to

extend the Shanghai maglev track by a length of 300 km. at a cost of $5 billion. (Rs.

25,000 crores).


Operation and Maintenance Costs:

Power supply / fuel

Training of personnel for operation and maintenance

Staff costs

Spares and repairs

Diagnostic equipment

Customer facilities like ticketing, parking, etc.

South Central Railway spends Rs. 2250 crores a year on operational costs . The

total track length is 7102 km. Therefore the operation and maintenance cost is around

0.32 crores/year/km. Around 30% of this spent on staff costs. Fuel costs total 15%. The

maglev efficiency should reduce fuel costs by as much as 50%.Operation Cost: Rs. 120

crores per year (without considering superior maglev efficiency). However, the maglev is

about 30% more efficient on fuel consumption (conservative), and the maintenance costs

are also reduced by about 50%.Therefore, operating costs would be about Rs. 84

crores/year.

Retirement and disposal cost :-

Recycling of material

Transportation and disposal of unusable materials.

Revenues:-

Ticketing: Pricing would be competitive when compared to automobile or air

travel, while being slightly higher than conventional rail travel.


Parking fees at rail stations

Freight transport

Scrap disposal

Timeline:-

Break even point:

At the present cost and ridership estimates, the maglev track should make an

annual profit of Rs.29.7 crores. At this rate, it would take an impossible 600 years to

recover the initial capital. However, things to be considered are the escalation in costs

due to inflation and the increase in ridership due to an increase in population and further

development. The rate of inflation in India based on the wholesale price index has been

about 5.3% (on an average) for the past five years. Assuming the same rate, cost prices

would increase by 67% by the end of the next ten years. But, the revenue generated will

also go up by the same amount due to higher pricing, which means that the annual profit

would be Rs. 49.7 crores. The population growths in Bangalore for the periods 1981-91

and 1991-01 have been 38.44% and 34.80% respectively. The corresponding numbers in

Chennai have been 17.24% and 9.26%. With the population growing at such a rapid rate

in Bangalore, and considering rapid development, we can expect an increase of about

35% in the maglev ridership. After these considerations, the annual profits would

Stage Years

Research and development 1 to 5

Prototype construction and experimentation 4 to 8

Construction (in stages) 6 to 14

Open to public 8 to 10


increase to about Rs. 49.7 cr. X 1.35 = Rs. 67.1 crores per year. The time required to

recover fixed facility costs still works out to 273 years. There is another viewpoint, which

holds that there will be an induced demand for maglev trains due to developments in

computer technology and communication systems. Induced demand will bring in new

ridership of 200 to 400% of the predicted levels by 2020, while diversion from other

modes to maglev will be limited. In this case the project could recover its costs within 30

years. There is also a case for going ahead with maglev research even if it appears to be

uneconomical at the present juncture. Better materials and technology will greatly reduce

the prohibitive initial costs in the near future. The spin-offs from maglev research into the

fields of medicine, linear drives, automobile industry etc. cannot be enumerated. Also,

maglev has a certain romantic appeal and showcasing maglev technology will be an issue

of national pride.


5.10 If maglev between Chennai and Bangalore: -

A maglev train running between Chennai and Bangalore would complete the

journey in not more than 90 minutes. The following are to be considered for pricing. At

present, passenger rail travel is highly subsidized due to cross-subsidization from

freight rates. Therefore it would be extremely difficult to compete with the Railways in

passenger transport. An indicator of this is the ratio of (net earning per passenger km)

to (net earning per freight tonne km). This ratio, (ideally unity) is about 1.15 in China,

but a miserable 0.3 in India. (Source: World Bank). However there are indications that

this policy is on the way out. This may see a hike in passenger fare of more than 200%

over the next five years. At present, passenger fares are:

Mode of transport Fare

Express train Rs. 110/-

Sleeper train Rs. 175/-

Bus (Ordinary) Rs. 150/-

Bus (Luxury) Rs. 220/-

Shatabdi express Rs. 560/-

Transit time by train/bus is around six hours at an average speed of 60 kmph. (120

kmph. on the Shatabdi). Maglev would offer a very fast and smooth ride when

compared to these, also saving 4 hours of time. When the Golden Quadrilateral

project is complete, road travel will be an option competing with railways for both

passenger and freight movement. A trip by automobile would cost 360km. / 15kmpl.


* Rs.35/ltr = Rs. 840. In the future of satellite towns, daily commuting between cities

may be a necessity. Maglev would greatly reduce transit times. With further

development, air traffic is bound to increase, leading to increased pressure on

airports. Current air price is Rs. 2000/-. There are 3 express trains and 2 sleeper

trains, and around 20 buses each way daily.There are 8 daily flights, each way, of

capacity 150 passengers, flying, say, 60% full then, on the basis of these data we can

easily calculate that how maglev will help us as:

Means Capacity

No. of travellers

(assuming trains,

buses running 80%

full)

Express train 13 x 108 = 1404 24,59,808

Sleeper train 13 x 72 = 936 10,93,248

Bus 40 4,67,200

Air 150 5,25,600

Total 45,45,856

Clearly, about 78% of the total commuters travel by express/ sleeper rail. Hence the

maglev alternative would have to compete with rail fares. Assuming an increase of 150%

in rail fares (very optimistic), the fare would rise to about Rs. 440/- in the next 10 years

(project timeframe). The maglev trip could be priced at Rs. 500/-. Assuming that only

half these travelers opt for the maglev, the revenue generated would be Rs. 500 x

22,72,928 = Rs. 113.7 crores.

