Which principle is used in magnetic levitation

A guideway consists of a beam girder and two levitation guidance rails. Guideways can be constructed at grade ground-level or elevated including columns with concrete, steel, or hybrid beams.

Maglev elevated guideways minimize land occupation and prevent collision with other forms of traffic at-grade intersections. Guideways are designed and constructed as single or double tracks Figure A majority of cross-sections of guideway girders are also U-shaped.

The rail gauges track gauges and spans are mostly 2. The most important part in the analysis and design of guideway is structural loading.

The loading of the maglev vehicle is an important parameter in the practical application. It is related to the magnetic forces.

The guideway must carry a dead load due to its own weight, and live loads including the vehicle loads. To incorporate the dynamic interaction between the guideway and the vehicle, the live load is multiplied by a dynamic amplification factor. Lateral and longitudinal loads including wind and earthquake loads may also need to be considered. The guideway loadings are modeled as dynamic and uniformly distributed magnetic forces to account for the dynamic coupling between the vehicle and the guideway.

Magnetic forces are generated by the maglev vehicle and cause structural loading that transmits to the guideway. This can happen whilst such a vehicle is stationary or in motion. Guideways are designed and constructed with concrete or steel girders. Concrete guideway girders can be as reinforced or prestressed. Guideway girder is evaluated for different load cases.

As an example, the Shanghai guideway girder was evaluated with respect to as many as 14, load cases by consideration of the deflection, dynamic strength, and thermal expansion. The guideway girder for Urban Maglev Program in Korea was also evaluated for five load cases that are combinations of the dead load, live load, and the prestressing forces of the tendon [ 14 , 15 ]. Despite high speeds, passengers are safer in maglev vehicles than in other transportation systems.

The electromagnetically suspended vehicle is wrapped around the guideway and therefore virtually impossible to derail. Elevated guideways ensure that no obstacles can be in the way. In order to prevent contact between the vehicle and the guideway and maintain the required gap between them, the system is continuously under Operation Control System OCS command.

The Operation Control System OCS comprises all technical facilities for planning, monitoring, and safeguarding of vehicle operation [ 16 ]. The experimental track is installed inside a high-bay facility at the Marshall Center. The vehicle would shift to rocket engines for launch to orbit. Maglev systems could dramatically reduce the cost of getting to space because they are powered by electricity, an inexpensive energy source that stays on the ground—unlike rocket fuel that adds weight and cost to a launch vehicle.

The tabletop track is 44 feet long, with 22 feet of powered acceleration and 22 feet of passive braking. A pound carrier with permanent magnets on its sides swiftly glides by copper coils, producing a levitation force. The track uses a linear synchronous motor, which means the track is synchronized to turn the coils on just before the carrier comes in contact with them, and off once the carrier passes. The testing is expected to help engineers better understand Maglev vehicle dynamics, the interface between a carrier and its launch vehicle, and how to separate the vehicle from the carrier for launch.

A Maglev system uses magnetic fields to levitate and accelerate a vehicle along a track. Similar systems are in use today as high-speed trains and some of the newer, radical-ride roller coasters. Maglev systems use high-strength electromagnets to lift a vehicle a few inches above a track and then propel it forward with high acceleration. When the spacecraft nears the end of the track, it could take off like an airplane and then switch to more conventional rocket engines to continue to orbit.

The weight of propellant is a major culprit in the high cost of conventional rocket launches. This makes getting to space less expensive. The test track at Marshall, which is 50 feet 15 meters long, about 2 feet 0.

It consists of 10 identical, 5-foot-long 1. Most of the weight is iron used in the motor. The track is shrouded with nonmagnetic stainless steel. Some time in future, a larger foot meter track will be installed at Marshall. The space tourism company Galactic Suite already has 38 reservations made by tourists who, the company says, in will travel on board a magnetically levitated spacecraft to an orbiting luxury hotel, complete with a floating spa.

The trip, which costs 3 million Euros, will provide four days in orbit kilometers above the earth and includes 18 weeks of training on a Caribbean island for the tourists to prepare for their spaceflight. After reaching approximately the speed of sound, the spaceship will detach from its maglev carrier and accelerator and will ascend to orbit using rocket or air-breathing engines.

