Magnetic Levitation full report
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Magnetic Levitation is a way to suspend objects in air without any support, as if in defiance of gravity. An unsung phenomenon of the past which is now being put to use in a variety of interesting and useful applications. As a child we must have seen a ping pong ball being levitated on an air stream at the output pipe of a vacuum cleaner. Magnetic levitation, also known as maglev is used in a similar way to levitate objects in air without any support, using magnetic field. Levitation is the process by which an object is suspended against gravity, in a stable position, without physical contact. For levitation on Earth, first, a force is required directed vertically upwards and equal to the gravitational force, second, for any small displacement of the levitating object, a returning force should appear to stabilize it. The stable levitation can be naturally achieved by, for example, magnetic or aerodynamic forces. Though any electromagnetic force could be used to counteract gravity, magnetic levitation is the most common. Though any electromagnetic force could be used to counteract gravity, magnetic levitation is the most common. Diamagnetic materials are commonly used for demonstration purposes. In this case the returning force appears from the interaction with the screening currents. For example, a superconducting sample, which can be considered either as a perfect diamagnet or an ideally hard superconductor, easily levitates an ambient external magnetic field. In very strong magnetic field, by means of diamagnetic levitation even small live animals have been levitated.
2 The word levitation is derived from a Latin word LEVIS, which means light. Magnetic levitation is the use of magnetic fields to levitate a metallic object. By manipulating magnetic fields and controlling their forces an object can be levitated. When the like poles of two permanent magnets come near each other, they produce a mutually repulsing force that grows stronger as the distance between the poles diminishes. When the unlike poles of two permanent magnets are brought close to each other, they produce a mutually attractive force that grows stronger as the distance between them diminish. A levitation system designed around the attractive force between unlike poles would require a perfect balance between the attractive magnetic force and the suspended weight. In the absence of a perfect lift and weight force profile, the conveyance would either be pulled up toward the magnets or would fall. This simple illustration of magnetic levitation shows that the force of gravity can be counterbalanced by magnetic force.
Figure 1 A simple Magnetic Levitation
3 There are two ways of levitations are Active and Passive. In an active levitation system, electromagnets are coupled to amplifiers that receive signals from controllers. These controllers process signals from sensors that change the magnetic force to meet the needs of the magnetic system. Passive magnetic levitation systems are impractical without a stabilizing ingredient. Diamagnetic levitation can be used to add stability to passive levitation systems. The combination of passive and diamagnetic levitation is a functional approach to many magnetic levitation applications. Magnetic levitation is used in transportation particularly in monorails, and in levitating displays. Magnetic bearings have been used in pumps, compressors, steam turbines, gas turbines, motors, and centrifuges, but these complex applications require electromagnets, sensors, and control Electromagnets are also essential to magnetic levitation systems. Such systems often use a special kind of electromagnet whose coil is made of a superconducting metal. Because the coils of a superconducting electromagnet offers no resistance to the flow of electricity, no energy is wasted by the development of heat, and the magnetic field produced by the magnet can be very strong. All magnets, whether natural or electromagnets, have two poles. We all known that like poles repel and unlike poles attract. Magnetic levitation is the product of the repulsion generated as a result of two magnetic fields. An object is said to be levitated when the force created by electromagnetic repulsion equalizes the weight of the object. Technically, it's the electromagnetic force counteracting the gravitational force. Major applications of magnetic levitation are the Transportation: Maglev trains, Moving of metallic objects in steel industry: Magnetic floaters and Military applications: Rail-gun.
Types of Levitation
4 Mechanical constraint (Pseudo-levitation) with a small amount of mechanical constraint for stability, pseudo-levitation is relatively straightforwardly achieved. If two magnets are mechanically constrained along a single vertical axis, for example, and arranged to repel each other strongly, this will act to levitate one of the magnets above the other. Another geometry is where the magnets are attracted, but constrained from touching by a tensile member, such as a string or cable. Another example is the Zippe-type centrifuge where a cylinder is suspended under an attractive magnet, and stabilized by a needle bearing from below.