CHAPTER 6

PROJECT MODEL

project model (46)

CHAPTER 6: OUR PROJECT

6.1 Block diagrams:

6.1.1 Block diagram for propulsion :-

Propulsion can be easily understood by the block diagram. Stepper motor logic is

the heart of the system for propulsion system.

fig 6.1.1 Block diagram of propulsion

We are using half step logic for our project purpose. This logic can be explained as. For

the logic given below:

H = HIGH = +1V

L = LOW = 0V

Half stepping:-

Half step logic is a combination of two logics i.e. wave and full step logic. this

logic can be understood simply as:

project model (47)

STEP L1 L2 L3 L4

1 H L L L

2 H H L L

3 L H L L

4 L H H L

5 L L H L

6 L L H H

7 L L L H

8 H L L H

The reason for using this logic is very simple because the half-step sequence has the

most torque and is the most stable at higher speeds. It also has the highest resolution of

the main stepping methods.

fig 6.1.2 Block diagram of levitation

project model (48)

6.1.2 Block diagram for levitation:-

Levitation can be understood easily understood with the help of block diagram. The

goal of this system is to make the process output equal to the reference input at all times,

even if the process is perturbed by outside forces. We will describe each of the

components of this system and relate them to a familiar control system: the speed control

operation of a car by a driver.

The input signal is called a Reference Input or command. In our example, this

would be the speed limit sign stating that the limit is 55MPH.

The Feedback signal is a representation of the process output of the system, and is

used for comparison to the reference. Most often the feedback signal goes through a

converter or amplifier so its signal can be directly compared to the reference input signal.

The Comparator simply subtracts the feedback signal from the input signal in

order to create an Error or difference signal. A positive error signal will cause the process

output to increase. Similarly, a negative error signal will cause the process output to

decrease.

The Error Amplifier converts the error signal to something the process can use.

The type and gain of this amplifier directly affects how quickly and how well the output

of the process will follow the reference input.

The Process or load takes the output from the amplifier and converts it to the

Process Output which is the parameter being monitored and controlled. Even if the output

from the error amplifier does not change, the process can vary over time which will affect

the output of the system. This is where the beauty of a feedback control system shines.

project model (49)

Since the feedback signal continually monitors the process output, and is continually

being compared to the reference input, the system can continually adjust for variations in

the process.

fig 6.2.1 Basic circuit diagram for levitation

project model (50)

6.2 Circuit diagrams :-

6.2.1 Basic circuit diagram for levitation.

The linear Hall Effect device, HE3503, is fed from a +5V source. Now, when there is no

magnetic field near the Hall Effect device, its output voltage is about 2.5V. When a North

Pole approaches the marked surface of the device, the voltage drops to about 1V at 1000

Gauss. When a South pole approaches it, the voltage rises to about 4V at 1000 Gauss.

What we want to do is make the output at V1 equal to zero when there is no magnetic

field, +9V at maximum Gauss North pole, and -9V at maximum Gauss South pole. To do

this, we will use LM324 op-amp ICs that contain four op-amps. First, we take the output

of the hall effect device directly into an op-amp, OA1, that acts like a follower (its output

is the same as the input, but with lower impedance). It then feeds a 1k resistor into

another op-amp, OA3 that acts like an amplifier with an adjustable gain between 0 and 10

times. In order to get rid of the 2.5V offset when no magnetic field is present, we have

the ZERO_1 pot that feeds from the same +5V supply, and it is inverted by OA2. to set

this up, we start with no magnetic field near the hall effect device. Set the GAIN_1 fully

clockwise for maximum gain, and look at the voltage test point V1. Adjust ZERO_1 until

the voltage at V1 is zero. Now, place the Hall Effect device onto the electromagnet.

When full power is applied to the electromagnet, adjust GAIN_1 to +9V out at V1. Next,

we build another circuit identical to this one, and label the pots ZERO_2 and GAIN_2.

Set them up the same way. Its output is at test point V2. The way we attach these Hall

Effect devices to the steel core of the electromagnet will have an affect on how the

feedback will work. We want the top surfaces of the Hall Effect devices on the face of the

steel core, for both the one on the top and the one on the bottom of the electromagnet

core. This is diagrammed below when we talk about construction. The reason for this is

to obtain two opposite polarity signals. The gain adjustment pots will be tweaked to make

sure they cancel each other out when no magnet is near either one of them. This way, V1

will be the negative of V2, and their sum, V3, will be zero volts. When a magnet

project model (51)

approaches one of the ends of the electromagnet, causing an imbalance in their output

signals, the sum of V1 and V2 will no longer cancel and V3 will no longer be zero but

could be positive or negative, depending on the polarity of the magnet. The output V3 is

the position feedback signal. We now need a position reference signal. This comes from

the pot labelled POSITION. The next op-amp compares V3 to the POSITION pot voltage

level, and creates an error signal at test point V4. If V3 is closer to zero than the

POSITION voltage level (please note that the POSITION voltage level is a negative

voltage) the output V4 will integrate to about +10V. If the absolute value of V3 is greater

than the POSITION voltage level, then the output V4 will integrate to 0V and stay there.

The diodes around that op amp prevent V4 from going negative.

fig 6.2.2 Power circuit for levitation

project model (52)

6.2.2 Power circuit for levitation :-

Now on to the error amplifier, process and the process output sections of the control. This

circuitry takes the error signal, V4 (from the op-amp in the previous circuit above), and

uses it to control the current in the electromagnet, directly controlling the strength of the

electromagnet's magnetic field. The 555 timer on the left is a free-running oscillator that

operates around 1 kHz at V6. Its duty cycle is about 1%. The 555 timer on the right takes

that signal and creates a pulse-width-modulated signal, using the oscillator as the carrier

frequency, and with a duty cycle proportional to the voltage seen at V5. Please note that

the DUTY-CYCLE LIMIT pot sets the maximum duty cycle allowed out at V7. When

V5 gets close to the +V of 12 volts, the PWM becomes erratic, so this pot prevents this

from happening. This also limits the maximum current that the electromagnet will be

allowed to carry by limiting the voltage to the electromagnet. V7 feeds the gate to an

IGBT (insulated gate bipolar transistor) causing it to turn on when V7 is high, and turn

off when V7 is zero. The pulse-width-modulation simply allows the IGBT to be on for a

certain portion of its 1 kHz cycle, and off for the rest. The average of its on time to its

cycle time will be proportional to the average current in the electromagnet. This allows

for quick response. The only thing the IGBT can do is turn on or off, it can not reverse

the current through the electromagnet if the permanent magnet gets too close and needs to

be pushed away. We are counting on gravity to pull the permanent away from

electromagnet when the IGBT is off. The electromagnet is powered by its own 24V

source. It will be handling a fair amount of current. There is a fast recovery diode around

the electromagnet to allow the current that was flowing through it to "freewheel" around.

