Maglev

INTRODUCTION Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended above another object with no support other than magnetic field.The electromagnetic force is used to counteract the effects of the gravitational force. A substance which is diamagnetic repels a magnetic field. Earnshaw’s theorem does not apply to diamagnets; they behave in the opposite manner of a typical magnet due to their relative permeability of μr < 1.Any material in which the diamagnetic component is strongest will be repelled by a magnet. pieces of pyrolitic graphaite or bismuth above a moderately strong permanent magnet. As water is predominantly diamagnetic, this technique has been used to levitate water droplets and even live animals, such as a grasshopper and a frog; however, the magnetic fields required for this are very high, typically in the range of 16 teslas.

A live frog levitates inside a 32 mm diameter vertical bore in a magnetic field of about 16 teslas at the Nijmegen High Field Magnet Laboratory.

How can you magnetically levitate objects? MAGLEV Methods 2. Repulsion between like poles of permanent magnets or electromagnets. 3. Repulsion between a magnet and a metallic conductor induced by relative motion. 4. Repulsion between a metallic conductor and an AC electromagnet. 4. Repulsion between a magnetic field and a diamagnetic substance.  5. Repulsion between a magnet and a superconductor. 6. Attraction between unlike poles of permanent magnets or electromagnets.

7. Attraction between the open core of an electromagnetic solenoid and a piece of iron or a magnet. 8. Attraction between a permanent magnet or electromagnet and a piece of iron.  9. Attraction between an electromagnet and a piece of iron or a magnet, with sensors and active control of the current to the electromagnet used to maintain some distance between them. 10.Repulsion between an electromagnet and a magnet, with sensors and active control of the current to the electromagnet used to maintain some distance between them.  

BULLET TRAINS TRANSPORTATION BY AEROPLANE IN 20th CENTURY SPEED OF BOING 777 IS ABOUT 905kph SPEED OF MAGLEV VEHICLE IS ABOUT 500kph SPEED OF CONVENTIONAL TRAIN IS ABOUT 200kph CONNECTED CITY UPTO 1000KM PARIS TO ROME IN TWO HOURS. LONDON TO NEW YORK IN 54 MINUTES.

MAGLEV VEHICLE CONSTRUCTION • BASICALLY THE CONSTRUCTION DEPENDS ON 3 DIFFERENT FORCES

• PROPULSION FORCE • LEVITATING FORCE • LATERAL GUIDING FORCE

PROPULSION FORCE • This is a horizontal force

which causes the movement of train. It requires 3 parameters.

• Large electric power • •

supply Metal coil lining, a guide way or track. Large magnet attached under the vehicle.

PRINCPLE OF LINEAR MOTOR PROPULSION FORCE

• It’s principle is similar

to induction motor having linear stator and flat rotor.

• The 3-phase supply

applied to the stator produces a constant speed magnetic wave, which further produces a repulsive force.

Maglev vehicles are propelled primarily by one of the following three options: 1. A linear synchronous motor (LSM) in which coils in the guideway are excited by a three phase winding to produce a traveling wave at the speed desired; Trans Rapid in Germany employs such a system. 2. A Linear Induction Motor (LIM) in which an electromagnet underneath the vehicle induces current in an aluminum sheet on the guideway. 3. A reluctance motor is employed in which active coils on the vehicle are pulsed at the proper time to realize thrust.

APPLICTION OF LINEAR MOTOR IN MAGLEV

HOW THE VEHICLE LEVITATES The levitating force is the upward thrust which lifts the vehicle in the air. There are 3 types of levitating systems 1. EDS system 2. EMS system 3. INDUCTRACK system

LEVITATING FORCE • Levitating force is

produced due to the eddy current in the conducting ladder by the electromagnetic interaction.

• At low speed the force due to induced poles cancel each other.

• At high speed a repulsive

force is taken place as the magnet is shifted over a particular pole.