5 Direct diamagnetic levitation a substance that is diamagnetic repels a magnetic field. All materials have diamagnetic properties, but the effect is very weak, and is usually overcome by the object's paramagnetic or ferromagnetic properties, which act in the opposite manner. Any material in which the diamagnetic component is strongest will be repelled by a magnet, though this force is not usually very large. Earnshaw's theorem does not apply to diamagnets. These behave in the opposite manner to normal magnets owing to their relative permeability of Ã‚Âµr < 1 (i.e. negative magnetic susceptibility). Diamagnetic levitation can be used to levitate very light pieces of pyrolytic graphite or bismuth above a moderately strong permanent magnet. As water is predominantly diamagnetic, this technique has been used to levitate water droplets and even live animals, such as a grasshopper, frog and a mouse. However, the magnetic fields required for this are very high, typically in the range of 16 teslas, and therefore create significant problems if ferromagnetic materials are nearby.
The Principals of Magnetic Levitation
6 Imagine that two bar magnets are suspended one above the other with like poles (two north poles or two south poles) directly above and below each other. Any effort to bring these two magnets into contact with each other will have to overcome the force of repulsion that exists between two like magnetic poles. The strength of that force of repulsion depends, among other things, on the strength of the magnetic field between the two bar magnets. The stronger the magnet field, the stronger the force of repulsion. If one were to repeat this experiment using a very small, very light bar magnet as the upper member of the pair, one could imagine that the force of repulsion would be sufficient to hold the smaller magnet suspendedâ€levitatedâ€in air. This example illustrates the principle that the force of repulsion between the two magnets is able to keep the upper object suspended in air. In fact, the force of repulsion between two bar magnets would be too small to produce the effect described here. In actual experiments with magnetic levitation, the phenomenon is produced by magnetic fields obtained from electromagnets. For example, imagine that a metal ring is fitted loosely around a cylindrical metal core attached to an external source of electrical current. When current flows through the core, it sets up a magnetic field within the core. That magnetic field, in turn, sets up a current in the metal ring which produces its own magnetic field. According to Lenz's law, the two magnetic fields thus producedâ€one in the metal core and one in the metal ringâ€have opposing polarities. The effect one observes in such an experiment is that the metal ring rises upward along the metal core as the two parts of the system are repelled by each other. If the current is increased to a sufficient level, the ring can actually be caused to fly upward off the core. Alternatively, the current can be adjusted so that the ring can be held in suspension at any given height with relation to the core. If we hold two permanent magnets close together, we see that one of them will jump strongly toward (or away) from the other. In 1842, Samuel Earnshaw expressed the perversity of inanimate magnetic objects in his theorem. It explains this frustrating behavior will always prevent you from suspending one permanent magnet above or below another, no matter how one arranges the two magnets. However, an active control circuit can get around this problem by rapidly adjusting the magnet's strength. The general principle is straight forward: An electromagnet pulls a ball upward while a light beam measures the exact position of the ball's top edge. The magnet's lifting force is adjusted according to position. As less light is detected, the circuit reduces the electromagnet's current. With less current, the lifting effect is weaker and the ball can move downward until the light beam is less blocked. Voila! The ball stays centred on the detector! It is a small distance across the photo-detector, perhaps a millimeter or two, but this is sufficient to measure small changes in position. Of course, if the ball is removed the coil runs at full power. And conversely, if the light beam is blocked the coil is turned completely off. This device uses two photo-detectors: the "signal" detector looks for an interruption in the light beam, and the "reference" detector measures the background light. The circuit subtracts one signal from the other to determine the ball's position. The use of two detectors is my small contribution to advance the art of levitation. This design automatically compensates for changes in ambient light, and eliminates a manually adjusted potentiometer.
MAGNETIC LEVITATION SYSTEM
7 Magnetic levitation means to rise and float in air. The Maglev system is made possible by the use of electromagnets and magnetic fields. The basic principle behind Maglev is that if you put two magnets together in a certain way there will be a strong magnetic attraction and the two magnets will clamp together. This is called "attraction". If one of those magnets is flipped over then there will be a strong magnetic repulsion and the magnets will push each other apart. This is called "repulsion". Now imagine a long line of magnets alternatively placed along a track. A line of alternatively placed magnets on the bottom of the train. If these magnets are properly controlled the trains will lift of the ground by the magnetic repulsion or magnetic attraction. On the basis of this principle, Magnetic Levitation is broken into three main types of suspension or levitation; they are (a) Electromagnetic Suspension.