The maglev accelerator will then brake to a stop and return to its starting point for the next launch. The launch track will be about 3 kilometers long. Maglev launch assist technology will enable space tourists to travel to our space resorts in orbit on a commercial basis. The most expensive part of any space travel to low-Earth orbit is the first few seconds—getting off the ground. This technology is cost competitive with other forms of space transportation, environmentally friendly and inherently safety.

The stay at the hotel will offer a mixed programme of reflection and exercise to seize the unique physical conditions encountered in space. One of the most innovative experiences that tourists can experience is the bathroom in zero gravity. Galactic Suite has developed the space spa. Inside the spa, tourists can float with 20 liters of water bubbles. According to Galactic Suite materials, the tourist, already trained to avoid the effects of water in a state of weightlessness, can play with the bubble dividing it into thousands of bubbles in a never-ending game.

In addition, the transparent sphere may be shared with other guests. Galactic Suite is a private space tourism company, founded in Barcelona in The company hopes to make space tourism available to the general public and will combine an intensive program of training astronauts to relax with a programme of activities on a tropical island as a process preparation to space travel.

The launch ring consists of a maglev system in which a levitated vehicle is accelerated in an evacuated circular tunnel until it reaches a desired velocity and then releases a projectile into a path leading to the atmosphere. The cost of this technology, even with partially reusable rockets, has remained sufficiently high that its use has remained limited.

There is general acceptance that a lower cost alternative to rockets would greatly increase the volume of traffic to space see Figures 17 and 18 [ 17 , 18 ]. The space elevator is probably the best-known proposed alternative technology to rockets. The usual contemporary design concept for a space elevator is based around a mechanical cable extending radially inward and outward from a geosynchronous orbit, usually with a counterweight at the outer radius and with the innermost part of the cable attached to the ground at the equator.

An elevator car can then attach to the cable and ferry people or material up or down. In principle, such a cable can be constructed by tapering the cross section from a small diameter at the ends to a very thick diameter at the geosynchronous point. In practice, the strength of presently available engineering materials makes the mass of such a cable uncomfortably large.

Most gun concepts involve short acceleration times, and the subsequent large power supplies to boost even modest masses to the required velocity are likely to be expensive. Electromagnetic launch has been proposed to give rockets an initial velocity component, with most of the required velocity provided by combustion of the propellant [ 22 ]. Ground-based, high-powered lasers that augment the chemical energy of rocket propellant will also likely require large power supplies [ 21 ].

The maglev fan provides superior performance, low noise, and long life. By using magnetic levitation forces, these fans feature zero friction with no contact between shaft and bearing. With excellent rotational stability, the maglev fan eliminates vibration and typical wobble and shaking typically experienced in fan motors. The maglev fan also provides excellent high temperature endurance that results in long life, and the maglev fan models also feature all-plastic manufacture of major items for optimal insulation resistance and electrostatic discharge ESD performance.

The maglev fan offers a true solution to equipment and systems cooling, with the promise of lower cost of ownership and long service life. The maglev fan overcomes the problems of noise, abrasion, and short service life that beset traditional fan motors.

The maglev motor fan features zero friction and no contact between the shaft and bearing during operation. The maglev fan design is based on magnetic principles and forces that not only propel the fan but also ensure stable rotation over its entire degrees of movement. Utilizing the attraction of the magnetic levitation force, maglev eliminates the wobbling and shaking problems of traditional motor fans.

With this new technology, the maglev fan propeller is suspended in air during rotation so that the shaft and bearing do not come into direct contact with each other to create friction. The result is a new and improved fan with a low noise level, high temperature endurance, and long life. Maglev fans can be used in various industries and products that require high-level heat transfer, such as notebook computers, servers, projectors, and stereo systems.

Traditional fans apply the principle of like-pole repulsion to rotate. But with no control exerted over blade trajectory, the fan blades tend to produce irregular shuddering and vibrations. After long-term use, the shaft will cause severe abrasion on the bearings, distorting them into a horn shape.