If it weren't there, the electromagnet would create a very high voltage whenever the

IGBT switched off, damaging the IGBT. The diode around the IGBT isn't needed for this

circuit, but is part of IGBT package.

project model (53)

fig 6.2.3 Circuit diagram for propulsion

project model (54)

6.2.3 Circuit diagram for propulsion:-

Stepper motor drive circuit generates the required logic to run the stepper motor.

The above circuit generates full step logic with the help of three T flip-flops. T flip flop

output status changes with the rising edge of clock pulse. Q and Q’ of T1 flip-flop is

connected to clock terminal of T2 and T3. Let the output of T2 and T3 be A, C and B, D

respectively. When T1 receives first clock pulse from the controller, Q gets high and Q’

gets low. Q terminal of T1 is connected to clock of T2, as a result T2 clock terminal

receives clock pulse when Q gets high and the output of T2, A gets high, C gets low, at

T3 output terminal B is low And D is high. For the second clock pulse output of T1 Q

gets low and Q’ gets high. Q’ of T1 is connected to clock of T3 , output status of T3

changes from B (low) to B (high) and D (high) to D (low). This sequence of changing

the output status of T2 and T3 continues. T2 changes its output status in every odd clock

pulse and T3 changes its output status in every even clock pulse. In this way the required

logic is generated until T1 receives clock pulses. To rotate the stepper motor in reverse

direction, reverse logic should be implemented. To implement reverse logic,

1. Coil A of stepper motor is connected to the logic of D.

2. Coil B of stepper motor is connected to the logic of C.

3. Coil C of stepper motor is connected to the logic of B.

4. Coil D of stepper motor is connected to the logic of A.

To reverse the logic 2 sets of AND gate is used. Input A of first set of 4 AND gates are

connected to one common terminal named “clockwise”, Rest 4 input terminals B1, B2,

B3, B4, are connected to terminals (A, B, C, D) respectively, coming out from T flip-flop

logic circuit. When the terminal “clockwise” is low, the output status of all 4 AND gate is

low irrespective of input status of A, B, C, D. When “clockwise” terminal is high the

project model (55)

logic is allowed to go to motor. Same control applies for “counter clockwise” terminal.

The 2 sets of 4 AND gates used to guide the motion of motor has ability to deliver

maximum 20 miliampare, but motor require 180 miliampares at full load. To supply the

required current to motor, array of Darlington transistor is used. Clockwise and Counter

clockwise logic are connected together with the help of OR gate. To have a visual

indication of the status of stepper motor logic group of 4 LED’s are implemented and one

LED for clock. These LED’s help at the time of debugging the circuit.

fig 6.3 (a) Regulated power supply

fig 6.3 (b) Block diagram of regulated power supply system6.3 Power supply:-

There are many types of power supply. Most are designed to convert high voltage

AC mains electricity to a suitable low voltage supply for electronics circuits and other

project model (56)

devices. A power supply can by broken down into a series of blocks, each of which

performs a particular function.

Transformer - steps down high voltage AC mains to low voltage AC.

Rectifier - converts AC to DC, but the DC output is varying.

Smoothing - smoothes the DC from varying greatly to a small ripple.

Regulator - eliminates ripple by setting DC output to a fixed voltage.

The regulated DC output is very smooth with no ripple. It is suitable for all electronic

circuits. Transformers convert AC electricity from one voltage to another with little loss

of power. Transformers work only with AC and this is one of the reasons why mains

electricity is AC.

Step-up transformers increase voltage, step-down transformers reduce voltage. Most

power supplies use a step-down transformer to reduce the dangerously high mains

voltage (230V in UK) to a safer low voltage.

The input coil is called the primary and the output coil is called the secondary. There is

no electrical connection between the two coils, instead they are linked by an alternating

magnetic field created in the soft-iron core of the transformer. The two lines in the middle

of the circuit symbol represent the core.

http://www.kpsec.freeuk.com/powersup.htm#regulator

http://www.kpsec.freeuk.com/powersup.htm#smoothing

http://www.kpsec.freeuk.com/powersup.htm#rectifier

http://www.kpsec.freeuk.com/powersup.htm#transformer

Transformers waste very little power so the power out is (almost) equal to the power in.

Note that as voltage is stepped down current is stepped up.

project model (57)

The ratio of the number of turns on each coil, called the turn’s ratio, determines the ratio

of the voltages. A step-down transformer has a large number of turns on its primary

(input) coil which is connected to the high voltage mains supply, and a small number of

turns on its secondary (output) coil to give a low output voltage.

A bridge rectifier can be made using four individual diodes, but it is also available in

special packages containing the four diodes required. It is called a full-wave rectifier

because it uses the entire AC wave (both positive and negative sections). 1.4V is used up

in the bridge rectifier because each diode uses 0.7V when conducting and there are

always two diodes conducting, as shown in the diagram below. Bridge rectifiers are rated

by the maximum current they can pass and the maximum reverse voltage they can

withstand (this must be at least three times the supply RMS voltage so the rectifier can

withstand the peak voltages). Please see the Diodes page for more details, including

pictures of bridge rectifiers.

Smoothing is performed by a large value electrolytic capacitor connected across the DC

supply to act as a reservoir, supplying current to the output when the varying DC voltage

from the rectifier is falling. The diagram shows the unsmoothed varying DC (dotted line)

and the smoothed DC (solid line). The capacitor charges quickly near the peak of the

varying DC, and then discharges as it supplies current to the output.

Smoothing is not perfect due to the capacitor voltage falling a little as it discharges,

giving a small ripple voltage. For many circuits a ripple which is 10% of the supply

voltage is satisfactory and the equation below gives the required value for the smoothing

capacitor. A larger capacitor will give fewer ripples. The capacitor value must be doubled

when smoothing half-wave DC.

