By Nick Presson
Magnetic levitation has been around for years, but with advances in technology it may become a part of everyday life. The main emphasis for magnetic levitation is for transportation. Magnetically levitated ground transportation, or “Maglev”, is an advanced mode of surface high speed transportation whereby a vehicle gliding above a guideway is suspended, guided, and propelled by magnetic forces. Can you imagine a train that that actually floats in air 4 to 6 inches in the air and travels up to 300 mph. This technology can reduce air and highway congestion, air pollution, and petroleum use.
system in the
Magnetism is a phenomenon that occurs when a moving charge exerts a force on other moving charges. The magnetic force caused by this moving charge sets up a field which in turn exerts a moving force on other moving charges. The magnetic field is found to be perpendicular to the velocity of the current.
Maglev History Timeline
1900 - Robert Goddard and Emile Bachelet conceived the concept of frictionless trains.
1930 - German scientist Hermann Kemper studied the use of magnetic fields in conjunction with airplanes and trains
1969 - American scientists James R. Powell and Gordan T. Danby patented the first design for magnetic levitational trains
1970 - Germans and Japanese start research and development towards their versions of maglev technology
1990 - U.S. Federal Government with FRA begins to support maglev technology and implements the National Maglev Imitative (NMI).
2005 - Tokyo-Osaka route scheduled to be finished
Magnetic Levitation Train, also maglev train,is a high-speed ground transportation vehicle levitated
above a track called a guideway and propelled by magnetic fields. Magnetic
levitation train technology can be used for urban travel at relatively low
speeds (less than 100 km/h, or less than 62 mph); a short-distance maglev
shuttle operated for 11 years from 1984 to 1995 between the
Types of Levitation
Two different approaches to magnetic levitation train systems have been developed. The first is called electromagnetic suspension. This is basically levitated by attraction. There are conventional electromagnets mounted at the ends of a pair of structures under the train; the structures wrap around and under either side of the guideway. The magnets attract up toward laminated iron rails in the guideway and lift the train. However, this system is inherently unstable; the distance between the electromagnets and the guideway, which is about 10 mm (3/8 in), must be continuously monitored and adjusted by computer to prevent the train from hitting the guideway.
There are 3 main components to the system that governs the functionality of Maglev Trains:
1) A large electrical power source
2) Metal coils lining a guideway or track
3) Large guidance magnets are attached to the underside of the train.
A key difference between the maglev train and a conventional train is the structure of the engine. Unlike trains in the past that used fossil fuels to pull the engine across steel tracks, the magnetic field created by the electrified coils in the guideway track walls propel the Maglev Train.
Here is a fundamental description of how Maglev operates. The guideway, which is a magnetized coil running along the track, repels the large magnets on the train's undercarriage, allowing the train to levitate above the guideway between .39 and 3.93 inches (1 to 10 cm). Subsequently, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway. To change the polarity of the magnetized coils, the electric current supplied to the coils in the guideway walls is constantly alternated. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust.
Currently, two prototypes of the Maglev Train are being
tested: one using electromagnetic suspension (
Here is a picture of how the
Japanese engineers are developing a competing version of maglev
trains that use an electrodynamic suspension (EDS) system, which is based on
the repelling force of magnets and not the attracting force. The key difference
between Japanese and German maglev trains is that the Japanese trains use
super-cooled superconducting electromagnets. These electromagnets can conduct
electricity even after the power supply has been shut off. In the
The cylindrical unit at the top, is a tank holding liquefied helium and nitrogen. The bottom unit is a SC coil alternately generating N poles and S poles. At one end of the tank is the integrally-attached on-board refrigerator, which serves to re-liquefy the helium gas once vaporized by regular heat absorption and external disturbances during running.
contact, so it may be possible in the future to run speeds in excess of 500mph. All Maglev investigated could reach speeds of 300mph.
The guideway is constructed where the vehicle wraps around a Tshaped guideway of steel or concrete beams constructed and erected to very tight tolerances, as shown in the illustrations above. The attraction by magnets and the propulsion stator packs on the underside of the guideway generates lift; attraction between a second set of vehicle magnets and the edgemounted guideway rails provides guidance.
The main advantage for Maglev is the high capacity in which it can hold. The maglev concepts that have been studied so far can deliver 12,000 passengers per hour in each direction. An equivalent air capacity would be 60 Boeing 767’s per hour in each direction at 1 minute intervals. Weather conditions is another major advantage of maglev. Conditions that would normally slow travel would not be an issue because of the noncontact propulsion and braking render make it less susceptible to the restrictions of ice, snow, and rain.
There are further advantages that stem from the fact that maglev is not dependent on petroleum. While aircraft must rely exclusively on petroleum, maglev’s electric power can be supplied from various sources. Maglev’s low energy consumption, low maintenance potential offer very low operating expenses.
Magnetic levitation of trains offers
many advantages for the public. With the
research conducted it shows that maglev is a cost-effective, environmentally
sound, alternative transportation system with significant public benefits. If the