How the maglev train moves forward

Maglev trainsThe principle of moving forward:

The principle of the maglev train is to use the property of the magnet "the same sex repels each other, and the opposite sex attracts", so that the magnet has the ability to resist gravity, that is, "magnetic levitation". This principle is applied to the railway transportation system, so that the train is completely off the track and suspended, becoming a "wheelless" train, with a speed of more than several hundred kilometers per hour. This is the so-called "maglev train".

The train is equipped with superconducting magnets, which move forward at high speed due to levitation. These coils are fixed at the bottom of the railway, due to electromagnetic induction, an electric current is generated in the first circle, and the polarity of the magnetic field generated by the ground coil is always the same as the polarity of the electromagnet on the train, so that there will always be a repulsive force between the first ring and the electromagnet, so that the train is suspended.

Advantages of maglev trains:

1. Fast speed. Maglev trains are the only ground passenger transport vehicles that can reach operating speeds of up to 500 kilometers per hour.

This means that for inter-city travel between cities with a distance of 500 km to more than 1,000 km, maglev trains are completely comparable to airplanes in terms of travel time and travel quality.

2. Low relative energy consumption. At a speed of 500 kilometers per hour, the energy consumption per seat kilometer of the maglev train is only 1 3 to 1 2 of that of an airplane, which is 3 percent less than that of a car.

3. Easy to turn, able to climb slopes, flexible line selection, and strong adaptability. The maglev high-speed line requires a much smaller turning radius than conventional railways and has a climbing capacity of up to 10. This allows the maglev line to be more flexible to adapt to the terrain, which can reduce the cost of construction.

4. Low noise. Due to the absence of friction between wheels and rails, the noise of maglev trains is lower than that of conventional railways at the same speed.

5. No pollution. Since the maglev train is powered by electricity, its development is not limited by the energy structure, especially the fuel **; At the same time, there is no exhaust gas along the track, and it is a veritable green means of transportation.

6. Safety, comfort and less maintenance. The maglev train is not easy to derail in terms of structure, and the propulsion mode ensures that it is not easy to crash. The maglev train has no contact between the wheels and the rails, the vibration is small, the comfort is good, its work belongs to the wear-free operation, the maintenance is mainly focused on electronic technology, and does not require a lot of manual labor.

The contactless suspension and guidance between the train and the track are realized by electromagnetic force, and the electromagnetic force generated by the linear motor is used to pull the train to run.

The maglev train operating in Shanghai is the world's first commercial maglev special line, connecting the urban area to the airport, reaching a speed of 430 kilometers per hour, and a distance of 30 kilometers in only 8 minutes.

The maglev train can run at high speed without an engine, and it is also the application of magnet suction and repulsion to push the train forward, after being energized, they will become a section of electromagnets with n poles and s poles, the n pole of the track magnet and the n pole of the magnet on the train will push the train forward, the next section of the track magnet n machine and the train magnet s s s attract the train to pull the train forward, and the electromagnet on the track will continue to change the magnetic pole according to the progress of the train to ensure that the maglev train continues to move forward, Magnetism can both levitate and propel the train forward.

At present, the only maglev line in the world is operated by the Shanghai Pudong Airport section. From Longyang Road Station of Shanghai Rail Transit Line 2 in the west to Shanghai Pudong International Airport in the east, you can choose Longyang Road Station or Pudong Airport Station to take it.

From Longyang Road Station to Youdohuai Station of Pudong Airport, the first train is 6:45 and the last train is 21:40;

From Pudong Airport Station to Longyang Road Station, the first bus is at 7:02 and the last bus is at 21:42.

Departure interval 6:45-17:00 15 mins, 17:00-21:40 20 mins.

Categories: Science & Engineering >> Engineering & Technology Sciences.

Analysis: The principle of maglev trains.

The principle of the maglev train is not profound. It is the use of the magnet's "same sex repels and opposite sex attracts" property to make the magnet have the ability to resist gravity, that is, "magnetic levitation". Scientists apply the principle of "magnetic levitation" to the railway transportation system, so that the train is completely off the track and suspended, becoming a "wheelless" train, with a speed of more than several hundred kilometers per hour.

This is the so-called "maglev train", also known as the "maglev car".

Because magnets have two forms of same-sex repulsion and opposite-sex attraction, there are also two corresponding forms of maglev trains: one is the magnetic levitation train jujube judgment of the electromagnetic operation system designed by using the principle of magnet same-sex repulsion, it uses the repulsion force generated between the magnetic field formed by the superconductor electromagnet buried in the car and the magnetic field formed by the track coil, so that the car body is suspended and runs the railway; The other is the maglev train designed by using the principle of magnet opposite-sex attraction, which is to install magnets at the bottom of the car body and the top of the reverse steering on both sides.

Iron, above the T-shaped guide rail and below the outrigger part are respectively provided with reaction plate and induction steel plate, control the current of the electromagnet, keep a gap of 10-15 mm between the electromagnet and the guide rail, and make the attraction of the guide rail steel plate and the gravity of the vehicle balanced, so that the car body is suspended on the guide rail surface of the lane to run.

Maglev trains have a number of incomparable advantages over today's high-speed trains:

Because the maglev train runs on the track, there is no actual contact between the guide rail and the locomotive, and it becomes a "wheelless" state, so it has almost no friction between the wheel and the rail, and the speed is as high as hundreds of kilometers per hour;

Maglev trains have high reliability, easy maintenance and low cost, and their energy consumption is only half of that of cars and a quarter of that of airplanes.

The noise is small, when the speed of the maglev train reaches more than 300 kilometers per hour, the noise is only 656 decibels, which is only equivalent to a person talking loudly, which is smaller than the sound of a car passing by;

Because it is powered by electricity, it will not emit exhaust gases along the track, and it is pollution-free, making it a veritable green means of transportation.