C =smoothing capacitance in farads(F)

Io = output current from the supply in amps (A)

http://www.kpsec.freeuk.com/components/capac.htm#polarised

http://www.kpsec.freeuk.com/components/diode.htm#bridge

http://www.kpsec.freeuk.com/acdc.htm#rms

Vs = supply voltage in volts (V), this is the peak value of the unsmoothed DC

f = frequency of the AC supply in hertz (Hz), 50Hz

project model (58)

Voltage regulator ICs are available with fixed (typically 5, 12 and 15V) or variable

output voltages. They are also rated by the maximum current they can pass. Negative

voltage regulators are available, mainly for use in dual supplies. Most regulators include

some automatic protection from excessive current ('overload protection') and overheating

('thermal protection').

fig 6.4.1 PCB for levitation

project model (59)

fig 6.4.2 PCB for propulsion

6.4 PCB design:-

6.4.1 PCB for levitation

6.4.2 PCB for propulsion

Printed circuit boards (PCB's) are laminates. This means that they are made from two or

more sheets of material stuck together; often copper and fibreglass. Unwanted areas of

the copper are etched away to form conductive lands or tracks which replace the wires

carrying the electric currents in other forms of construction. Tracks on one side can be

joined to tracks on the other by means of wire links. Plated through holes are available

which do the same thing but these make the PCB more expensive. Components are

stuffed into the board by hand or by pick and place machines.

Exposure:-

The design layout of the PCB is done on the computer using CAD; the program is

EXPRESS PCB. The layout is printed out on a transparent A4 size sheet called acetate,

project model (60)

which is especially used for the purpose. This is done in the same way as printing out a

word document. Care must be taken to ensure the circuit layout will be to scale and won't

be too big to fit on the sheet. The layer to be printed out must be defined and pad holes

must be set to 'Avoid' so as black dots and not rings are printed to indicate holes to be

drilled. The base material is FR4 epoxy all woven glass laminate, thickness 1.6mm with

copper foil cladding 1 oz per sq. ft. The surface resistance is 100,000 Mega ohms. Photo-

resist is positive working sensitive to ultra violet light with a developed image of

blue/green tint. The copper-clad laminate board consists of a layer of copper, covered

over by a layer of green resin called photo-resist. The protective black plastic tape, that

protects the copper laminate from scratches, is removed to reveal green positive photo-

resist covering the copper. The printout mask of the image (on acetate) is put over the

photo-resist face down, so a mirror image of the circuit layout can be seen over the

photo-resist side of the laminated board. On single sided boards this is important because

the PCB is designed from looking down from the component side, but the tracks are on

the opposite side of the laminated board on the copper side, therefore a mirror image of

the PCB layout must be seen. With single a sided board, the acetate is placed over the

photo-resist side. In each case the laminate and acetate are enclosed under ultraviolet

light and agitated for 2 to 8 minutes.

Developing:-

A solution of Liquid photo-resist Developer concentrate is mixed in a beaker with 1

part developer to 9 parts water, total 500mls and poured into a basin. A beeper will sound

when the 2 minutes are up, the board is taken out of the UV enclosure, and (the acetate is

not required any more). The green photo-resist that was exposed will appear a lighter

colour and the darker imprint of the PCB can be seen when examined closely. The board

is put into the solution and the liquid is flowed over and back on the board. The lighter

photo-resist will flow away showing copper and the PCB layout will be revealed. It will

be necessary to wash the board under tap water and clean with tissue paper to ensure no

project model (61)

traces of photo-resist remain on the copper, otherwise etching would be difficult. A PCB

marker pen can be used to correct any errors such as breaks in the track at this stage.

Etching:-

The etching tank is about half the size of the household water tank in the attic. The tank

consists of two compartments. One compartment is 2/3 the size of the other compartment.

The larger compartment consisted of a thermostatically controlled heater element.

Covering the heater is a protective grill mesh. This grill mesh filters the waste copper

away from the heater element .The tank would be filled to the level of the filter with

Ferric Chloride Hexahydrate solution, about 5 litres. The solution is made up of etchent

granules dissolved in water. An electric motor spins a shaft enclosed in a tubular barrel

18 inches long containing holes perforated on the circumference from top to bottom. The

motor and tube are vertical from the top of the tank so as when switched on, the motor

spins the tube and stirs the solution. The effect is to suction of the solution into the barrel

and to spray the board being etched. The solution is heated to 50 degree Celsius before

use; a light on the control panel will extinguish when the temperature is reached. The

board held in a clamp the copper side facing the centre of the tank so as to gets the full

force of the spray. On the control panel the timer is set to between 3 to 10 minutes,

depending on the quality of solution and size of the board. A 'start etch button' is

depressed and the display will count down, a beeper will sound when the timer has

reached zero, all exposed copper should be disolved away from the board. The smaller

compartment is plumbed into the water main and is continually flushed, and is used for

washing the board after etching is complete. For double-sided boards, the process is

repeated on the opposite side of the board.

Stripping (optional) :-

After etching the positive resist 9 (photo-resist) maybe left on the copper to act as

project model (62)

protection. Solder is readily achieved through the resist. This green photo-resist can be

removed using a tube of photo resist stripper, (like shoe polish) and the PCB washed

clean under tap water and dried using tissue paper.

Drilling:-

After cutting the PCB to size around the perimeter using the guillotine, drilling using a

0.9-mm drill can now be performed in the workshop. The board is now ready to stuff

with components.

6.5 Component list :

SNO PART NO. PART DESCRIPTION QTY. PRICE

1. CD4081 Quad 2 input AND gate 5 20.00

2. CD4027 Dual JK flip flop 4 36.00

3. ULN2803 Octal Darlington transistor array 2 80.00

4. LM 7909 5V fixed voltage regulator 1 15.00

5. LM 7805 5V fixed voltage regulator 1 15.00

6. NE 555 Timer IC 1 8.00

7. 1000uf/25v Electrolytic capacitor 1 10.0

10k ¼ watt resistance 10 2.5

1k ¼ watt resistance 4 1.0

4.7 ¼ watt resistance 4 1.0

820R ¼ watt resistance 8 3.0

270R ¼ watt resistance 18 2.5

8. 1N514 LED 2V 13 13.0

9. T1 Transformer 0-12V /1A 1 50.0

10 SOLINOID

COIL

Electromagnet 1 350.0

11 MAGNET Rare earth metal magnets 1 100.0

12 LM 324 OP AMP 3 30.0

13 HE 3503 Hall effect sensor 2 1280.0

14 LM 7809 Power I for propulsion 1 15

15 Power circuit for Electro Magnet 1 250

16 Aluminum frame in physical mode 1 300

27 Hardware 5000

6.6 Problem arrived in project with solutios:

In between centre of coil solid iron rod is placed to attract object. Due to

oscillating voltage to the coil, coil will generate magnetic field which is going

continuously ‘ON’ and ‘OFF’. The iron rod which is placed is solid so due to

varying magnetic field eddy current generated in the solid iron core. Due to

eddy current enormous amount of heat is generated and due to which hall effect

sensor, placed at the bottom of rod get defected.

