Magnetic Levitation - Term Paper Example

Magnetic Levitation By: + Magnetic levitation (Maglev) technology was invented by an American and a French engineer who did not have a clear sight of the practicality of its implementation back in the 1900s. This technology has been experimented over the past couple of decades with intensively. In the last ten years, scientists have developed systems that implement magnetic levitation as a reliable means of transport. Germany and Japan, as leaders in the rail system, identified the potential of magnetic levitation technology. They have implemented them in the development of reliable high-speed passenger railway transportation system. Since the development and implementation of a working system, the study of magnetic levitation technology and its application has increased as more firms around the world identify more application of the technology. Currently, JR-Maglev from Japan and TransRapid International from Germany are the two major commercial implementation of the technology. The implementation of this technology is based on the implementation of three primary functions: suspension or levitation, propulsion and guidance. This paper is aimed at reviewing the current implementation of magnetic levitation technology and it is how its implementation relates to the basics of electromagnetics. Introduction Magnetic levitation technology has been implemented in four fields according to Sadiku and Akujuobi (2006) and Park (2014), which are the novelty toys industry, the transportation industry, the manufacturing industry and the defense industry. Magnetic levitation has been implemented in the novelty toy industry based on the ease and cheapness of acquiring magnets for use in small toys. Such toys include magnetically levitated globes as shown in figure 1. Figure 1: Magnetically Levitating Globes Magnetically levitating globes can be found in offices and are quite impressive although they just implement basic electromagnetic principles. According to Elreesh and Hamed (2012), the globes uses magnetic field sensors that permanently measure the height each globe is to be suspended which then transmits the data to a microcomputer located in the base unit. To keep the globes correctly levitated, the computer calibrates the electronic magnets located at the top of the frame. Other toys such as the Tasmanian devil implementation by Wendy’s fast food store chains applies the same electromagnetic principles. According to Ueno and Higuchi (2004), the implementation of such toys is based on the use of regulated electro-magnets and a computer that ensures that the height of the suspended object remains intact offering an illusion of defying gravity by levitating the objects. In the transport industry, companies such as JR-Maglev from Japan and TransRapid International from Germany have implemented magnetic levitation technology in the development of high-speed trains. The implementation relies of electromagnetics to offer a non-adhesive drive system that is free from wheel-rail frictional forces hence increasing the speed of the system by elimination of friction with the exception of aerodynamic drag. Their implementation has however been criticized by authors and researcher such as Takao et al., (2010), Takao et al., (2014), and [critisizer3] who argue that based on their cost of implementation and maintenance, the mechanical and electronic complexity, and stability of their operations the practicality of fully and global implementation of such systems is impractical. Based on how the transport systems are implemented Takao et al., (2010) and [critisizer3] argue that the practicability of high-speed tracks being implemented globally and commercially faces great drawbacks in terms of cryogenic cooling systems and complicated feedback circuits that are required to overcome the instabilities that superconducting coils have. However, scientists continue to develop these systems based on their economic and social benefits to the society. Ueno and Higuchi (2004) argues that the implementation of magnetically levitated transport systems are beneficial in that they are reliable, require minimum maintenance, have low energy consumption and they pose low environmental impacts since they pose negligible air and noise pollution a claim that is supported by both Sadiku and Akujuobi (2006) and Elreesh and Hamed (2012). The magnetic levitation transport systems rely on electromagnetic principles are described by their functionality and engineering. The trains require a guide way, which acts as a rail track on conventional railway line. The guide way applied electromagnetic forces between coils on the ground and superconducting magnets located on the trains as shown in diagram 1. Diagram 1. Principle of Magnetic Levitation. The diagram shows levitation coils installed on a guide way’s sidewalls and the corresponding superconducting magnets, which come attached to the train. The guide way functions such that as the train is moving at a high speed rate, an electric current passes through the coils at that instant when the train is passing over the coils thus the coil turns into an electromagnet temporarily. As the coils are turned into electromagnets, the interaction between the magnets on the train and the coils on the guide way produces a suspension /levitation effect on the train allowing the train to levitate above the guide way for a few inches until it reaches another coil on the guide way producing the same effect repeatedly. The mechanically levitated train system also applies the principle of lateral guidance to