1.EDS SYSTEM In EDS both the rail and the train exert a magnetic field, and the train is levitated by the repulsive force between these magnetic fields. At slow speeds, the current induced in these coils and the resultant magnetic flux is not large enough to support the weight of the train. For this reason the train must have wheels or some other form of landing gear to support the train until itmagnets reachesand a speed that can Onboard large margin between rail and train enable highest sustain levitation. recorded train speeds (581 km/h). km/h) This system is inherently stable Magnetic shielding for suppression of strong magnetic fields and wheels for travel at low speed are required. It can’t produce the propulsion force. So, LIM system is required.

2.EMS SYSTEM Maglev concepts using electro -magnetic suspension employ attractive forces. Magnetic fields inside and outside the vehicle are insignificant; proven, commercially available technology that can attain very high speeds (500 km/h); no wheels or secondary propulsion system needed. The separation between the vehicle and the guideway must be constantly monitored and corrected by computer systems to avoid collision due to the unstable nature of electromagnetic attraction.

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

LATERAL GUIDING FORCE • Guidance or steering refers to

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

• •

It requires the following arrangements: Guideway levitating coil Moving magnet

CONSTRUCTONAL FEATURE

WORKING OF MAGLEV

BRAKING AND CONTROL SYSTEM GENERALY TWO TYPES OF BREAKING ARE USED AERODYNOMIC BREAKING ELECTOMAGNETIC BREAKING

Varying Maglev Speed The Maglev’s speed can vary from standstill to full operating speed by simply adjusting the frequency of the alternating current. To bring the train to a full stop, the direction of the travelling field is reversed. Even during braking, there isn't any mechanical contact between the stator and the rotor.

Aerodynamic brakes

TEST VEHICLES

• ML-500, MLX01 MLU002N

MLU001

MLX01

ML100

HISTORICAL BACKGROUND • RESEARCH AND DEVLOPMENT FIRST BIGAN IN GERMANY • • • • • • •

AND JAPAN IN 1970. AFTER LABORTARY TEST THE FIRST TEST LINE WAS STARTED IN1970 IN JAPAN AND1980 IN GERMANY. FIRST TEST LINE WAS COMPLETED IN MAYAZAKI OF JAPAN IN 1977. THE RUN OF ML500 WAS SUCCESSFULLY ENDED ON MAYAZAKI TEST LINE ATTAINING 517kmph SECOND TEST LINE WAS COMPLETED IN JAPAN IN 1990 NAMED YAMANASHI TEST LINE. THE LONGEST NONSTOPTEST HAS BEEN COMPLETED OF 1674KM IN 1993 IN 450 kmph. IN GERMANY GOVERNMENT CERTIFIED THE FIRST MAG LEV FOR PUBLIC. IN 1969 USA SCIENTISTS STARTED THE RESCEACH OF MAGLEV BUT DUE TO LACK OF GOVERNMENT INTREAST IT WAS STOPPED.

Advantages of Maglev

• • • • • •

1. Quicker and efficient transport 2. No noise 3. Comfortable, smooth ride due to very little friction 4. Safe and cost-effective S. Less consumption of natural resources 6. Environment-friendly as no gas is emitted

Disadvantage

• • •

High expensive Complex control system No overlap or junction can done

comparision JAPAN MAGLEV

GERMANY MAGLEV

• ELECTRODYNAMIC TYPE • IT WORKS ON REPULSION

• ELECTROMAGNETIC TYPE • IT WORKS ON ATTRACTION

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•

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FORCE PRINCPLE LEVITATING COIL BY SUPER CONDUCTOR LEVITATION UPTO 10CM MORE SAFER THAN GERMANY VEHICLE

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PRINCPLE LEVITATING COIL BY ELECTROMAGNET LEVITATION UPTO 1CM 100 TIMES SAFER THAN CONVENTIONAL VEHICLE

ECONOMICS • HIGH INITIAL INVESTMENT ABOUT US $6/person/day EXCEPTING MAINTENANCE, SALARY & ELECTRIC CHARGE PROPOSAL • SHANGHAI TO HANGZHOU • LONDON TO GLASGOW • SHANGHAI AIRPORT LINE • CALIFORNIA TO LAS VEGAS RESEARCH • SPEED UPTO 6000 KMPH TO 8000KMPH IN VACUUM TUNNEL