The problem is removed by placing the heat insulators between hall effect

sensors and the iron core.

By using full stepper logic and wave step logic we were not able to

propel the vehicle on the track. The reason was that this logics were not able

to generate that much amount of torque which will be sufficient to move the

vehicle.

project model (64)

The solution of this problem is in the combination of these both logic. We

then use the ‘half step logic’ which is the combination of both the logics. Thus

due to this much, almost double torque get generated and vehicle moves.

When both the model gets operated together simultaneously then the

magnetic fields for the levitation always disturb the magnetic field of propulsion

or vice-versa.

This problem can only be solved by selecting the right material for which

retentivity is so low so that when we ‘OFF’ the current in the track it

immediately changes its polarity generated by the current previously flown in

the track. Another solution of this problem is to increase the distance between

track so that the magnetic lines of forces of both the magnets or magnetic fields

do not get disturbed by each other.

CHAPTER 7

APPLICATION

Application (65)

CHAPTER 7: APPLICATION

fig 7.1 (a) Overview

7.1 Overvie w :-

This chapter summarizes the key features of the M3 design. M3 was designed with

the following objectives .

Decrease travel time by at least a factor of 2:

Allow speeds up to 45 m/s (101 mph), acceleration and braking up to 2 m/s2,

short average waiting time and reduced dwell time.

Application (66)

Decrease operating cost by at least a factor of 2:

Use less energy and reduce labor and life cycle costs.

Reduce guideway cost by at least a factor of 2:

Reduce guideway weight by reducing vehicle weight and matching the guideway to the vehicle.

Reduce environmental impact:

Reduce noise, guideway size and energy consumption.

Create an improved ElectroMagnetic Suspension (EMS):

Use permanent magnets with a 20 mm magnetic gap (15 mm physical gap) and make each magnet contribute to lift, guidance and Linear Synchronous Motor (LSM) propulsion.

Provide excellent ride quality:

Pay careful attention to guideway design and take advantage of the distributed and non-contacting nature of maglev forces.

Create a very safe transportation system: Use a dedicated guideway, vehicles that cannot derail, linear motor propulsion

that does not depend on friction and totally automated operation.

Application (67)

fig 7.1 (b) Cross section of the guideway beam and vehicle

Application (68)

Following are the key performance specifications that were the basis of the design:

Speeds up to 45 m/s (162 km/h, 101 mph)

Acceleration and braking up to 2 m/s2 (4.4 mph/s)

Headways as short as 4 seconds when operated in platoons

Capacity up to 12,000 passengers per hour per direction (pphpd)

Horizontal turn radii of 18.3 m (60’) and vertical radius of 300 m (984’)

Target cost of $20 million per mile including vehicles

Minimum environmental impact with reduced noise and energy consumption

Figure 7.1 (b) shows a cross-section of the guideway beam and the vehicle. The

permanent magnets on the vehicle provide lift, guidance and act as the field for Linear

Synchronous Motor (LSM) propulsion. Control coils wound around the magnets

stabilize the suspension and adjust the nominal magnetic gap to the value

that minimizes power requirements for the control. Windings in the guideway are

excited by inverters located along the guideway and provide controllable thrust for

acceleration, cruise and braking. The secondary suspension on the vehicle provides

improved ride quality but can be omitted for lower speed operation. This is only a

preliminary design and will be refined in the next phase of development. The design of

Application (69)

the M3 system has focused on the components that contribute most to performance and

cost with a particular focus on subsystems that have unique features:

Permanent magnet EMS suspension, LSM design and manufacture, guideway beams,

vehicle suspension and control systems. In order to create confidence in the basic

design a demonstration prototype has been constructed and tests to date are very

encouraging. Future plans call for extending the test track and ultimately building a

high-speed test loop as a prelude to installing a commercial system.

7.2 Electromagnetic suspension and guidance :-

A key design objective was to create a suspension that: is suitable for low to moderate

speeds with frequent station stops, allows vehicles to make small radius turns in both

the horizontal and vertical directions, and is suitable for use with small vehicles.

Members of the MagneMotion maglev team have had considerable experience with both

Electromagnetic Suspension (EMS) and Electrodynamic Suspension (EDS). A careful

review of the merits of each led us to pick the EMS design for the following reasons:

No need for an auxiliary suspension at low speeds

No need to provide high propulsive force at low speeds to overcome magnetic

drag

No need to shield the passengers from unacceptably high magnetic fields

Reduced cost for a complete system.

Following is a discussion of the M3 features that contribute to decreasing cost and

increasing performance.

Application (70)

7.2.1 Permanent ma g net EM S :

A key feature of the M3 suspension is that every permanent magnet on the vehicle

contributes to suspension, guidance and propulsion. This is analogous to the way every

railroad wheel provides suspension and guidance and can play a key role in propulsion

and braking. Without this 3-way combination there is added cost and complexity. For

example, Transrapid uses one set of electromagnets to provide both lift and a field for

an LSM but requires separate steel rails on the guideway and a separate set of feedback

controlled electromagnets on the vehicle to provide guidance. The Japanese low speed

HSST and Korean Maglev designs provide lift and guidance with a single

electromagnetic structure but require a separate aluminum reaction rail on the guideway

and Linear Induction Motor (LIM) primary on the vehicle to provide propulsion. For

