10-04-2017, 09:30 PM
MAGNETIC LEVITATION VEHICLES
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INTRODUCTION
Magnetic levitation, or maglev, is a technology used for high-speed trains in which the vehicle
is lifted from the roadway or guideway by a magnetic field. Propulsion is by means of a
moving magnetic field. This paper discusses the development of magnetic levitation vehicles in
Germany, Japan, and the United States.
BACKGROUND
The first patent for a magnetically levitated vehicle was granted in 1968 to U.S. scientists
Gordon Danby and James Powell [1]. Funding for their project lasted only a few years, allowing
Japan and Germany to take the lead in maglev development. U.S. interest was revived in the
1980s but funding was lost around 1992. Interest in maglev transportation is again on the rise in
the U.S. as evidenced by a recent $1 billion appropriation bill. $55 million is designated for
feasibility studies in 1999. This sum will be divided among five project teams presenting the
best proposals. Based on the results of these studies, the Department of Transportation will
designate one project eligible for $950 million in funding [2].
THE GERMAN SYSTEM
In 1979, the German Ministry of Research and Technology produced the Transrapid
International TR05, the first magnetic levitation vehicle licensed to carry passengers. In 1988,
the model TR06 (see Figure 1) set a speed record of 257 mph. In 1989 a prototype commercial
service vehicle, the TR07, set a new speed record of 271 mph. The Transrapid vehicle frame
wraps around the guideway and the car is levitated by magnetic attraction to the underside of the
guideway. A closed-loop control system maintains a clearance of 3/8 from the guideway. The
power for levitation is supplied by on-board batteries charged by linear generators. Propulsion is
by syncronous linear induction using active long-stator coils mounted on the guideway, and
passive rotors on board [3, p. 2; 4, p. 87].
CONCLUSIONS
Even though three maglev train designs have been developed to commercial readiness, we have
yet to see any maglev systems in continuous commercial operation. Obstacles to commercial use
of the maglev trains include
Expense, especially in guideway construction
Existence of conventional high-speed rail systems, such as the French TGV
Health concerns regarding exposure to electromagnetic fields
Absence of a commercially successful example to reassure investors
Possibility of selecting a guideway design that will be incompatible with future systems.