(b) Electrodynamic Suspension.
Figure 2 Images of Three Types of Levitation Technique
8 Maglev trains float on a cushion of air: they do not sit on a track. The reason it can do this is because there are extremely powerful magnets on the track, and there are extremely powerful magnets on the bottom of the train. It was created like this because the lack of friction the train has now can cause it to reach speeds of up to 310 miles per hour. Also the maglev train has a very aero-dynamic design so therefore it can move faster. The maglev trains do not have wheels because they float. This keeps the train from having bumps, or rocking. The magnets on the track and the train are facing so that the same pole is towards the other. This will cause the magnets to strongly repel so that will cause the train to float. There is a extremely powerful electromagnet at the end of the track that can cause the magnets on the train to go forward or backward. This would not work if the train was not floating. Maglev trains do not have engines. The magnets on the track create a large magnetic field that causes the train to move. This causes the maglev system to be very eco-friendly, saving tons of fossil fuels. The U.S. is trying to make one of these trains so we can save fuel. The reason we are having trouble doing that is they cost so much money we canâ„¢t afford them in these economic times.
Obtained Magnetic Levitation
9 It is proved that magnetic levitation cannot be obtained just by using static ferromagnetism, as the object would tend to gain instability. In order to create proper magnetic levitation condition, diamagnetic materials or superconductors have to be used. But in all these cases a little help from pseudo-levitation needs to be taken. Pseudo-levitation is a system that provides stability to the levitated object using a magnetic mechanism. For light objects, magnets made of diamagnetic materials are sufficient. The atoms of a diamagnetic substance such as silver and bismuth, doesn't have a specific dipole moment. When these objects are brought under the influence of a magnetic field, a dipole moment is induced in the direction opposite to that of the field applied. Because of this a repulsive force is generated that creates the desired levitation. Another way of obtaining magnetic levitation is by using electromagnetism. Electrodynamic fields are created when electricity is passed through a conductor. The moving charges that are created as a result of the magnetism, provides a vertical push that is equal to the gravitational pull, which in turn help to produce a stable levitation condition. Heavier objects are generally levitated by this method. Apart from these main methods, eddy currents or electrodynamic suspension, oscillating magnetic fields and permanent magnet suspension are also used.
Present and Future Use
10 Maglev train is a famous application of the maglev technology . Almost all the prominent countries have these trains as a major mode of transport in their system. Apart from this, maglev toys are also quite famous and are available in all the markets. Some of the famous maglev toys are maglev toy train, maglev toy cars, maglev clocks etc. Future might see maglev technology put to use in a variety of applications. Maglev cars are supposed to be under development. These cars wonâ„¢t require a track but would fly in air. NASA is working on a maglev catapult that is predicted to reduce the costs and launching problems of a spacecraft. Also, Maglev elevators are already made and soon be put to use in Japan and China.
Magnetic Levitation Trains
11 In today's fast-paced and technological society, efficiency is critical. One essential factor in our lives is transportation- traveling between our home and workplace-and moving goods to marketplaces- to name a few examples. Consequently, other than airplanes, the conventional methods of transport such as cars, buses, and ships, are incomparable to more advanced transportation methods, such as maglev trains. Maglev, which stands for magnetic levitation, is a system of transportation that levitates, guides, and propels trains, with magnetism. Electromagnets along the guide-way beams and magnets underneath the train allow for repulsions and attractions, which move the train along the track. Steel wheels and tracks are removed to create a frictionless ride, allowing for speeds above 500 km/h. Specifically, only magnetic fields are relevant to the maglev train. Metal coils lining a guide-way become electromagnets when an electrical current runs through them, to begin the movement of the maglev train. The magnetic field created by this electromagnet is used to levitate the train 1-10 cm above the track by repelling the large magnets attached to the underside of the train. The beams on either side of the track also contain metal coils used for propulsion. Once the train begins to levitate, an electric current is supplied to these propulsion coils, which creates a combination of magnetic fields that push and pull the train along the track. The electric current in these coils constantly alternate to change to polarity of the electromagnets. This change in polarity causes the magnetic field in front of the train to pull it forward, while the magnetic field behind it adds more forward thrust. It is the lack of friction and the train's aerodynamic design that allow for speeds over 500 km/h. All can benefit from the maglev train, and especially those who travel regularly. The benefit extends to individuals, allowing people to reach their destinations quickly and efficiently. In addition, the benefit also extends to the country, by allowing for the employment of engineers in many countries around the world to perfect new construction methods, being a source of revenue for the country, and by reducing energy consumption, air pollution, and noise pollution. Unfortunately, maglev trains have also had a negative impact on society. The track of a Maglev train is small compared to those of a conventional train and is elevated above the ground so the track itself will not have a large effect on the topography of a region. Since a Maglev train levitates above the track, it will experience no mechanical wear and thus will require very little maintenance. Ultimately, maglev trains have the potential to change the lives of people around the world, with unprecedented ground transportation speed.