M3 the integration of these three functions allows the vehicle magnet arrays to be

mounted on pods that can rotate like wheel bogeys to allow sharp turns in both the

horizontal and vertical directions. Figure 7.1(b) shows a pod with permanent magnets

attracted upward to a laminated steel suspension rail. Control coils around the magnets

are used for stabilization and windings integrated into the suspension rails provide

propulsion. Half-length magnets at the ends of the pod equalize magnetic flux and

mitigate cogging. This drawing shows propulsion windings wound on teeth on a

guideway rail and suspension control coils wound around permanent magnets on a

vehicle pod. Coils wound around the magnets are excited from a controller that uses

gap and acceleration sensors to control current in these coils to stabilize the magnetic

gap at that value which provides a match between vehicle weight and permanent magnet

force. Ideally it would take negligible power to stabilize the suspension and in practice

the power requirement is dramatically less than it would be if the entire suspension force

were provided by electromagnets alone. When the vehicle is stationary the required

control power will be only a few watts and at operational speeds it is expected to be on

Application (71)

the order of 100 W per tonne of vehicle mass. For comparison, Transrapid uses

electromagnets for suspension and they require 1,000 W per tonne of vehicle mass for a

suspension with a magnetic gap of only 10 mm, and require additional power for

guidance. The use of permanent magnets allows the use of a magnetic gap of 20 mm

with a corresponding reduction in guideway tolerance requirements. The vehicle mass is

estimated to be 7±1.5 tonnes according to the number of passengers onboard. The

suspension controller will adjust the magnetic gap to minimize control power and thus

the gap will vary ±3 mm; a higher load will lead to a smaller gap and vice versa.

7.2.2 Horizontal and vertical turns:-

Creating a maglev system that can negotiate tight turns has been a challenge to all

maglev designers. In a cost-effective design the magnetic force must be distributed over

a large area but for making tight turns the suspension magnets must be articulated so

that they follow the turn. The M3 mechanism for doing this is shown in Fig 2.3-5. This

preliminary design is for a 24-passenger vehicle that can negotiate horizontal turn radii

of 18.3 m (60’) and vertical turn radii of 300 m (984’). Improved designs are being

studied.

7.3 Linear Motor Propulsion :-

Maglev developers have universally adopted the linear electric motor as the

propulsion system of choice for maglev. There are two types of linear motor that are

currently being used for commercial designs:

Linear Induction Motor (LIM)

Linear Synchronous Motor (LSM).

Application (72)

The only practical version of the LIM is one that has an onboard motor primary. This

design has some advantages.

A power inverter is required for each vehicle motor, but the total cost of inverters

for a complete system is reduced

The guideway portion of the LIM consists of an aluminum sheet, sometimes on

steel backing, and this is less expensive than an LSM stator.

But the LIM has major disadvantages..

The vehicle weight is increased by at least 20% because of the onboard

propulsion equipment.

It is very costly in weight and efficiency to operate with a magnetic gap more

than about 10 mm and thus guideway tolerances are more critical.

It is necessary to use sliding contacts to transfer all of the propulsion power to

the vehicle or, at much greater cost, to use inductive power transfer.

The motor efficiency is reduced, both because the motor is less efficient and

because the vehicle is heavier and requires more propulsive thrust.

The only practical version of an LSM is one that has the propulsion winding on the

guideway, the so called “long stator” design. This has a number of important

advantages.

The motor can use the same magnets as the suspension and thereby reduce

vehicle cost and weight and increase efficiency.

The magnetic gap can be larger.

Application (73)

The vehicles are lighter so less propulsive power is required.

No need to transmit propulsive power to vehicle.

The propulsion and control equipment is all on the guideway so communication

is more robust, control is simplified and regenerative braking is easier to achieve.

The disadvantages of an LSM include:

Higher cost for guideway-mounted LSM motor windings and wayside power

inverters.

Precise position sensing is required.

Virtually all high-speed maglev designs use an LSM for propulsion. Early versions of

transrapid used the LIM but starting with TR05 in 1975 they switched to the LSM. The

Japanese high-speed maglev developers have always used an LSM. The Japanese HSST

and Korean designs use a LIM but they have limited speed capability. A superficial

analysis of cost might suggest that LIM propulsion is less expensive but when all of the

costs associated with the negative aspects are considered it is likely to be more

expensive for a complete system. The dramatic reduction in the onboard power

requirements is also a strong incentive for using an LSM. For M3 with a need for light

vehicles and a 20 mm gap the LIM is not a viable alternative. Details of the M3 LSM

design are discussed in this section.

7.4 Guideway:-

The focus of the M3 design effort was to keep the guideway beams as small and

light as possible without jeopardizing ride quality. The resulting design is based on

deflection considerations, and the strength of the structures is far greater than is

Application (74)

necessary so there is no compromise with safety. The relatively small size of the

guideway is evident in the artist’s rendition on the cover of this report. Note that the

peer spacing is relatively large and the beam cross-section relatively small when

compared with virtually all other elevated transit systems. For new installation it is

believed that most urban maglev systems will use elevated guideways to avoid the

right-of-way access and safety problems of at-grade guideways or the cost of tunnels.

Maglev vehicles make no wheel or engine noise and very little wind noise at speeds

suitable for urban transportation. Many of the objections to elevated guideways are

ameliorated by the M3 design. In some cases Urban Maglev will operate at-grade or in

tunnels and in these cases the eams can have a smaller height with more frequent

supports, but the design principles are the same. For example, a reduced height beam

could be mounted directly on concrete ties to replace rails in a rapid transit retrofit.