The worn-out fan then starts to produce mechanical noises and its life-time is shortened. The unique feature of the maglev fan is that the path of the fan blades during operation is magnetically controlled. The result is that the shaft and bearing have no direct contact during operation and so experience no friction no matter how the fan is oriented. This means that the characteristic abrasion noises of worn-out components are not produced and also allow a service life of 50, hours or even longer at room temperature see Figure In a traditional fan, the embedded magnets of the rotor and the stator exert repulsive forces, and it is this continuous force of repulsion that makes the fan spin.

This is the basic principle behind all cooling fans. If we visualize the magnetic forces between the stator and the rotor, we see only dense lines of standard magnetic flux running without any control mechanism to stabilize vibration of the blade rotor during the repulsion-driven operation.

The maglev fan includes just such a control mechanism in its design. This requires that each fan, in addition to standard magnetic flux, contains maglev flux required to sustain for the unique maglev orbit in its design. A maglev cross-section view reveals a uniquely designed set of conductive elements on the main board—the maglev plate.

This maglev plate and the embedded magnets in the fan blades together generate comprehensive vertical magnetic forces, which is the maglev flux. From the cross-section, the standard magnetic flux and maglev flux form a degree vertical angle, in others words, the maglev flux acts perpendicular to the standard magnetic flux.

This is the first key trait to use to identify a maglev fan. The design of vertically intersected standard magnetic flux and maglev flux ensures that the rotator is affixed to the maglev orbit. Therefore, regardless of the mounting angle of the fan, the shaft will always rotate around a fixed point and at a constant distance from the bearing without coming in contact with it to produce friction or mechanical noise.

The problem of bearings being worn down into an oval shape or horn aperture after long use is effectively resolved. The greatest benefit with maglev flux is in fact the degree complete force of attraction between the conductive element maglev plate and the rotor above it. This ensures an evenly distributed force of attraction to help keep the optimal balance of the rotor during operation and to avoid shuddering or instability.

Fans with well-balanced blades not only last longer but produce a steady air flow. In the traditional DC brush-less fan motor design, the impeller rotor simply called Rotor by means of a shaft which extended through the bore of oil-impregnated bearing, or sleeve bearing, pivotally held in the center position of motor stator. A suitable air gap was maintained between the rotor and the stator. Of course, there must be gap between shaft and bearing bore, otherwise, the shaft would be tight-locked and unable to rotate.

The stator assembly simply called stator after connection to power supply will generate induced magnet flux between rotor and stator.

With the control of driving circuitry the fan motor will start to rotate. In a traditional fan motor structure, there is an impeller rotor, a motor stator, and a driving circuitry. The rotor is pivotally joined to the stator by the rotor shaft and bearing system. The rotor is driven to rotate by the induced magnetic field between stator and rotor as shown in Figure Advantages of sleeve bearing are the following. Imperfections of sleeve bearing are the following.

The inner surface of bearing bore easily gets worn and influences the performance. The space between the shaft and sleeve-bearing bore is small this results in rough uneven start-ups. Ball bearing workings utilize small metal balls for rotation. Since they have only point-contacts, rotation can be started easily. With the use of springs to hold the outer metal ring of the ball bearing above, the weight of the entire rotor can sit on the ball bearing, indirectly supported by the springs. Therefore, ball bearings are ideal for use in portable devices with various mounting angles.

However, caution should be used to prevent the product from falling and impact damaging the ball bearing, which could lead to noise and shortened product life-time see Figure Advantages of ball bearing are the following.

Imperfections of ball bearing are the following. It cannot bear any external impact. When a spinning top a kind of toy is thrown, the top continues to accelerate even as it hits the ground. During this acceleration the top tilts and sways until a consistent speed is obtained. At this point, the top will balance itself, for example, the swaying and tilting have faded and have become fixed perpendicular to the ground. This is the simple concept that maglev fan system roots form see Figure From the illustration above, we know that no matter how the motor fan is mounted, the force induced by the existing magnet inside the hub and the magnetic plate that is added to the PCB of the fan attracts the rotor continually.