Magnetic Levitation Wind Turbine
12 Magnetic levitation is a method by which an object is suspended above another object with no support other than magnetic fields. The electromagnetic force is used to counteract the effects of the gravitational force. Magnetic levitation is used to reduce the energy loss due to friction. This energy wasted in friction can be saved by maglev method. Windmill is having maximum overall efficiency of 30%. Energy efficient windmill can operate in the maximum efficiency of 45%. The remaining energy is mainly lost in friction. If the same windmill is operating at 50% of its maximum speed the efficiency becomes very low and the frictional loss gets increased compared to power generated. The drawback of windmill is that it cannot be operated at its full capacity all the time. Wind energy has been identified as one of the green energies, the future world depends. Many countries started investing more money in wind generation. So losses in windmill shall be reduced to tap the maximum power from wind. To reduce the loss, maglev method can be implemented. Moreover due to friction there will be wear and tear in machines. Due to the wear and tear the performance of the machine will deteriorate. Hence windmill using magnetic levitation has more life than ordinary windmill. Normal windmill can start its generation from wind speed of 3 m/s. But windmill using magnetic levitation can start generation from wind speed of 1.5m/s. Operation of windmill at lower speeds, increases the amount of energy harvested from the windmill. Magnetic Levitation Wind Turbine are also called the Regenedyne. This technique is efficient, frictionless, a single unit capable of producing the power of 500 standard commercial turbines, maglev technology was said to have it all.
FIGURE 3 Magnetic Levitation Wind Turbines
13 Magnetic levitation is a phenomena that is likely to have considerable potential in the future. Particularly through the use of superconductive levitation. A new idea for magnetic levitation is in the use of storage of energy. Very basically it uses a rotating ring (flywheel) that stores (kinetic) moving energy which can be 'extracted'. It is use of magnetic fields to levitate a metallic object .By manipulating magnetic fields and controlling their forces an object can be levitated. Because of the growing need for quicker and more efficient methods for moving people and goods, researchers have turned to a new technique, one using electromagnetic rails and trains. This rail system is referred to as magnetic levitation, or maglev. Maglev is a generic term for any transportation system in which vehicles are suspended and guided by magnetic forces. Instead of engines, maglev vehicles use electromagnetism to levitate (raise) and propel the vehicle. There is much work to be done in the Maglev industry, but the basic physics argue that these new systems will penetrate the transportation system because of weight and efficiency over the ever present wheel. One other variation that might surface in the near future is a hybrid system, one in which magnets are employed to simply lighten the effective load placed on the wheels. Railways using Maglev technology are on the horizon. They have proven to be faster than traditional railway systems that use metal wheels and rails and are slowed by friction. The low maintenance of the Maglev is an advantage that should not be taken lightly. Energy saved by not using motors running on fossil fuels allows more energy efficiency and environmental friendliness. Maglev will have a positive impact on sustainability. Using superconducting magnets instead of fossil fuels, it will not emit greenhouse gases into the atmosphere. Energy created by magnetic fields can be easily replenished. Maglev will contribute more to our society and our planet than it takes away. Considering everything Maglev has to offer, the transportation of our future and our childrenâ„¢s future is on very capable tracks.