Guideway cost is a dominant item so considerable effort has been made to reduce cost by

reducing size and weight.

fig 7.5 vehicles

Application (75)

7.5 Vehicles:

Magnemotion is working with vehicle manufactures to estimate the cost and the

weight of a vehicle. Fig 7.5 shows an intial vehicle design with articulated magnet pots

for suspension on guideway with LSM propulsion . An improved design will be

developed in future phase of this project. The lack of any onboard propulsion equipment

simplifies the interior design and makes it possible to put HVAC and other equipment in

the nose and tails with streamlining prevents use for passenger. This reduce drags and

lowers the centre of gravity, both important for this application. This primary suspension

is provided by the magnets but there may be a secondary suspension that may have two

components; the magnet pots have pivots with dampers so as to allow tight turning radii

in both horizontal and vertical direction, and pneumatic springs allowed improved ride

quality, including tilting. Ride quality is often measured by determining the frequency

profile of the vertical acceleration and comparing this with desired limits based on

subjective experiment with passengers. The preliminary estimates indicate that a 24-

passenger vehicle will weigh about 5.5 tonnes empty and cost about 330 k$. For

comparison, a typical articulated light rail vehicle weights 40 tonnes empty and costs

about 2,500 k$. The light rail vehicle has a crush load capacity of about 200 passengers,

but in typical operation it only takes 3 24-passenger maglev vehicles to provide the same

capacity as one light rail vehicle because of the higher average speed. Thus maglev

vehicle cost less than half as much as for light rail and maintenance cost should also be

much less. The improved comfort for passengers is a bonus.

7.5.1 Issues involved in choosing vehicle size:-

European and Japanese maglev developers have always viewed maglev as a

Application (76)

modern form of train travel with the potential for higher speeds, lower maintenance cost,

etc. The German Transrapid and the Japanese high-speed designs all use multicar trains

with each train carrying several hundred passengers and train spacing of several

minutes. In contrast, U.S. maglev developers have always thought of maglev as form of

bus or airplane with a preference for smaller vehicles operating more frequently. All 4

designs that resulted from the U.S. 1992 National Maglev Initiative recommended the

use of individual vehicles with capacities less than a 100 passengers.

Advantages of using large vehicle are:

Lower labor cost when operated manually.

Higher capacity is possible.

Lower aerodynamic drag per passenger

Vehicles are less expensive per passenger.

Advantages of using smaller vehicles:

High vehicle frequency

Reduced propulsion power per vehicle

Platoons are move versatile than trains

Easier to reuse regenerated energy.

For automated operation at speeds up to 45 m/s (101 mph) the advantages of using

smaller vehicles are substantial. The use of a linear motor that does not depend on

friction for braking makes it possible to operate with very short headway and hence the

capacity advantage of a train is eliminated. At these speeds and for urban use the

aerodynamic drag is not the major power consumer. The vehicle cost advantage

disappears if the vehicles operate with higher top speeds so that fewer vehicles are

Application (77)

required. If the operating speed were to increase by a factor of 2 to 3 there would be

merit in some increase in size but there does not appear to be any operational advantage

of using a long train for maglev.

7.5.2 Vehicle design for system:-

For urban use at speeds up to 45 m/s. the M3 design is based on vehicle that can

carry 24 passengers seated and another 12 standing when operated with platoons and 4-

second headway within a platoon this size vehicle can transport up to 12,000. for lower

speeds and capacities a smaller vehicle can be used. Our baseline design for smaller

vehicle is one that carries half as many people as the high speed version.

7.6 Cost estimate :-

The section itemizes system components and estimates the cost per mile for the

M3 Urban system .costs are compiled from information supplied by component designers

and manufacturers and have been confirmed by a second source where possible. In a few

instances there is not enough information to make an accurate estimate, but all of the

primary costs have been determined after consultation with appropriate manufacturers

and vendors.Magnemotion will continue to refine the cost estimate as the design

involves. the cost estimate for all guideway related items are computed on a per-unit-

beam-length basis. The baseline design calls for double-span beams that are 72 meters

long.

Each 72-meter length of guideway contains the following:-

2pipes

2.72-meter long beams

Application (78)

8.36-meter long LSM stators

1 inverter station containing 8 inverters and associated controllers

1 hub controller and communication module

4 power cables for distributing DC power, 2 in each beam.

The DC powers is provided be a rectifier station located every 8kn(4.97miles) and each

station contains a power transformer and rectifiers that provide separate +750 and -750V

DC power with a total power rating of 1.5 MW.

The rectifier stations may include a source of emergency power but this cost has not been

included a rough estimate is $ 50,000 added cost for every rectifier station for a 50 KW

generator. Power station rating and spacing is consistent with operating 4 vehicles per

mile of dual guide way ,soi this is user as the nominal vehicle required. For different

application the number of vehicles per mile could vary substantially. If smaller and lower

speed vehicles are use the cost of the vehicles and power system will be somewhat lower.

The order of the costing section follows highest to lowest cost components.

Power distributions and control

Guideway

LSM stator

Vehicles.

In 2002 dollars, of each major component, it is assumed that the installation is atleast 10

miles, long with the expectations that costs will be somewhat higher for shorter

installations. The extended price includes the contingency factors for component parts,

but does not include civil works, shipping or land acquisition costs. Component

Application (79)

contingencies account for uncertainties in our cost estimates and are based on discussion

we have had with various vendors regarding the relative risk associated with the

estimates. Even with the 25% to 50% contingencies added, M3costs are well below those

of competing transit systems.

CONCRETE HYBRID STEEL

POWER AND CONTROL 9.589 9.589 9.589

GUIDEWAY 6.376 8.625 12.691

LSM STATOR 4.054 4.054 4.054

TOTAL EXCLUDING VEHICLES 19.779 22.260 26.351

4 VEHICLES 1.322 1.322 1.322

TOTAL WITH 4-24 PASSENGER / MILE

21.101 23.582 27.673

TOTAL COST IN M$/mile FOR THREE GUIDEWAY ALTRENATES AND BASELINE VEHICLES

Thus the cost objective of $20M per mile is clearly achievable if we can improve the

design further and reduce the need for large contingencies.

CHAPTER 8

SUGGESTIONS FOR FURTHER ENHANCEMENT IN APPLICATION

Suggestions for further enhancement in application (80)

CHAPTER 8: SUGGESTIONS FOR FURTHER ENHANCEMENT IN APPLICATION

Guideway Structure :

Fixed facilities account for about 90% of the total maglev capital costs

(Transrapid). The guideway structure represents 70% of the fixed-facility costs. Any

technological improvements in this area will have a substantial impact on system

economics. At present, there are two different technologies being tested – the repulsive

electrodynamic suspension (EDS) with linear induction motors (LIM) in Japan and the

attractive electromagnetic suspension (EMS) with linear synchronous motors (LSM) in

Germany and China.

