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# Maglev trains

By Akshay Jain

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### Maglev trains

1. 1. Presented by : AKSHAY JAIN 2010UME197
2. 2. PLAN OF PRESENTATION Introduction  Magnetic levitation  Basic principle & type of magnetic trains  Electromagnetic suspension  Electrodynamics suspension  Advantage of maglev transportation system  Current projects  Applications  Conclusion  References 
3. 3. INTRODUCTION      Why maglev trains needeed ? increasing pollution level from automobiles Depleting fuel resources Limited range of buses and cars Need for fast  High speed trains are solution for these problems and Maglev trains are even better solution  Maglev trains are based on maglev principle and they are non contact , friction less , high speed with low maintenance cost trains.
4. 4. MAGNETIC LEVIATION  Magnetic levitation is the use of magnetic fields to levitate a metallic object.  Manipulating magnetic fields and controlling their forces can levitate an object.  Using either Ferromagnetism or Diamagnetism object can be levitated.  A superconductor is perfectly diamagnetic and electromagnets can exhibit varying levels of ferromagnetism  Most important application of Magnetic Levitation is Transrapid magnetic lift trains.
5. 5. BASIC PRINCIPLE OF MAGLEV TRAINS Maglev trains have to perform the following functions to operate in high speeds 1.Leviation 2.Propulsion 3.Lateral Guidance
6. 6. TRAINS Based on the technique used for Leviation the are two types of Maglev trains 1. Electromagnetic Suspension -Attractive 2. Electrodynamic Suspension -repulsive
7. 7. ELECTROMAGNETIC SUSPENSION(EMS)  Electromagnetic Suspension uses electromagnets to leviate the train
8. 8. PRINCIPLE OF MAGNETIC LEVIATION  In the EMS-attractive system, the electromagnets which do the work of levitation are attached on the top side of a casing When a current is passed through it, and the electromagnet switched on, there is attraction between electromagnets and due to attraction car levitates.
9. 9. PRINCIPLE OF PROPULSION  A linear electric motor (LEM) is a mechanism which converts electrical energy directly into linear motion without employing any intervening rotary components  Linear Induction Motor (LIM) is basically a rotating squirrel cage induction motor opened out flat  Instead of producing rotary torque from a cylindrical machine it produces linear force from a flat one.  LIM thrusts vary from just a few to thousands of Newtons , depending mainly on the size and rating  Speeds vary from zero to many meters per second and are determined by design and supply frequency
10. 10. A conventional rotary synchronous motor , is made up of two rings of alternating north and south magnetic poles.  The outer ring (the stator) is stationary, while the inner one (the rotor) is free to rotate about a shaft.  The polarity of the magnets on one (either) of these rings is fixed; this element is known as the field.  o The magnets of the other ring, the armature, change their polarity in response to an applied alternating current.
11. 11. Attractive forces between unlike magnetic poles pull each element of the rotor toward the corresponding element of the stator.  Just as the two poles are coming into alignment, the polarity of the armature magnets is reversed, resulting in a repulsive force that keeps the motor turning in the same direction.  The armature poles are then reversed again, and the motor turns at a constant speed in synchronism with the alternating current which causes the change in polarity 
12. 12. GAP SENSOR This attractive force is controlled by a gap sensor that measures the distance between the rails and electromagnets  This attractive force is controlled by a gap sensor that measures the distance between the rails and electromagnets 
13. 13. PRINCIPLE OF LATERAL GUIDANCE  The levitation magnets and rail are both U shaped(with rail being an inverted U).  The mouths of U face one another.  This configuration ensures that when ever a levitational force is exerted, a lateral guidance force occurs as well.  If the electromagnet starts to shift laterally from the center of the rail, the lateral guidance force is exerted in proportion to the extent of the shift, bringing the electromagnet back into alignment.
14. 14. ELECTRODYNAMIC SUSPENSION  Electrodynamic Suspension uses Superconductors for leviation,propulsion and lateral guidance
15. 15. SUPERCONDUCTIVITY Superconductivity occurs in certain materials at very low temperatures.  When superconductive, a material has an electrical resistance of exactly zero.  It is also characterized by a phenomenon called the Miessner effect. This is the ejection of any sufficiently weak magnetic field from the interior of the superconductor as it transitions into the superconducting state. 
16. 16. PRINCIPLE OF MAGNET LEVITATION •The passing of the superconducting magnets by figure eight levitation coils on the side of the tract induces a current in the coils and creates a magnetic field. This pushes the train upward so that it can levitate 1 to 7 inches above the track. •The train does not levitate until it reaches 50 mph, so it is equipped with retractable wheels.
