Maglev info to share cntd from my blog article from the web


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Hi guys,

Some of you who were 'MAGLEV CRAZY' like me have stopped talking about the technology lately. I cannot let die my passion for it!! So, here we go.. A continuation from my blog.. An article which I read on the web which helped me create my prototype of it. You can also log on to youtube to see how maglev prototypes are made. Would cost you anything around 5 ks to build a small. All you require is electromagnets. Make sure you are safe during the experiment and do not touch the electromagnets when active!!



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Maglev info to share cntd from my blog article from the web

  1. 1. Maglev CNTD..The second of the two main types of suspension systems in use is theelectrodynamicsuspension (EDS). EDS uses superconducting magnets(SCM) located on the bottom of the train tolevitate it off of the track.By using super cooled superconducting magnets, theelectrical resistance insuperconductors allows current to flow betterand creates a greater magnetic field. The downside tousing an EDSsystem is that it requires the scms to be at very cold temperatures,usually around 5 K(-268ºc) to get the best results and the least resistancein the coils. The Japanese Maglev, which isbased on an EDS system,uses a cooling system of liquid nitrogen and helium.To understand what’s really going on here, let’s start from theinside out. The first majorDifference between EDS and EMS is the type of track. Whereas withEMS the bottom of the train hooksaround the edges of the track, an EDStrain literally floats on air, as shown in the figure [6].FIGURE [6]
  3. 3. Systemthe outside guides act like the cushions used to prevent gutterballs in bowling only an edstrain has a magnetic safety net to keep thetrain centered, unlike your traditional bowling ally. If thetrain is knocked inthe horizontal direction, the field on the side it shifts to becomes greaterand thefield on the opposite side weakens due to this increase indistance. Therefore, in order to restoreequal magnetic forces from eachside, the train is pushed back into the center of the guideway andthestrength of the magnetic fields reduces to their normal strength.This is one reason why EDS is amuch more stable suspensionsystem. A second reason why the Electrodynamic Suspension systemismore stable is that it is able to carry a much heavier weight loadwithout having its levitation greatlyaffected. As the gap betweenthe train and vehicle decreases, forces between the scms locatedon thetrain and the magnets on the track repel each other and increaseas the train gets heavier. Forexample, if weight is added to the train, it isgoing to want to get closer to the track; however itcannot do so becauserepulsion forces grow stronger as the poles on the train sink closer tothesimilar poles on the guideway. The repulsive forces between themagnets and coils lift the train, onaverage, about 4 to 6 inches abovethe track, which virtually eliminates any safety issues regardingthetrain losing levitation and hitting its guideway. This brings us to the nextthing we encounter aswe move out from the center of the guideway.Levitation coils repel the scms underneath the train,providing the restoringforces to keep the train aligned.Propulsion coils are located next. Thepropulsion system of the Electrodynamic Suspensionsystem is quitesimilar to Electromagnetic propulsion, but does vary slightly. To propel thetrain, theguideway has coils running along the top and bottom of thescms. Induced current within these coilscreates alternating magneticfields that attract or repel the scms, sending the train in the forward
  4. 4. orreverse direction. Because the trains are moving by magnetic wavesthaT push and pull it forward, it’svirtually impossible for trains to collidesince they are in essence “riding the same magnetic waves”.No engine or other power source is required to keep the train movingexcept the initial speedthat is required to begin levitation. Thereforewheels are required to keep the train moving until about100 km/hr (65mph) where it can then begin to levitate.Finally, the guideway has railsthat encompass the outside of the train. Within these rails arethepropulsion coils and levitation coils needed to keep the train moving andlevitating above thebottom of the track. Because the train has its ownsafety net of magnetic force to keep it centered,the rails simply provide aplace for other coils to be located and used. This railway provides noother means of support for the train since the bulk of the train is floatingabove the entire track. FIGURE[7]NEW LEADING JAPANESE EDS CAR, MLX01-901
  5. 5. EDS suspension has several positive and negative aspects to it. Tobegin, initial costs arehigh and most countries do not have the money orfeel the need to spend it on this kind of transportation. Once up andrunning however, an EDS Maglev runs only on electricity so there isnoneed for other fuels. This reduction in fuel will prove to be veryimportant to the sustainability of Maglev. One huge disadvantage of theEDS system is the great cost and inconvenience of having tokeep thesuper cooled superconductive magnets at 5K. Another drawback is thatin the event of apower failure, a Maglev train using EDS would slam ontothe track at great speeds. This is a secondreason for the wheels that areprimarily used to get the train moving quickly enough for levitation.Thewheels would need to have a shock system designed to compensate forthe weight of the car andits passengers as the train