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Magnetic Levitation.ppsx (Size: 2 MB / Downloads: 717) MAGNETIC LEVITATION
DRIVING WITHOUT WHEELS
S.LAKSHMI NARAYANA REDDY
Maglev, or magnetic levitation, is a system of transportation that suspends, guides and propels vehicles, predominantly trains, using magnetic levitation.
Trends in increased mobility of large masses with changing lifestyle for more comfort are leading to congestion on roads with automobiles.
Besides, increasing pollution levels from automobiles, depleting fuel resources, critical dependence on the fuel import .
The highest recorded speed of a Maglev train is 581 kilometers per hour (361 mph), achieved in Japan.
Development of magnetic levitated transport systems is under progress in developed countries.
The need for fast and reliable transportation is increasing throughout the world. High-speed rail has been the solution for many countries. Trains are fast, comfortable, and energy-efficient.
Maglev research and development began in Germany and Japan during the early 1970's. After laboratory tests in both countries, a test track was constructed in Japan during the mid-1970's and in Germany during the mid-1980's
Maglev tech is a relatively new transportation tech in which non contacting vehicles travel safely at speeds of 250 to 300mph or higher.
The forces acting on an object in any combination of gravitational, electrostatic, and magneto static fields will make the object's position unstable.
It is possible to levitate superconductors and other diamagnetic materials, which magnetize in the opposite sense to a magnetic field in which they are placed.
As Superconductors are perfect diamagnets and when placed in an external magnetic field expel the field lines from their interiors
PRINCIPLE OF OPERATION
Imagine that two bar magnets are suspended one above the other with like poles directly above and below each other. Any effort to bring these two magnets into contact with each other will have to overcome the force of repulsion that exists between two like magnetic poles.
The magnetized coil running along the track, called a guideway, repels the large magnets on the train's undercarriage, allowing the train to levitate between 0.39 and 3.93 inches (1 to 10 cm) above the guideway.
power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway.
Levitation is the process by which an object is suspended against gravity in a stable position.
First thing a maglev system must do is get off the ground, and then stay suspended off the ground.
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 gap between the bottom of the vehicle and the rail is only 3/8"
In the EDS-repulsive system, the superconducting magnets (SCMs), which do the levitating of the vehicle, are at the bottom of the vehicle, but above the track.
The magnetic field of the superconducting magnets aboard the maglev vehicle induces an eddy current in the guideway.
Choice of linear induction motor
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.
Linear Synchronous Motor
LSM generate propulsive force by running current through a stator, which creates an electro-magnetic field.
This electro-magnetic field interacts with a set of permanent magnets on a vehicle to create thrust.
The permanent magnets serve as the motor secondary, equivalent to a rotor in conventional motors enabling linear motion.
The vehicle is propelled by the moving electro-magnetic field, traveling along as electric current is applied to the stator beneath the vehicle.
The vehicleâ„¢s movement is regulated by a sophisticated control system incorporating state-of-the-art position sensing technology.
Synchronous vs Induction motors
Far more effort has been put into research and development of linear induction motors (LIM's) than LSM's.
LIM's do indeed have two distinct advantages. First of all, they are simpler and less costly to construct.
The stationary element of the motor consists of nothing more than a rail or plate of a conducting material, such as aluminum.
By contrast, LSM's require the installation of alternating north and south magnetic poles on both moving and stationary elements.
Linear induction motor (LIM) in magnetic levitation
The High Speed Surface Transport (HSST) system is propelled by linear induction motor.
The HSST levitation system uses ordinary electromagnets that exerts an attractive force and levitate the vehicle.
Characteristics of LIM
In most vehicular propulsion systems, provision must be made for increasing the power when the demand increases.
Whenever more power is needed, the moving magnet begins to lag further behind the stationary one; this results in an immediate increase in thrust. No separate control is needed
Benefits of Magnetic Levitated Transportation system
Power of the maglev motor is dependent on the local conditions.
Maglev uses 30% less energy than a high-speed train traveling at the same speed.
Operating costs of a maglev system are approximately half that of conventional long-distance railroads.
