Electromagnetic Propulsion

Electromagnetic Propulsion : The Future of Transportation

We can reach unseen distances in space, even at a more feasible and simple way.

Image: nos.nl

The principle of accelerating an object by the flowing electrical current and magnetic fields is known as Electromagnetic propulsion. In this electrical currents are used to create an opposing magnetic field to repel, or to charge a field, which can then be repelled.

When a current is flown through a conductor placed in a magnetic field, an electromagnetic force (referred as a Lorentz force) is generated which pushes the conductor in the direction which is perpendicular to both the conductor as well as the magnetic field. This is how electromagnetic propulsion is achieved with help of repulsion of magnetic fields.

The origin of this phenomenon is not associated with a particular individual. The thought of using magnets for propulsion dates back to 1897 when an author named John Munro published his fictional story "A Trip to Venus", now so many decades later this technology is being used is spacecrafts, as well as in trains, lifts, military rail-guns and some applications are still under development.

One of the first recorded discoveries for electromagnetic propulsion was made by Professor Elihu Thomson in 1889 when he made his work public, He had researched on electromagnetic waves and alternating currents. Some years later in the early 1890s Emile Bachelet proposed an idea of a metal cart levitated above the rails in a modern railway and also showcased a model.  The first practical application of electromagnetic propulsion was introduced by Eric Roberts Laithwaite In the 1960s when he developed the linear induction motor, which built upon these principles . James R. Powell and Gordon Danby filed a patent for superconducting maglev transportation system In 1966, after which engineers around the world raced to create the first high-speed rail. First commercial automated maglev system was built  in Birmingham around 1984 -1995.It was a low speed Maglev train.

Image: CRRC

Maglev Train

Maglev stands for magnetic levitatiion. Electromagnetic propulsion is utilized in trains to minimize friction due to which high speeds can be achieved. Generally used in trains with a linear induction motor to power trains by magnetic currents. It is also used in theme parks to create high-speed roller coasters. Mainly there are two processes for transportation of maglev train,

Magnetic Levitation

courtesy: Energy.gov

In the figure you can see how the train is levitated with help of pairs of magnets, with one set attached to the train car while other on the rail track, with both of them having same pole facing each other because of which there is repulsion between track and car which creats levitation. The levitated train faces no friction due to tracks, only fluid friction is faced by the train.

Magnetic Propulsion

In this figure you can see how the levitated train is propagated on the track. There is a strip of magnets running along side the track of the train, with alternate poles of magnet, also the train car has alternate magnet poles on it. Due to constant attraction and repulsion between alike and like poles on train car and the strip running along there is propulsion of train.

Courtesy: Energy.gov

Photo: How things work

The train can achieve speeds up to 500 km/h (310 mph). If some hoe fluid resistance can also be eliminated the the trains can achieve even higher speeds. This explanation is give on basis of permanent magnets instead of this electromagnets can be used to make the journey more safe and also this train requires no drivers as everything can be controlled by codes to change the polarity of electromagnets so the human error is also eliminated therefore the danger of accidents is eliminated.

A different way of electromagnetic propulsion which is used in many equipments as as shown :-

fig1

fig2

In fig 1 we can see two magnets placed on a cart with same poles facing each other, both poles repel each other, but as the electromagnetic (repelling) wave travels from magnet A to B, before it reaches magnet B the polarity of magnet B is inverted (in fig 2) so now opposite poles face each other, there is attraction between the two magnets, so magnet B sends electromagnetic (attractive) wave towards magnet A but as it is about to reach magnet A, polarity of magnet A is reversed and now again both North pole face each other there is repelling force between them, this repeating changing magnetic field makes the cart to move forward as the two ends are pushed(repelled) and pulled(attracted) towards each other.

fig3

fig4

This technique is used in propulsion of spacecrafts and submarines in water. It is also said that using this technique we can reach distances in space never seen before, scientists are working in this direction.

For several decades chemical propulsion has been used for transportation, we have been using diesel trains then diesel cars, mopeds, etc. which is responsible for polluting the environment. Now electric transportation has began its evolution, earlier we only used electric trains but now we see many companies launching new electronic cars, mopeds, etc. The future is near when electromagnetic propulsion will be used in our daily transportation.

Courtesy: Docplayer.net

Now we already use electromagnetic propulsion in trains like maglev train, monorails etc. As maglev trains had only one issue which was holding it back from achieving highest speeds that was fluid

friction, now companies like SpaceX are working on a technique called hyperloop in this the maglev train is used in a vacuum sealed tubes which eliminates fluid friction, let the train achieve highest speeds a human body can withstand, Every example in history suggests every propulsion technique that exceeded was first used for train, now if SpaceX exceeds in hyperloop, electromagnetic propulsion will take over transportation, electromagnetic propulsion has least disadvantages as it has no/less pollution, is safe as human error is eliminated and it is also feasible as compared to other techniques, let us see what future brings in for electromagnetic propulsion or some unknown propulsion.

References:

1. Fiyaz Ahmad,":Magnetic Levitation (Mag Lev) Trains",'How things work', 06 Sep, 2009

2. Jon Poter, "China unveils prototype maglev train with max speed of 373 mph", May 24, 2019

3. Chelsea Whyte,"How Maglev works", Energy.gov, June 14, 2016

4. Spacex, "Hyperloop Alpha", SpaceX, August 12,2013