17. 17. PRINCIPLE OF PROPULSION •The propulsion coils located on the sidewalls on both sides of the guideway are energized by a three-phase alternating current from a substation, creating a shifting magnetic field on the guideway. •The on-board superconducting magnets are attracted and pushed by the shifting field, propelling the Maglev vehicle. •Braking is accomplished by sending an alternating current in the reverse direction so that it is slowed by attractive and repulsive forces.
18. 18. PRINCIPLE OF LATERAL GUIDANCE •When one side of the train nears the side of the guideway, the super conducting magnet on the train induces a repulsive force from the levitation coils on the side closer to the train and an attractive force from the coils on the farther side. •This keeps the train in the center.
19. 19. THE SCM (SUPER CONDUCTING MAGNET) Each SCM 3 SC coils. The SCM features high reliability and high durability.  The cylindrical unit at the top is a tank holding liquefied helium and nitrogen.  The bottom unit is an SC coil alternately generating N poles and S poles. 
20. 20. An EDS system can provide both leviation and propulsion using an onboard linear motor.  EMS systems can only levitate the train using the magnets onboard, not propel it forward.  Over long distances where the cost of propulsion coils could be prohibitive, a propeller or jet engine could be used. 
21. 21. PROS AND CONS OF DIFFERENT TECHNOLOGIES TECHNOLOGY EMS (Electromagnetic suspension) PROS CONS Magnetic fields inside and outside the vehicle are less than EDS; proven, commercially available technology that can attain very high speeds (500 km/h); no wheels or secondary propulsion system needed The separation between the vehicle and the guideway must be constantly monitored and corrected by computer systems to avoid collision due to the unstable nature of electromagnetic attraction; due to the system's inherent instability and the required constant corrections by outside systems, vibration issues may occur.
22. 22. TECHNOLOGY PROS CONS EDS (Electrodynamic suspension) Onboard magnets and large margin between rail and train enable highest recorded train speeds (581 km/h) and heavy load capacity; has recently demonstrated (December 2005) successful operations using high temperature superconductors in its onboard magnets, cooled with inexpensive liquid nitrogen 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; limitations on guideway inductivity limit the maximum speed of the vehicle; vehicle must be wheeled for travel at low speeds.
23. 23. ADVANTAGES OF MAGNETIC LEVITATED TRANSPORTATION SYSTEM  Maglev uses 30% less energy than a high-speed train traveling at the same speed (1/3 more power for the same amount of energy).  The operating costs of a maglev system are approximately half that of conventional long-distance railroads.  Research has shown that the maglev is about 20 times safer than airplanes, 250 times safer than conventional railroads, and 700 times safer than automobile travel.  Maglev vehicle carries no fuel to increase fire hazard  The materials used to construct maglev vehicles are noncombustible, poor penetration transmitters of heat, and able to withstand fire.
24. 24. CURRENT PROJECTS Currently operational systems include Transrapid (Germany ) and High Speed Surface Transport (Japan ). There are several other projects under scrutiny such as the SwissMetro, Seraphim and Inductrack. All have to do with personal rapid transit  Future Projects in india : Mumbai – Delhi , Mumbai – Nagpur, Chennai – Bangalore – Mysore   Germany and Japan have been the pioneering countries in MagLev research
25. 25. OTHER APPLICATIONS  NASA plans to use magnetic levitation for launching of space vehicles into low earth orbit.  Boeing is pursuing research in MagLev to provide a Hypersonic Ground Test Facility for the Air Force.  The mining industry will also benefit from MagLev.  There are probably many more undiscovered applications!
26. 26. CONCLUSION The Maglev Train: Research on this ‘dream train' has been going on for the last 30 odd years in various parts of the world.  The chief advantages of this type of train are: Non-contact and non-wearing propulsion, independent of friction, no mechanical components like wheel, axle.  Maintenance costs decrease  The MagLev offers a cheap, efficient alternative to the current rail system. A country like India could benefit very much if this were implemented here. Further possible applications need to be explored 
27. 27. REFERENCES 1. Mamoru Taniguchi, “High Speed Rail in Japan: A Review and Evaluation of Magnetic Levitation Train,” working paper, April 2010. 2. Brandon Gilmore, Jeff Deely, “Magnetic Levitation Transportation by the use of Electromagnets in Maglev Trains,” A11, paper- 3068, April 2013. 3. http://www.railserve.com/maglev.html 4. http://www.tech-faq.com/how-does-a-maglev-trainworks.html