The maglev train is a kind of maglev high-speed train system that uses a contactless electromagnetic levitation, guidance and drive system.

The maglev train is mainly composed of three parts: the suspension system, the propulsion system and the guidance system. Suspension system: At present, the design of suspension system can be divided into two directions, namely the permeable type used in Germany and the superconducting type used in Japan.

Levitation technology is electromagnetic levitation system (EMS) and electric levitation system (EDS). Electromagnetic levitation system (EMS) is a suction levitation system, which is a combination of electromagnets on the locomotive and ferromagnetic tracks on the guide rails to attract each other to produce levitation.

When the normal conduction maglev train is working, the electromagnetic attraction of the suspension and guiding electromagnets at the lower part of the vehicle is first adjusted, and the magnet reaction with the windings on both sides of the ground track floats the train. Under the reaction of the guide electromagnet at the lower part of the vehicle and the track magnet, the wheel is kept at a certain lateral distance from the track, and the contactless support and non-contact guidance of the wheel-rail in the horizontal and vertical directions are realized.

The suspension gap between the vehicle and the track is 10 millimetres, which is ensured by a high-precision electronic adjustment system. In addition, since the suspension and guidance are practically independent of the speed of the train, the train can still enter the suspension state even when it is parked.

Knowledge points: The repulsion of the magnet with the same pole cannot stably support the car, but the superconductor can be kept stable by placing the superconductor on the magnet. This is because the magnetic field cannot pass through the superconductor, so the magnetic field lines will hold the superconductor up.

As we know, the maglev train runs on a permanent magnet, which is generally made of rare earth materials, and the magnetic field strength is within 1 Tesla.

If you put a magnet on top of another magnet, they are also mutually exclusive, and the magnet on top will float as well. But as you soon find out, the magnet placed on it is impossible to maintain a stable balance, and it will fall off at the slightest disturbance, and the secret behind this is the Earnshaw theorem's theorem）。This theorem was proposed in 1842 by an English mathematician named Ensau, who discovered:

The stable levitation of a moving object cannot be achieved entirely by permanent magnets or by the electromagnetic force between permanent magnets and soft magnets. He theoretically proved that it was impossible to achieve levitation with permanent magnets. That is to say, it is impossible to use the repulsive force between the two magnets to support the ** car, and the train will definitely overturn.

So what to do? Is magnetic levitation impossible?

Is the same true of magnetic levitation?

Something similar, of course! You can think of a magnetic field as water, if we put a superconductor in a magnetic field, it's like a hollow iron ball in water, water can't get inside the hollow iron ball, and the magnetic field can't enter the superconductor. This is the reason why the magnetic field creates buoyancy on superconductors.

The Messner effect is a macroscopic phenomenon of quantum mechanics. So, if you want to thoroughly understand the buoyancy of maglev trains, you should read a book on quantum mechanics. The 18th century was the age of the steam engine, the 19th century was the age of electricity, the 20th century was the age of IT and the Internet, and the 21st century was the age of quantum.

Therefore, the direction of the current trend of the times is quantum mechanics, and students who love physics may pay attention to the characteristics of this era.

Among the many high-tech trains, the maglev train operation is the most distinctive.

Target. Instead of clinging to the rails, it hovers over the rail surface and flies. It is not only fast, but also safe, smooth, vibration-free, and pollution-free. Maglev trains and superconducting technology are closely linked. Scientists have found that in superconductivity.

state of the substance, fully conductive and safely diamagnetic. The complete diamagnetism of the superconductor exerts an upward repulsion force on the magnet, which then floats in the air. The maglev train uses this principle to convert superconducting magnets.

It is installed at the bottom of the train, and the track is laid with continuous thin plates of good conductors. As an electric current flows through the superconductor, a magnetic field is generated, creating a downward thrust force that, when balanced by the vehicle's gravity, levitates above the track. Levitation.

The maglev train is a high-tech vehicle that uses the attraction and repulsive force between the magnetic poles. To put it simply, the repulsive force makes the train hang and the attraction makes the train move.

The train is equipped with electromagnets, and the bottom of the railway is equipped with coils. After being energized, the polarity of the magnetic field generated by the ground coil is always the same as the polarity of the electromagnet on the train, and the two are "repulsive", the repulsive force makes the train levitate, and the coils are also equipped on both sides of the track, and the alternating current makes the coil become an electromagnet. It interacts with the electromagnets on the train to make the train move forward.

The electromagnet (n pole) of the locomotive head is attracted by the electromagnet (S pole) a little earlier on the track, and at the same time is repelled by the electromagnet (n pole) a little later on the track——— one "pushes" and one "pulls".

When the maglev train is running, it maintains a certain gap (generally 1-10 cm) with the track, so it is frictionless, safe, stable and comfortable, and noiseless, and can achieve fully automatic operation.

The service life of maglev train vehicles can reach 35 years, while ordinary wheel-rail trains are only 20 to 25 years. The rail life of maglev trains is 80 years, and that of ordinary rails is 60 years.

How fast can it be?

The maglev train reached its maximum speed 39 seconds after it started, and the current top speed is 552 kilometers per hour. According to German scientists**, by 2014, the maglev train will be able to reach speeds of up to 1,000 kilometers per hour after adopting the new technology. The maximum speed of a general wheel-rail train is 300 kilometers per hour.

Shanghai's now completed maglev train line is said to have a maximum speed of 500 kilometers per hour.

Will there be electromagnetic radiation and noise pollution?

The maglev train is electrically driven and does not emit any harmful gases.