prevent issues with the train moving /sliding from side to side as the electromagnetic forces produced also contain unstable forces as shown in diagram 2. Diagram 2. Principle of Lateral Guidance. In this implementation, the levitation coils are placed on the sidewalls facing each other under the guide way. These coils are charged to produce the same pole which alternate as the train goes down the guide way. As the train is in motion atop the coils, an electric current is sent to trigger an electromagnetic effect on the coils creating an electromagnetic force, which reacts with the forces emitted by the magnets on the train. As the train is in motion, and the current is active, a repulsive force is applied on the coils on the side nearest to the train while an attractive force acts on the coils located further away from the train. This acts to balance the train as it moves over the guide way since when it is attracted to a way it then repelled from the wall after it travels for some distance resulting in a balanced state where the attraction and repulsion rates of both sides are equal and opposite. By engineering the principle of lateral guidance according to Ueno and Higuchi (2004) a state of equilibrium is achieved since the current is passed at on coil at a time ensuring that the train remains at the center of the guide way throughout its motion. The magnetically levitated transport system applies the principle of propulsion hence ensuring effective transportation without the need to use a propellant. Aside from the coils in the used in balancing the train, there are other coils that alternate between the south and north poles which are only active as the train is passing by. According to Park (2014) and Ueno and Higuchi (2004), the process acts as a money saver in that the magnets are only active as the train passes by thus saving power. Higuchi (1991) and Elreesh and Hamed (2012) give a different for the implementation of the magnets as such. They argue that if the magnets where to be left running throughout, the resultant force acting on the train would be unnecessary, overwhelming and could result to unpredictable occurrences as the train passes through the guide way. On the train’s sides, superconducting magnets of unlike kinds are positioned as shown in diagram 3. Diagram 3. Principle of Propulsion. The coils used in the propulsion of the train located on the side wall are powers by a strong three-phase AC current hence creating a strong shifting magnetic field on the guide way. This causes the on-board superconducting magnets to be repelled and attracted by the shifting magnetic field thus providing the push required to start and maintain the motion of the train. The increased force applied by the shifting magnetic field accounts for the train’s acceleration which increases exponentially resulting to high speed which can be controlled by regulating the current being sent through the coils or by completely switching off the current of the coils. This type of magnetic levitation technology has already been successfully implemented in Japan. Figure 2. Japanese Guide ways The third implementation of magnetic levitation is in the manufacturing industries where it is part of the manufacturing process in industries such as the steel industry. The magnetic levitation technology can be implemented in the manufacturing industry through components known as floaters e.g. Figure 3. Figure 3. Floaters in the Steel Industry These floaters are used to separate and continually count processed sheets of steel or iron. According to Nakagawa and Hama (2000), the adaptation of floaters in the steel industry was due to the errors that the production process constantly produced and hence the need to identify and count the number of good processed sheets. Sadiku and Akujuobi (2006) and Nakagawa and Hama (2000) explain that the technique floaters use requires minimum or no human intervention with the steel sheets since they are levitated atop each other. Since there is no human or mechanical contact with the elevated sheets, their production is increasingly efficient and time saving. The floaters do not require steel sheets to be separated or cleaned before being counted thus oily, painted and clean steel sheets can be processed without waiting for them to dry or cleaning them or ensuring that the clean sheets remain clean. Floaters use mutual magnetic repulsion to separate stack of steel sheets ensuring that no sheet is in contact with the other. This according to Nakagawa and Hama (2000) adds an advantage in that they eliminate cases of scratching, bending, prying of marring costly material and protecting the steel sheets from destroying expensive dies, shears, forming or punching the equipment. Floaters are designed with two electromagnets at each end, which are activated independently. The sheets are placed with one end laying on one electromagnet, which is then activated consequently magnetizing the steel sheets on top with similar polarity through induction. Due to this, the top two or three steel sheets repel each other and float in the air. Rail guns are other applications of magnetic levitation technology, under the principle of propulsion, where an object is propelled at high velocity between two rails.   