This results in the rotor rotating perpendicular to the ground with a constant distance between bearing and shaft without any contact. Therefore, no rubs or noise can occur. The operating life of the motor fan is extremely long see Figure Consequently, the shaft inside the Vapo bearing bore turns without creating friction. The bearing bore is hardly ever abraded into irregular or oval shapes such as seen in conventional fans. Hence the operating life of the bearing becomes very long.

There are no more clogging problems. Hence, the fan motor may operate smoothly for quite a long time. When used in conjunction with the maglev, it creates a spring function, which helps the fan motor to bear impact. It also performs very well in a low temperature environment.

With the combination of maglev design and Vapo bearing, all the advantages of ball and sleeve bearings are maintained, while eradicating all the imperfections. Vapo Bearing can be explained as follows.

No vibration occurred. Vapo bearing is named after this character. Maglev fans prevent the defects of conventional fans see Table 1. There is no friction and contact between the shaft and the bearing during operation. They have become favorite due to its superior features such as low noise, high temperature endurance, and super long life.

The axial-flow radial-flux permanent magnet motor along with an iron strip segment, as shown in Figure 25 , has been used for small-power cooling fan applications [ 23 ]. This motor is equipped with only one set of axial stator winding that can supply the desired radial flux through adequate stator pole design, and such structure design is quite promising for applications with limited spaces.

With the undesired vibration forces mainly generated in the motor radial direction, the concept is to provide adequate flux path such that a passive magnetic suspension can be established.

With the pole pairs on the stator top and bottom parts being perpendicular to one another, undesired vibration forces mainly generated in the motor radial direction will be exhibited.

The resultant frictions applied onto motor bearing system will certainly generate extra heat and energy losses and thus reduce the reliability and lifetime of this motor [ 24 , 25 ]. In addition, to satisfy these construction prerequisites, it is also desired that the overall performance of such motors can preserve their market competitions without implementing complicate sensor and driver control devices. A magnetic suspension will be established through the extra flux path being provided.

Though it is anticipated that the attraction force between the rotor permanent magnet and the passive magnetic suspension segment will be induced to stabilize the rotor vibrations, intuitively it is also suspected that this segment with high permeability might yield the motor rotational performance [ 25 ].

Heat failure is one of the main causes of death. Treatments of heart failure generally have heart transplantation, ventricular mechanical assistance, artificial organs substitution, and so on. Although heart transplantation is a relatively nature technology, there is a serious shortage of donated hearts and will result in transplant rejection reaction. The support of traditional artificial heart pumps often uses rolling or sliding bearings. Because of the contact between bearing and blood, the blood will be polluted and will easily produce thrombosis.

With the development of maglev, motor and control technology, artificial heart pump overcome the problems such as friction, sealing, and lubrication, which reduced the damage of blood cells and improved the heart pump life and safety.

Artificial heart pump requires small structure, low energy consumption, certain stiffness and damping for transplanting, and long time using. A hybrid-type axial maglev blood pump not only has small size, almost no energy, and poor dynamic characteristics of permanent magnet bearing but also has low power consumption, long life, and good dynamic characteristics of magnetic bearing. Artificial heart pump also known as blood pump can be divided into displacement, pulsating, and continuous-flow heart pump.

The bionic performance of pulsating pump is good but its disadvantages are relatively large volume and will be prone to hemolysis because it has big blood contact area.

These shortcomings seriously restricted its application. Continuous-flow artificial heart pump can be divided into axial flow pump, centrifugal pump, and mixed flow pump. Maglev centrifugal heart pump has a greater pressure in a small flow rate and has fewer destruction to blood in low speed, while its disadvantage is not suitable for implantation; the axial maglev heart pump has a big flow rate, low pressure, which need to increase speed for obtaining much greater pressure. Axial flow pump has a tight structure, smaller drive components, low power consumption, light weight, high efficiency, and so forth, so it is easier to implant and can save the cost of the surgery and the possibility of infection, but its impeller has a high speed and its hemolytic is also high.