falls to the track.In Japan, where EDS Maglev is in its testing stage, trainsaverageabout 300 km/hr and have been clocked at 552 km/hr, which is a worldrecord for railspeed.Compared to Amtrak trains in the United States, which travel atan average of 130 km/hr,Maglev can get people where they need inabout half of the time. The EMS and EDS suspensionsystems are thetwo main systems in use, but there is a possibility for a third to soon jointhe pack.Engineers are constantly trying to improve on previous technology. Withinthe past few yearsthe United States has been developing a newer style ofMaglev called the Inductrack, which is similarto the EDS system. Thissystem is being developed byDr. Richard PostAt the Lawrence livermorenational Laboratory. The major differencebetween the Inductrack and the Electrodymanic System isthe use ofpermanent magnets rather than superconducting magnets.
  6. 6. This system uses an “arrangement of powerful permanent magnets,known as a Halbacharray, to create the levitating force”. TheHalbach array uSes high field alloy magnetic bars. Thesebars are arranged so themagnetic fields of the bars are at 90º angles to the bars on eitherside,which causes a high powered magnetic field below the array.TheInductrack is similar to that of the EDS system in that it uses repulsiveforces. Themagnetic field of the Halbach array on the train repels themagnetic field of the moving Halbach arrayIn the guideway. The rails in the system are slightly different. Theguideway is made from “two rowsOf tightly packedLevitation coils”. The train itself has two Halbach arrays; one above thecoils for levitation and the other for guidance. As with the EMS and EDSsystem, the Inductrack uses a linearsynchronous motor. Below is apicture of the Halbach array and a model of the Inductrack system. FIGURE [8]MODELOFTHEINDUCTRACK
  7. 7. A major benefit of this track is that even if a power failure occurs, the traincan continue tolevitate because of the use of permanent magnets. As aresult, the train is able to slow to a stopduring instances of powerfailure. In addition, the train is able to levitate without any powersourceinvolved. The only power needed for this system is for the linearsynchronous motor and “the only power loss that occurs in thissystem is from aerodynamic drag and electrical resistance in theLevitation circuits”. Although this type of track is looking to be used, ithas only been tested once on a 20-metertrack. NASA is workingtogether with the Inductrack team to build a larger test model of100 meters in length. This testing could eventually lead to a “workable
  8. 8. Maglev system for the future”. The Inductrack system could also be usedfor tHe launching of NASA’s space shuttles. The following picture displaysside by side all three types of levitation systems.FIGURE OF THREE TYPES OF LEVITATION TECHNIQUESLATERAL GUIDANCE SYSTEMSThe Lateral guidance systems control the train’s ability to actuallystay on the track. ItStabilized the movement of the train from moving left and right of the traintrack by using the systemof electromagnets found in the undercarriage ofthe maglev train. The placement of theelectromagnets in conjunction witha computer control system ensures that the train does not deviatemorethan 10mm from the actual train tracks.The lateral guidance systemused in the Japanese electrodynamic suspension system is ableTo use one “set of four superconducting magnets” to control lateralguidance from the magneticPropulsion of the null flux coils located on the guideways of the track asshown in Fig.[10]. Coils areused frequently in the design of maglev trainsbecause the magnetic fields created are perpendicularto the electriccurrent, thus making the magnetic fields stronger. The Japanese LateralGuidancesystem also uses a semi-active suspension system. Thissystem dampens the effect of the side to sidevibrations of the traincar and allows for more comfortable train rides. This stable lateralmotioncaused from the magnetic propulsion is a joint operation from theacceleration sensor, control devive,to the actual air spring that dampensthe lateral motion of the train car.
  9. 9. Systemthe lateral guidance system found in the German transrapidsystem(EMS) is similar to thejapanese model. In a combination ofattraction and repulsion, the maglev train is able to remaincentered on therailway. Once again levitation coils are used to control lateral movementin thegerman maglev suspension system. The levitation coils areconnected on both sides of the guidewayand have opposite poles. Theopposites poles of the guideway cause a repulsive force on one sideof the train while creating an attractive force on the other side of the train.The location of theelectromagnets on the Transrapid system is located ina different side of the guideways. To obtain
  10. 10. Electro magnetic suspension, the Transrapid system uses “the attractiveforces between iron-coreelectromagnetsAnd ferromagnetic rails.”In addition to guidance, these magnets also allow the trainto tilt, pitch,and roll during turns. To keep all distances regulated during theride, the magnets worktogether with sensors to keep the traincentered..ADVANTAGES AND LIMITATIONS OF maglevadvantagesmagneticFieldsIntensity of magnetic field effects of Maglev is extremely low (beloweveryday householddevices)Hair dryer, toaster, or sewing machine produce stronger magnetic fields Energy ConsumptionMaglev uses 30% less energy than a highspeed train traveling at thesame speed. (1/3 morepower for the same amount ofenergy)Speed ICE Train Maglev Train200 km/hr 32 Wh/km 32 Wh/km250 km/hr 44 Wh/km 37 Wh/km