Diagram 4. Rail Gun Design Diagram 4 shows the design of a simple rail gun where a two conducting rails are placed parallel to each other at a distance L. one rail it connected to the negative terminal of a power source while the other to the positive terminal. Once a connection is established there is a potential current I due to the voltage V from the power source. A good electricity conductor is placed between the two rails thus completing the circuit and thus current, I, begins to flow through the rails creating a magnetic field in the direction of the opening. Based on the right hand rule, the object is propelled toward the opening rather than toward the power source as shown in Diagram 5. Diagram 5: Impact of Magnetic Field on the Projectile Based on the principle of propulsion, research institution such as Sandia National Research Laboratories and Maxwell Laboratories have developed rail guns that have achieved impressive velocities. An experiment by Sandia National Research Laboratories achieved a velocity of 16000m/s after the fired a 0.1 gram object through a 6mm hypervelocity launcher while Maxwell Laboratories achieved a velocity of 3300m/s from a projectile weighing in at 1.6 kilograms. Through their experiments, the kinetic energy discovered to be produced from each experiment was about nine Mega joules, which is capable of propelling objects at greater speeds compared to conventional chemical. Through these achievements, the US government and NASA have realized the possibility of implementing rail guns in the defense industry. NASA has been actively funding the research and development of stronger rail guns with the possibility of creating a high velocity launcher for their space shuttles, which would be economical comparing the amount of fuel used in one single launch. This would increase the number of rockets they send into outer space incredibly thus increasing the research speed they continue to conduct concerning outer space. The US government according to Wai and Lee (2008) has had several experiments regarding the use of rail guns as alternative defense weapons. The implementation of magnetic levitation technology in defense will have an increased effect on the cost of production of weapons in that the cost would be cut significantly based on the use of electromagnetic current as the propellant other than gunpowder. Other studies are currently under process that consider the utilization of rail guns in Fusion Fuel Pellet Injectors for their use in experimental nuclear fusion reactors and in the area of metallurgical bonding. Studied continuing at the University of Texas in Austin Texas, United States, have established that by use of rail guns the process of Electromagnetic Powder Deposition is capable of accomplishing a depot material coating with the strength of the bond that is similar to the material making up the base with a porosity of below 3%. Electromagnetic Powder Deposition refers to the use of rail guns to propel a mixture of finely ground powder at an object where the object is coated with the powder very tightly since, it reaches the object at incredibly high speeds thus the tight compartment. The experiments in the University of Texas are aimed at developing repair techniques that can be used in the repair of components of the jet engine. Similar projects are being carried out in other research institutions where the researcher are trying to create new elements by creating high shock pressures when colliding two elements through magnetic levitation technology (rail guns). In conclusion, magnetic levitation has a lot to offer in terms of economic development, time saving, and environmental conservation as the cost of implementing and maintenance of systems applying this technology is cheap thus should be encouraged and promoted. The development of new applications of magnetic levitation needs to be upheld and promoted by research institutions as their practicability is beyond doubt. Although critics exist that, hinder the use of magnetic levitation the capability that this technology holds is yet to be harnessed and witnessed. In the implementation of magnetic levitation technology, globalization, research, defense and other fields will grow incredibly, as the transportation between two geographically distant places with be enhanced and research scopes will be enlarged. Reference list Elreesh, H. and Hamed, B. (2012). FPGA Fuzzy Controller Design for Magnetic Ball Levitation. IJISA, 4(10), pp.72-81. HIGUCHI, T. (1991). Applications of Magnetic Levitation and Magnetic Bearings in Robotics. Journal of the Robotics Society of Japan, 9(4), pp.474-478. Nakagawa, T. and Hama, M. (2000). Study of Magnetic Levitation Control by Means of Correcting Gap Length Command for a Thin Steel Plate. IEEJ Transactions on Industry Applications, 120(4), pp.489-494. Park, Y. (2014). Design and implementation of an electromagnetic levitation system for active magnetic bearing wheels. IET Control Theory & Applications, 8(2), pp.139-148. Sadiku, M. and Akujuobi, C. (2006). Magnetic levitation. IEEE Potentials, 25(2), pp.41-42. Takao, T., Saito, S., Doi, T., Kameyama, S. and Kamijo, H. (2010). Increased Levitation Force in Magnetic Levitation System Using Magnetic Shielding Effect of HTS Bulk. IEEE Trans. Appl. Supercond., 20(3), pp.884-887. Takao, T., Horie, T., Usami, T., Takahashi, M. and Kamijo, H. (2014). Levitation Property of Parallel Magnetic Levitation System With Magnetic Shielding Effect of HTS Bulks. IEEE Trans. Appl. Supercond., 24(3), pp.1-4. Ueno, T. and Higuchi, T. (2004). Zero-power Magnetic Levitation using Magnetic Force Control Device of Lamination of Magnetostrictive Material and Piezoelectric Material. IEEJ Transactions on Industry Applications, 124(7), pp.724-729. Wai, R. and Lee, J. (2008). Backstepping-based levitation control design for linear magnetic levitation rail system. IET Control Theory & Applications, 2(1), pp.72-86. Read More