Either axial or centrifugal, the traditional supports are contacted bearings such as ceramic bearing, and there are some problems about friction, lubrication, and sealing which is easy to damage the blood, leading to hemolysis and blood clots. The magnetic bearing avoid, contact of rotor and stator by the magnetic force which does not need lubrication and overcome the traditional shortcomings such as direct friction, big loss, and short life, and it is one of the ideal support for a new generation of artificial heart pump [ 27 , 28 ].

This theorem is applicable only to a levitator in static state. A passive magnetic PM bearings could achieve stable maglev in all centrifugal pumps, if the rotor had high enough speed and thus obtained a so-called gyroeffect, namely, a rotating body with high enough speed could maintain its rotation stably [ 29 , 30 ].

To simplify the electrically maglev rotary pumps, a shaft-less full-permanent maglev impeller pump without actively controlled coil for rotor suspension has been developed Figure The device consists of a stator and a rotor. The stator has a hard polyurethane housing with cylindrical inner surface; on its left side an axially driven DC motor coil winded on an iron core is connected and on its right side a balancing iron ring is screwed.

The rotor is compacted by a magnet disc for rotation in the left , an impeller in the middle , and a magnet disc for suspension in the right. The attractive force between the motor coil iron core and the rotor magnet disc for rotation is balanced by the attractive force between the magnet disk for suspension and the balancing iron ring.

Furthermore, two novel patented permanent magnetic bearings are devised on both sides of the rotor, eliminating the remaining attractive forces and preventing the rotor being affiliated axially to the stator either in the left or in the right.

Each bearing is composed of a small and a big permanent magnetic ring; the small ring is inlaid into the rotor and the big ring is buried in the stator. Two rings magnetized in the same axial direction reject each other, providing an axial bearing force. The attractive force between the rotor and the stator resists the radial eccentric movement of the rotor and thus serves as a radial bearing.

The inlet and outlet of the pump are located respectively in the center of the balancing iron ring and onto the periphery of the PU housing. Implantable rotary pumps have been developed and used to assist the impaired heart ventricle because of lack of heart donors for transplant.

Pulsatile flow rate measurement is important for controlling the flow rate of these rotary pumps. Conventional flow meters are not particularly compact, while the reliability and durability of small flow meters made using microelectromechanical system technology is still uncertain.

Several groups have proposed estimating flow rate using the motor power of the centrifugal blood pump CBP. Figure 27 a shows a schematic of an implantable ventricular assist system using a rotary pump [ 32 ]. Key attributes of the PediaFlow Pediatric VAD include the following: i unparalleled biocompatibility due to the maglev technology, streamlined single-flow-path design, and computer-optimized design process; ii exceptionally small due to the supercritical above resonance frequency rotordynamic technology; iii valveless turbodynamic design with one moving part to minimize size; iv computationally optimized using first principles of bioengineering and physics.

The current VAD design arose from the comprehensive evaluation of three pump topologies incorporating a variety of magnetic suspension, motor, and fluid path arrangements. Each of the selected topologies utilized permanent magnet radial and moment bearings, an active axial thrust bearing, and a brushless DC motor [ 33 — 36 ].

Existing devices for making those measurements are far from ideal, and a need exists for simpler, less expensive, and easy-to-use technology.

Scientists describe development of a special sensor that uses maglev to meet those needs, suspending solid or liquid samples with the aid of magnets to measure their density.

About the size of an ice cube, the sensor consists of a fluid-filled container with magnets at each end. Samples of different materials can be placed inside, and the distance they migrate through the fluid provides a measure of their density. Scientists showed that the device could quickly estimate the salt content of different water samples and the relative fat content in different kinds of milk, cheese, and peanut butter.

Potential applications of maglev may include evaluating the suitability of water for drinking or irrigation, assessing the content of fat in foods and beverages, or monitoring processing of grains e. It has various uses, including clean energy small and huge wind turbines: at home, office, industry, etc. The common point in all these applications is the lack of contact and thus no wear and friction. This paper tried to study the most important uses of magnetic levitation technology.