Propulsion System :

The propulsion system integrated into the guideway is a major element of capital

cost; breakthroughs in design of such systems could reduce the capital cost. The LIM

requires stricter gap restrictions than the LSM, and is less cost intensive. Many

alternatives or improvements to the LIM and the LSM are being proposed – notably the

pulsed linear motor developed by Sandia laboratories.

Aerodynamic Drag losses:

At high speeds, overcoming aerodynamic drag consumes most of the propulsion

energy. It also tends to nullify some of the advantages of maglev, i.e. low noise and

Suggestions for further enhancement in application (81)

unlimited speed capability. Further improvements in materials would help in increasing

speed. Also to be considered is the option of running maglev trains at low air pressures

in evacuated chambers.

Wheeled Alternatives:

Some experts argue that non-contact propulsion with LSMs on conventional rails

would reduce high guideway construction costs while retaining most of the advantages of

the maglev.

Superconductors and refrigerating systems:

A large part of the power consumption during operation is due to the refrigeration

system and ac losses in the superconducting material. Further improvements would

reduce these costs.

Operational Consideration :

An important operating consideration is whether to use multi-car trains with

limited number of intermediate stops, or frequent single-car trains with multiple

intermediate stops, or single-car shuttle trains servicing individual pairs of stations, etc.

These different operation scenarios will depend on the characteristics of the routes

(length, stations, capacities, etc)

Freight transport:

Freight transport rates of the Indian Railways are extremely high. This may be a

potential market for maglev operation.

CHAPTER 9

REFERENCES

References (82)

CHAPTER 9 REFERENCES

9.1 WEBSITES:-

9th Five Year Plan (Vol-2)Project proposal for a maglev system in Virginia.

(http://www.cs.virginia.edu)

Delhi Metro Rail Corporation Ltd., Project Update.

(http://www.delhimetrorail.com/home/projectUpdate.htm)

Finances of the South Central Railway.

(http://www.scrailway.gov.in/fin_scr.htm).

Bonsor, Kevin. Howstuffworks “How Maglev Trains Will Work”. 22 Nov.

2001. http://www.howstuffworks.com/maglev-train.ht m .

National Maglev Initiative. Final Report on the National Maglev Initiative.

22 Nov. 2001.http://inventors.about.com/library/inventors/blrailroad2.htm#TOP.

Railway Technical Research Institute. Overview of Maglev R&D. 9 Aug. 2000.

22 Nov. 2001. http://www.rtri.or.jp/rd/maglev/html/english/

maglev_introduction_E.html.

http://inventors.about.com/library/inventors/blrailroad2.htm#TOP

http://www.howstuffworks.com/maglev-train.htm

http://www.scrailway.gov.in/fin_scr.htm

http://www.delhimetrorail.com/home/projectUpdate.htm

http://www.cs.virginia.edu/

Richard J. Gran, "Magnetic levitation train," Discovery Channel School, original

content provided by World Book Online. 22 Nov. 2001.

http://www.discoveryschool.com/homeworkhelp/worldbook/atozscience/m/33835

2.html.

References (83)

Canceling Electrodynamic Maglev Suspension. 3 May 1999. 22 Nov. 2001.

http://members.aol.com/marcttpapers/ieee_maglev_part1.pdf

en.wikipedia.org/wiki/Maglev_train

www.rtri.or.jp/rd/ maglev /html/english/ maglev _frame_E.html

www. magnemotion .com

www.magnelift.com/corporate/press-releases/012405/printable.shtml

9.2 GLOSSARY:

AC current – Alternating current. The AC current used in maglev trains is three phase AC current. Each phase is 120 degrees different than the next.

B-field – Magnetic field.

Electrodynamic Suspension (EDS) – Suspension system which uses null flux coils in the guide way. These coils cause the train to rise off the track when there is a strong enough induced E-field in them.

Electromagnet – A group of windings of wires that have a current flowing through them causing a B-field to be set up.

Electromagnetic Suspension (EMS) – Suspension system for a maglev train in which fixed magnets are used to levitate the train using the attractive force of two B-fields.

http://www.magnelift.com/corporate/press-releases/012405/printable.shtml

http://www.magnemotion.com/

http://www.rtri.or.jp/rd/maglev/html/english/maglev_frame_E.html

http://members.aol.com/marcttpapers/ieee_maglev_part1.pdf

http://www.discoveryschool.com/homeworkhelp/worldbook/atozscience/m/33835

Guide way – Name given to the U shaped track system, which maglev trains run on.

Guidance – system that keeps the train in the guide way and from running into part of the guide way.

References (84)

Guidance coil – See Null Flux Guidance-Levitation Coil.

Induced current – current caused by the changing flux of a B-field.

Levitation – To float above something. In this case it is the guide way.

Levitation coil –Null Flux Guidance-Levitation Coil.

Maglev – Magnetically levitated

Null Flux Guidance-Levitation Coil – This coil is a figure 8 coil used for

levitation and guidance of the train. The reason it is in the shape of a figure 8 is

so the B-field produced on the bottom and the B-field produced on the top are in

opposite directions. This causes the train to be repelled up by the bottom loop

and attracted up by the top loop.

Propulsion coil – coil in the guide way that creates a magnetic field that pulls and

pushes the train forward using the attraction and repulsion of magnets.

9.3 BOOKS :-

Integrated Electronics Multiman Halkias.

OP-Amps their design and applications Tobbey et all

OP-Amps and Linear Integrated circuit R.A. Gayakwad

Automatic Control System B.C. Kuo

Basic electronics V. K. Mehta

Data Communication Behrouz A. Forouzan

CHAPTER 10

APPENDIX

Appendix (85)

CHAPTER 10 APPENDIX

APPENDIX 10.1

Appendix for chapter 4 (MAGNETIC PROPULSION)

Appendix (86)

APPENDIX 10.2

DATA SHEETS:-

Data sheet for ULN 2803 .

Appendix (87)

Outline diemensions fo ULN 2803

Appendix (88)

APPENDIX 10.3

LM324:

Internal structure

Appendix (89)

APPENDIX 10.5

555 Timer :

Appendix (90)

maglev

Documents

Transcript of maglev