Maglev is about 20 times safer than airplanes, 250 times safer than conventional railroads, and 700 times safer than automobile travel.
Despite the speeds up to 500 km/hour, passengers can move about freely in the vehicles
Materials used to construct maglev vehicles are non-combustible, poor transmitters of heat, and able to withstand fire penetration.
Carries no fuel to increase fire hazard
The train makes little noise because it does not touch the track and it has no motor. Therefore, all noise comes from moving air. This sound is equivalent to the noise produced by city traffic.
Germany and Japan have been the pioneering countries in MagLev research. Currently operational systems include Transrapid (Germany) and High Speed Surface Transport (Japan). There are several other project and implimentations under scrutiny such as the SwissMetro, Seraphim and Inductrack. All have to do with personal rapid transit.
The Maglev Train: Research on this Ëœdream trainâ„¢ 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. Low noise emission and vibrations at all speeds.
2. Magnetic levitation
3. Levitation principle
4. Lateral guidance
5. Maglev track
7. Linear electric motor
8. LIM in levitation
9. Characteristics of LIM
11. Current project and implimentations
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29-03-2011, 10:02 AM
thank you, report is very useful
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21-04-2011, 03:27 PM
MAGNETIC LEVIATION ENGINE.doc (Size: 49 KB / Downloads: 153)
MAGNETIC LEVIATION ENGINE
In this fast moving world, there is always a necessity for invention. Our paper aims at the improvement of automobile engine efficiency, reduction in consumption of fossil fuels and thereby decreasing air pollution. In contrary with the conventional internal combustion engine, our Maglev Automobile Engine is based on the principle of Magnetic Levitation. Here, the motion of the piston is achieved with the help of attractive and repulsive forces of a magnet. As we use the levitation principle, losses due to friction is almost reduced to zero. Aiming at a better efficiency, we put forward this idea for future enhancements.
Introduction & Necessity:
The need for the non-renewable fossil fuels is increasing day-by-day, and our goal is to minimize our dependence on fossil fuels. Gasoline or diesel powered IC engines are the most common but require constant re-fuelling and generally, they are not eco-friendly. Moreover, achieving the magical 100% efficiency barrier is the major task ahead of the modern day engineers. Accordingly, there is always a need for the source of power, which is not reliant solely on the fossil fuels and do not cause damage to the environment through any forms of pollution
Internal Combustion Engine:
In the present world, almost all the automobiles are running with the help of internal combustion engines. An internal combustion engine is an engine, in which combustion occurs directly through fossil fuels mixed with an oxidizer (mostly air) in a combustion chamber. In an IC engine, the expansion of fuel is used to move the piston inside the engine cylinder. The crank shaft transforms the to and fro motion of the piston to rotary motion. This rotary motion of crank shaft is then transmitted to the wheels with the help of the shafts and gear assembly.
Magnetic levitation is the process of lifting or hovering of a magnetic material by a strong magnet. This principle is used in maglev trains, superconducting bearings and in turbo-molecular pumps. The levitation of the magnetic material is achieved with the help of both the attractive and repulsive forces of a magnet, which is used to counteract the influence of the gravitational forces. Electromagnets can be used for levitation, as the magnetic field can be varied by varying the current flow according to our requirements.
Super-conducting materials can be used as Electromagnets, as they can increase the magnetic flux, for the same amount of magnetic field. The levitation of the magnet is further stabilized due to flux pinning within the superconductor. This tends to stop the superconductor leaving the magnetic field even if the levitated system is inverted. This phenomenon helps us greatly in our maglev engine.
Magnetic levitation in bullet trains.
Components required for the engine assembly:
The electromagnets are used for levitating the piston inside the cylinder. The electromagnets are fixed on the walls of the cylinder, to produce magnetic field around the piston. To reduce flux loss in the electromagnet, it is fully laminated. The electromagnet must be supplied with a varying AC current. The polarity of the magnetic field changes according to the frequency of the input ac current. The core of the electromagnets can be within the voltage ratings as prescribed in the battery.
Lithium-ion rechargeable battery with ratings as 110 to 192V & 10amps, with 180Ah can be used for supplying current to the electromagnet. This can be recharged through electric recharging stations or even in our homes, by a charging assembly.
