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MAGLEV –MAGNETIC
LEVIATION
Driving without wheels, Flying without
wings
Under the Esteemed Guidance of
MAGNETIC LEVIATION
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Magnetic levitation is the use of magnetic fields
to levitate a (usually) metallic object.
Manipulating magnetic fields and controlling
their forces can levitate an object.
Using either Ferromagnetism or Diamagnetisim
object can be leviated.
A superconductor is perfectly diamagnetic and
electromagnets can exhibit varying levels of
ferromagnetism
Most imoportant application of Magnetic
Leviation is Transrapid magnetic lift trains.
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
TYPES OF MAGLEV TRAINS
Based on the technique used for Leviation the are
two types of Maglev trains
1. Electromagnetic Suspension -Attractive
2. Electrodynamic Suspension -repulsive
ELECTROMAGNETIC
SUSPENSION(EMS)
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Electromagnetic Suspension uses electromagnets
to leviate the train
PRINCIPLE OF MAGNETIC
LEVIATION
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In the EMS-attractive system, the
electromagnets which do the work of levitation
are attached on the top side of a casing that
extends below and then curves back up to the rail
that is in the center of the track.
The rail, which is in the shape of an inverted T, is a
ferromagnetic rail.
 When a current is passed through it, and the
electromagnet switched on, there is attraction, and the
levitation electromagnets, which are below the rail, raise
up to meet the rail. The car levitates.
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PRINCIPLE OF PROPULSION
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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
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.
 The magnets of the other ring, the armature,
change their polarity in response to an applied
alternating current.
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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
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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
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PRINCIPLE OF LATERAL
GUIDANCE
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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.
ELECTRODYNAMIC
SUSPENSION
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Electrodynamic Suspension uses
Superconductors for leviation,propulsion and
lateral guidance
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.
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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 10 cm above the track.
•The train does not levitate until it reaches 50 mph, so it is
equipped with retractable wheels.
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.
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.
THE SCM (SUPER CONDUCTING
MAGNET)
Each SCM 4 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.
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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.
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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.
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.
ADVANTAGES OF MAGNETIC
LEVITATED
TRANSPORTATION
SYSTEM
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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.
CURRENT PROJECTS
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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
Germany and Japan have been the pioneering
countries in MagLev research
OTHER APPLICATIONS
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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!
CONCLUSION
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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
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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
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