The results clearly showed that the maglev can be conveniently considered as a solution for the future engineering needs of the world. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Journal overview. Special Issues. Academic Editor: Run-Cang Sun. Received 05 Dec Accepted 19 Feb Published 27 Mar Abstract The name maglev is derived from magnetic levitation.

Magnetic Levitation Technology Magnetic levitation is a method by which an object is suspended in the air with no support other than magnetic fields. Electromagnetic Suspension EMS The test bed can be used as a platform for control theory and maglev work. Figure 1. Figure 2. Figure 3. Magnetic levitation system interface diagram.

Figure 4. Figure 5. Figure 6. Figure 7. A vertical peg board with stationary pegs black circles. A blue disk falls and scatters through the lattice of pegs, analagous to electrons scattering off ions as they move through a wire, leading to resistivity. Figure 8. Figure 9. Figure A schematic STM setup. For comparison, a typical light bulb usually has a flowing current of order 1 ampere. Our tunneling current is roughly 10 billion times smaller.

Engineers have a number of options to choose from as their designs progress. Photo credit: NASA. Comparison between maglev fan and traditional fan. The resulting interaction between the magnet plate and the magnet pulls the rotor downward in a full degrees. Through the lower center of gravity, the rotor runs stably in a consistent orbit. The conventional fan utilizes a deviating magnetic center to attract the rotor downwards.

This kind of technology causes the rotor to vibrate violently due to both the lack of a consistent orbit and a deviation of the magnetic center. Deficiencies of traditional motors Maglev fan solution Sleeve bearing i Weight of rotor is entirely loaded on to the shaft.

Abrasive rotation between shaft and bearing will result in an irregular and rough surface on the inner surface of bearing bore. The fan motor rotation becomes uneven and in turn causes operational noise and shortens fan life. No more traditional rubs and noise occur. Hence there is no more oil leakage or stuck rotor problems. Ball bearing i When the fan motor is operating, the steel balls inside will generate a higher rotational noise than that of a sleeve bearing.

It is easily damaged and results in louder rotational noise. Table 1. An axial-flow radial-flux permanent magnet motor with a stator iron strip segment. Permanent maglev centrifugal pump b and its impeller a , 1 motor coil; 2 passive magnetic bearing; 3 rotor magnets; 4 impeller; 5 passive magnetic bearing.

References J. Yaghoubi, N. Barazi, and M. View at: Google Scholar S. Paschall II and W. Ambike, W. Kim, and K. View at: Google Scholar W. Kim, K. Ji, and A. Yaghoubi, Magnetically Levitated Trains, Maglev , vol.

View at: Google Scholar H. Barazi, K. Kahkeshan, A. Superconducting magnets are electromagnets that are cooled to extreme temperatures during use, which dramatically increases the power of the magnetic field. The first commercially operated high-speed superconducting Maglev train opened in Shanghai in , while others are in operation in Japan and South Korea.

In the United States, a number of routes are being explored to connect cities such as Baltimore and Washington, D. In Maglev, superconducting magnets suspend a train car above a U-shaped concrete guideway. Like ordinary magnets, these magnets repel one another when matching poles face each other.

The magnets employed are superconducting, which means that when they are cooled to less than degrees Fahrenheit below zero, they can generate magnetic fields up to 10 times stronger than ordinary electromagnets, enough to suspend and propel a train.

These magnetic fields interact with simple metallic loops set into the concrete walls of the Maglev guideway. The loops are made of conductive materials, like aluminum, and when a magnetic field moves past, it creates an electric current that generates another magnetic field. Three types of loops are set into the guideway at specific intervals to do three important tasks: one creates a field that makes the train hover about 5 inches above the guideway; a second keeps the train stable horizontally.

Both loops use magnetic repulsion to keep the train car in the optimal spot; the further it gets from the center of the guideway or the closer to the bottom, the more magnetic resistance pushes it back on track. The third set of loops is a propulsion system run by alternating current power. Here, both magnetic attraction and repulsion are used to move the train car along the guideway. Imagine the box with four magnets -- one on each corner.