As the battery supplies DC, an inverter is connected to convert DC to AC and is fed to the electromagnet assembly in the engine. The frequency of the output AC can be varied by the inverter by using PWM (Pulse Width Modulation) technique. It uses four MOSFET switches to vary the frequency of the ac signal. The frequency of the AC plays a major role in the velocity of the piston, which will be dealt in the upcoming pages of our paper.
Halbach array of magnets:
The Halbach array is a special arrangement of permanent magnets, which is used to confine the magnetic flux to one direction. This array of magnets is fixed on the walls of the piston. This ensures the concentration of the magnetic flux of the permanent magnet is only around the piston, and not towards the piston. This flux is used for the levitation of the piston. The usageof the Halbach array of arranging magnets increases the magnetic flux of the permanent magnet. Flux losses will be minimum in this type of arrangement. These are used in particle accelerators, free electron lasers and in inductrack maglev trains
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your work was very interesting and transparent it would be a pleasure to receive your work and info to gain up knowledge in the magnetic levitation. pls forward the report!
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Magnetic levitation is the latest in transportation technology and has been the interest of many countries around the world. The idea has been around since 1904 when Robert Goddard, an American Rocket scientist, created a theory that trains could be lifted off the tracks by the use of electromagnetic rails. Many assumptions and ideas were brought about throughout the following years, but it was not until the 1970’s that Japan and Germany showed interest in it and began researching and designing.
The motion of the Maglev train is based purely on magnetism and magnetic fields. This magnetic field is produced by using high-powered electromagnets. By using magnetic fields, the Maglev train can be levitated above its track, or guideway, and propelled forward. Wheels, contact with the track, and moving parts are eliminated on the Maglev train, allowing the Maglev train to essentially move on air without friction.
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The use of natural resources in our day to day life is increasing which leads to shortage of these resources in the upcoming generation,mainly in transportation we are wasting a lot of crude oils and other resources which leads to global earthing. So in this paper we’re discussing about magnetic levitation and the uses in transportation .
Magnetic levitation is being used in ultrahigh speed trains(upto 300km/h) which float in
the air about 100mm to 300mm above the metallic track.they do not have any wheels and do not require the traditional steel rail.A powerful electromagnet (whose coils are cooled to about 4degree K by liquid helium) fixed underneath the train moves across the conduc- ting rail,thereby inducing current in the rail. This gives rise to vertical force (called force of levitation) which keeps the train pushed up in the air above the track linear motors are used to propel the train.
A similar magnetic levitation system of transit is being considered for connecting vivek -vihar in east Delhi to vikaspuri in west Delhi. The system popularly known as magneto-bahn (M-Bahn) completely eliminates the centuries-old ‘steel-wheel-over steel rail’ tra- ction. The M-Bahn train floats in the air through the principle of magnetic levitation and propulsion is by linear induction motors. There is 50% decrease in the train weight and 60% reduction in energy consumption for propulsion purposes. The system is extraordin- arily safe (even during an earthquake) and the operation is fully automatic and computer- ised
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30-05-2012, 12:59 PM
Overcoming the grip of Earth’s gravity is a supreme
challenge for engineers who design rockets that leave the planet. One of the cutting-edge technologies being
developed at NASA’s Marshall Space Flight Center in Huntsville, Ala., would give launch vehicles a "running
start" as they lift off to orbit.
Marshall engineers are testing magnetic levitation—or maglev—technologies that could levitate and accelerate
a launch vehicle along a track at high speeds before it leaves the ground. Using electricity and magnetic fields,
a maglev launch-assist system would drive a spacecraft along a horizontal track until it reaches desired
speeds, and then the vehicle would shift to onboard engines for launch to orbit. A full-scale, operational track
would be about 1.5 miles long and capable of accelerating a vehicle to 600 mph in 9.5 seconds.
Maglev technologies could dramatically reduce the cost of getting to space. Much of the expense of
conventional rocket launches is traced to the weight of propellant. Since maglev-assisted vehicles use
electricity—an off-board energy source, the spacecraft’s weight at liftoff could be about 20 percent less than a
typical rocket, resulting in significant cost savings. Each launch using a full-scale maglev track would consume
only about $75 worth of electricity in today’s market. Electricity is both inexpensive and environmentally safe.
