Once, I played with a magnet at home, and I put it next to the compass. Suddenly, the pointer pointed to the magnet, and the pointer pointed to the place where the magnet moved. I thought it was fun, so I came up with an interesting way to play-drawing with magnetism. I first tie the refill of the movable pencil to the pointer of the compass, put a piece of white paper under it, and then turn the pointer with a magnet. Where the magnet is attracted, the refill is scratched. I saw a line similar to ECG on the paper, and my eyes lit up.
Suddenly, a goose-shaped magnet rolled past the compass and was facing my magnet. At this moment, I saw the pointer jump up like a spring. I thought I was dizzy, so I opened the lid to see what was going on. The result is still the same. The pointer was attracted by two magnets. Seeing this phenomenon, I am puzzled. I ran to tell my father at once. "Dad, dad, I found the magnetic levitation! Look! " Dad looked at my device, laughing and crying: "You call this magnetic levitation? I think this is clearly two magnets attracting each other! The real magnetic levitation is not that different poles attract each other, but that the same poles repel each other, because the huge repulsion can' hold' the heavy train instead of attracting it firmly, so it will not move. "
I asked again, "How will the train move after it floats?" "Of course, it depends on the power of the train, but because it floats in the air with little resistance, it is still quite fast." I still don't give up. I look up the principle of "maglev train" on the Internet. It turns out that dad was wrong, too. In fact, there are magnets on trains and tracks. Repulsion can make the train float or "push" the train forward. Moreover, the front track also uses gravity to "pull" the train.
Oh, I see! Disappointed, I packed up my "beaten army" and went back to study. But I am very happy, because sometimes, my mistakes can also bring me a lot of knowledge.
On Wednesday, we went to Pudong International Airport to take the maglev train, which is the fastest means of transportation on land.
We first came to the "principle area of maglev train". It turns out that the manufacture of maglev train is based on the principle that magnets repel each other.
Its track is actually a huge magnet, and there is also a magnet at the bottom of the train, which makes the magnet defying gravity. Make the train completely off the track and run in suspension.
Then, we came to the entrance of the maglev station. There are many people here. In addition to our third grade, there are many foreigners coming to take the bus. They may want to feel the high speed of maglev train. When you enter the carriage, you are greeted by chairs with cushions on both sides.
There is a red carpet for people to walk in the middle, and the words "welcome to take the maglev train" are displayed on the electronic display screen above the two ends of the carriage. How international all this is! After a while, the subtitles disappeared and the train began to move slowly.
The electronic display began to show 1 km, 2 km ... The scenery on both sides slowly passed by, and at 60 km, the speed was almost the same as that of a car. 100 km can only enjoy the scenery for a few seconds, it is as fast as an arrow at 200 km, and almost as fast as an F 1 racing car at 300 km, 4365438+. Just when my heart was surging, the train had arrived, and I was still unfinished.
Because the distance from Pudong International Airport to Longyang Road is 16.2 km, and we only need 7 minutes and 30 seconds. It's incredible! Then, we visited Pudong International Airport ... I was deeply impressed by the experience of taking the maglev train.
3. Writing a popular science essay (800 words) on the topic "How much do you know about magnetic levitation" is a technological invention in the 20th century, and its principle is not profound. It uses the property of "like-sex repulsion and opposite-sex attraction" to make the magnet have the ability of defying gravity, that is, "magnetic levitation". Scientists apply the principle of "magnetic levitation" to the railway transportation system, which makes the train completely off the track and float, becoming a "wheelless" train with a speed of more than hundreds of kilometers per hour. This is the so-called "maglev train".
Because magnets have two forms: like repulsion and opposite attraction, there are two corresponding forms of maglev train: one is a maglev train with electromagnetic operation system designed by using the principle of like repulsion of magnets, and the car body is suspended by using the repulsion between the magnetic field formed by superconducting electromagnets on the car and the magnetic field formed by coils on the track; The other is a maglev train with an electric operation system designed by using the principle of opposites attracting magnets. Magnets are installed at the bottom and upside-down tops of the car body, and induction plates and induction steel plates are respectively installed above the T-shaped guide rail and below the leg part to control the current of the electromagnet, so that a gap of10 mm (2mm) is maintained between the electromagnet and the guide rail, and the attraction of the guide rail steel plate is balanced with the gravity of the car, so that the car body is suspended on the guide rail surface of the lane.
Maglev train is the product of modern high-tech development. Its principle is to use electromagnetic force to counteract the gravity of the earth, and make the train suspend on the track by linear motor (suspension gap is about 1 cm). Its research and manufacture involve automatic control, power electronics technology, linear propulsion technology, mechanical design and manufacture, fault monitoring and diagnosis and many other disciplines. Technology is very complex, which is an important symbol of a country's scientific and technological strength and industrial level. Compared with ordinary wheel-rail trains, it has the characteristics of low noise, no pollution, safety and comfort, high speed and high efficiency, and has the reputation of "zero-altitude aircraft". It is a new type of transportation with broad prospects, especially suitable for urban rail transit. Maglev trains are generally divided into repulsion type and suction type according to the different suspension modes, and there are high speed and medium-low speed according to the running speed.
