INDUCTRACK MAGLEV PDF
The bearings developed at Livermore employed cylindrical magnet arrays to sta INDUCTRACK MAGLEV SYSTEM could allow trains to glide across the country. Apr 3, High reliability and lower maintenance and operating costs make magnetic levitation (maglev) technology integral to advancing the nation’s. May 9, By contrast, maglev requires complex and expensive infrastructure Called the Inductrack, the new system is passive in that it uses no.
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The Laboratory in the News. Maglev on the Development Track for Urban Transportation. THE Inductrack magnetic levitation maglev system, conceived by Livermore physicist Richard Post as a safer, cheaper, and simpler means to levitate urban and high-speed trains, is moving down the development track on the way to a full-scale demonstration.
Using unique configurations of powerful, permanent magnets, called Halbach arrays, to create its levitating fields, Inductrack is under development by General Atomics GA in San Diego.
The project is sponsored by the federal government to showcase a new generation of urban transportation technology. Inductrack was conceived by Post in the mids as a new type of maglev technology, one that would use Halbach arrays located on the underside of induxtrack cars.
The magnetic fields generated by these arrays interact with a track composed of shorted circuits to create levitating and centering magnetic forces. The system is fail-safe upon loss of power, and simpler and lower in cost than current maglev systems. The Inductrack concept for mass transportation was first demonstrated at Livermore in with a subscale model using a kilogram levitated test cart and a meter-long track.
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The tests were so successful that inducrack National Aeronautics and Space Administration NASA awarded the Laboratory a contract to study the technology as a means to help launch rockets into space. The rockets would be sent up an inclined slope to about Mach 0. The Inductrack will be set up and tested by engineering graduate students at the Florida Space Institute, which is a technical training institution for NASA.
GA concluded that Inductrack was the levitation approach that best met its needs, based on factors such as simplicity, inductraack, capital and maintenance costs, and design flexibility.
Sam Gurol, General Atomics program manager, notes that GA has worked with Livermore scientists, including Post, for years on a variety of research projects, most of them related to magnetic fusion. Studies at GA, Livermore, and other institutions have shown that a maglev system using Inductrack offers many benefits, including its ability to operate in all weather conditions and in terrain with steep grades and tight turns, its low maintenance, and its rapid acceleration. Also, its quiet operation allows elevated tracks to run through neighborhoods, thereby eliminating the need to tunnel underground for noise abatement.
For many urban environments, the maglev system can result in significant cost savings over conventional transportation systems. Full-Scale Test Track under Construction In MayGA broke ground at its San Diego facility on a meter-long, full-scale test track, which will feature both straight and curved meter maglec sections.
In June, a test vehicle consisting of a single, full-scale chassis unit a mass transit vehicle has two chassis units was shipped to GA from Hall Industries in Pennsylvania.
The vehicle chassis is composed of upper and lower Halbach arrays, additional Halbach magnet arrays for the propulsion system, auxiliary wheels, and secondary suspension components.
S&TR | November Maglev on the Development Track for Urban Transportation
The initial tests will be conducted on the first 15 meters of the test track. Once the entire meter track indductrack completed, the test vehicle will be operated remotely at speeds sufficient for levitation.
Post notes that the concept of magnetically levitated trains, based on other technological approaches, has been studied in several nations for decades. Also, passengers must be shielded from the high magnetic fields generated by its superconductors.
The German maglev uses an electromagnetic design, which is based on magnetic attraction rather than repulsion and requires control systems to maintain a stable air gap of less than 10 millimeters. A breakdown of the magnet control circuits or cryogenic systems could lead to a sudden loss of levitation while the train is moving.
Dual Halbach arrays of permanent magnets are positioned under the train car to provide the levitating force. The permanent magnets also ensure fail-safe operation. If the system were to lose power, the train would remain stably levitated until it slows to walking speeds, at which point it would settle down on auxiliary wheels. Also, the use of permanent-magnet Halbach arrays allows a 2.
Such a large gap has advantages in foul weather and permits the construction of tracks with looser tolerances. Post says engineers rejected using permanent magnets for maglev systems decades ago because the lifting forces developed by the magnets were not powerful enough relative to their weight.
That situation was changed by two developments. First, the theoretical analyses in the s conducted by physicist Klaus Halbach of Lawrence Berkeley National Laboratory resulted in his invention of the Halbach array. Originally intended for use in particle accelerators for focusing and controlling particle beams, the Halbach array is a special configuration of permanent magnets.
Each bar is at right angles to adjacent bars so that magnetic field lines combine to produce a strong field below the array and cancel out one another above the array. Second, at about the same time as the Halbach arrays were conceived, permanent magnets made of an alloy of neodymium, iron, and boron were developed and put into large-scale production for such applications as computer hard drives.
The Inductrack: A Home-Grown Maglev System for our Nation
Inductrack features a Halbach array of permanent magnets positioned under a train car. The conductors of each rung are connected at both ends into a common bus bar, thereby forming an array of shorted circuits.
These currents produce a magnetic field that repels the array, thus levitating the train car. This repulsive force lifts the cars 2. As long as the train is moving above a few kilometers inductracl hour, a bit faster than walking speed, the car will be levitated by the motion-induced currents and their resulting magnetic field. The train will run on auxiliary wheels along rails until it reaches the transition speed, at which point it will begin levitating.
If the power suddenly fails, the train cars remain levitated while slowing down to a low speed, at which point the cars come to rest on their wheels.
Inductrack II, which is the design used by the GA urban maglev system, requires half the current to achieve the same levitation force per unit area as that required when using the single-sided Inductrack I configuration, without substantially increasing the weight or footprint area of the Halbach arrays.
Inductrack II thus has lower drag forces higher levitation efficiency at low speeds than Inductrack I, an important asset for an urban maglev system. With Inductrack, the train needs only a source of drive power to accelerate it to levitating speed, keep it powered, and provide braking. GA has selected an energy-efficient, linear synchronous motor composed of a separate Halbach array underneath the train car that interacts with motor windings embedded in the track.
Its performance can by analyzed theoretically with a high degree of confidence. The theory has been compared against subscale test results and then incorporated in simulation codes.
maglfv These codes can be used to design full-scale systems without the need for expensive and time-consuming tests and modifications as was the case for German and Japanese demonstration maglev systems. These levitation forces are close to the theoretical maximum that can be exerted by permanent magnets.
Actual values achieved in a test run at GA are about 30 metric tons per square meter, in close agreement with the theoretically predicted inductrxck force for the configuration that was tested.
While work on the demonstration effort proceeds in San Diego, the Livermore team is optimizing the design of the magnets and the track. In particular, the team is working on a novel laminated track composed of a stack of slotted sheets of copper reinforced by fiber composite.
The new design is simpler and should be lower in cost to manufacture than the litz-wire ladder track. Safer, simpler, and cheaper than other designs, Inductrack increasingly appears to be the right track to inductracj future of urban transportation systems. For further information contact Dick Post post3 llnl. Download a printer-friendly version of this article. UCRL November 7, mwglev In MayGeneral Atomics broke ground on a meter-long Inductrack test track, which will feature both straight and curved sections.
Iductrack windings are used with a linear synchronous motor to power and brake the train. This magnetic field repels the array, thus levitating the train car 2.