The Marshall Center and industry partner PRT Advanced Maglev Systems Inc. of Park Forest, Ill., installed a
50-foot maglev track at Marshall in September and plan to extend it to 400 feet. Tests conducted with the
experimental track help NASA learn more about aerodynamics, magnetic fields and energy storage devices
associated with maglev. Experiments to validate the concept have been conducted successfully on a 20-foot
electromagnetic track at the University of Sussex in Brighton, England.
The Marshall track is an advanced linear induction motor. Induction motors are common in fans, power drills
and sewing machines, but instead of spinning in a circular motion to turn a shaft or gears, a linear induction
motor produces thrust in a straight line. It’s basically a rotary motor split in half and rolled out flat.
When the coils of the linear induction motor are energized by alternating current, a magnetic field is created,
providing thrust that pushes an aluminum carrier along the maglev track. A horseshoe-shaped carrier
containing a 5-foot, 30-pound spacecraft model is levitated about one-half inch above the track as it accelerates
from zero to 60 mph in less than one-half second.
The track—50 feet long, about 2 feet wide and about 1.5 feet high—is mounted on concrete pedestals. It
consists of 10 identical, 5-foot-long segments that weigh about 500 pounds each. Most of the weight is iron
used in the motor. The track is shrouded with nonmagnetic stainless steel.
Magnetic levitation of the carrier and its vehicle on the experimental track requires about 200 kilowatts of
electricity—the equivalent of turning on 2,000 100-watt light bulbs at one time.
In addition to industry partner PRT, NASA is joining with Lawrence Livermore National Laboratory of Livermore,
Calif., to develop maglev technologies. The Livermore team is building a track that uses permanent magnets
and a linear motor that runs without superconductors or complex feedback circuits.
Maglev is one of many technologies being developed by the Marshall Center’s Advanced Space Transportation
Program to reduce the cost of getting to space from today’s $10,000 per pound to only hundreds of dollars per
Joined: Apr 2012
04-08-2012, 04:18 PM
This document has been prepared by a team of Mechatronics undergraduate student
to explain the concept of a new technology (Maglev) that involves lifting a body and suspending it mid-air using the very basic laws of physics and magnetism.
In this document you will be able to understand how the maglev technology works and how its implemented on a robotic arm. By explain the technology by building a small machete to demonstrate how to lift a metal object and sustain the levitation effect of the object using a control circuit that adjusts the strength of the magnetic field generated which is mounted in a later stage to an end effector of a robotic arm. Also, some of the applications and uses that can be applied within that field.
Joined: Apr 2012
04-10-2012, 01:28 PM
In Maglev.docx (Size: 12.94 KB / Downloads: 18)
In Maglev—which is short for MAGnetic LEVitation—high speed vehicles are lifted by magnetic repulsion, and propelled along an elevated guideway by powerful magnets attached to the vehicle. The vehicles do not physically contact the guideway, do not need engines, and do not burn fuel. Instead, they are magnetically propelled by electric power fed to coils located on the guideway. FIRSTLY, Maglev is a much better way to move people and freight than by existing modes. It is cheaper, faster, not congested, and has a much longer service life. A Maglev guideway can transport tens of thousands of passengers per day along with thousands of piggyback trucks and automobiles. Maglev operating costs will be only 3 cents per passenger mile and 7 cents per ton mile, compared to 15 cents per passenger mile for airplanes, and 30 cents per ton mile for intercity trucks. Maglev guideways will last for 50 years or more with minimal maintenance, because there is no mechanical contact and wear, and because the vehicle loads are uniformly distributed, rather than concentrated at wheels. SECONDLY,Maglev vehicles emit no pollution. When they consume electricity, no carbon dioxide is emitted. Even if they use electricity from coal- or natural-gas-fired power plants, the resulting CO2 emission is much less than that from autos, trucks, and airplanes, because of Maglev’s very high energy efficiency.
Joined: Oct 2012
17-12-2012, 01:41 PM
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