"If you leave" is the basic working state of maglev train. The maglev train uses electromagnetic force to counteract the gravity of the earth and make the train suspend on the track. During the operation, the car body and the track are in a state of "at arm's length", and the magnetic levitation gap is about 1 cm, so it has the reputation of "zero altitude aircraft". Compared with ordinary wheel-rail trains, it has the characteristics of low noise, low energy consumption, no pollution, safety and comfort, high speed and high efficiency, and is considered as a new type of transportation with broad prospects. Especially this kind of medium and low speed maglev train has small turning radius and strong climbing ability, which is especially suitable for urban rail transit.
4. First Person Introduction of Maglev Train In the first spring of the 20th century, the first shovel of the world's first commercial maglev train line was dug up in Pudong, China. With the opening of the maglev train, I've always wanted to see it myself.
This year's National Day witnessed the heroic attitude of Shanghai maglev train. That day, my father drove us to visit Pudong Airport. Driving to Longyang Road, from a distance, a huge steel dome building stands at Longyang Road Station of Shanghai Metro Line 2. Dad told me that this is the starting point of the high-speed maglev train. After careful observation, I saw that the newly built magnetic levitation Longyang Road stood dazzling in the early morning sun, which was very modern. Ah, this is the starting point of the maglev train.
Just then, a train left the station. The newly started train is not fast. I can see clearly that the train is dominated by white, and the blue and red carriages are charming. The streamlined body appearance, bullet-shaped front and artist's painted appearance show a unique posture. The train goes faster and faster, and then flies on the track at lightning speed, just like a little white dragon flying over the city. In the blink of an eye, the train in the distance has turned into a small white spot and soon disappeared without a trace. "God, so soon!" I can't help but be surprised at the high speed of the maglev train. When I lost my mind, I remembered reading that the high-speed maglev train is a new type of rail transit, which has the advantages of high speed, strong climbing ability, low energy consumption, low noise during operation, safety and comfort, no oil consumption and less pollution. It does not use mechanical force, but mainly relies on electromagnetic force to make the car body float off the track, just like an ultra-low altitude plane running close to a special track. The whole operation process is to achieve non-contact and friction-free high-speed driving, with a speed of 550 kilometers per hour, so it has the reputation of "ground plane" and "ultra-low-altitude plane". Today, I really understand why the maglev train is called an ultra-low altitude plane. I can't help feeling that scientific progress is so fast that it has brought us such convenient, fast and environmentally friendly means of transportation. How clever humans are! As I thought about it, I kept looking back at the maglev train station that was getting farther and farther away.
Seeing my reluctance, my mother interrupted my meditation and introduced me: "Shanghai maglev train starts from the south side of Longyang Road Station of Shanghai Metro Line 2 in the west and ends at the east side of Terminal 1 of Pudong International Airport in the east. The total length of the line is 3 1. 17km, and the design speed and running speed are 505 km and 430 km respectively, with a total investment of 8.9 billion yuan. The upper maglev train is listed as three carriages, with about 200 seats * * * ... "
I am very excited to hear these values. I think: the face of the city is really displayed by riding a flight of stairs on a maglev train!
5. Talk about 400-word hot topic composition. We will have fantasies and interests about the magnetic effect of maglev train on space, among which maglev train also has a mysterious and curious veil in people's lives.
Now all primary and secondary school textbooks will learn the principle of magnets, that is, opposites attract and the same sex attracts. Maglev railway technology applies this principle, together with the operation and feedback control principle of power electronics, to drive the train to float on the track, and the propulsion runs in the air.
Faraday's law, which is mentioned in physics textbooks of senior high school, is the interaction of electricity and force between electric field and magnetic field, and it is also the basic principle of applying buoyancy and propulsion to maglev trains. Maglev trains use electromagnetic attraction and propulsion to suspend the trains at a height of about 0.9 cm to 10cm above the track, among which German and Japanese maglev trains are the most famous and mature, and South Korea and China have also formed light rail.
German high-speed maglev train has been officially put into operation at Shanghai Pudong Airport. It can be suspended at rest by using the magnetic force of electromagnet. The maximum speed of the train is 430 kilometers per hour. Japan's high-speed maglev train uses superconductors to suspend the train when it accelerates to 60-70 kilometers per hour. The maximum speed of the train has reached 58 1 km in the trial operation of passenger transport in June 2003. In addition, in March 2005, the maglev rapid transit system was officially put into operation in the hilly line of eastern Japan, with a total length of 8.9 kilometers. The train speed of this system is 100 km. The system belongs to the metro type, which is statically suspended at the station, and has the characteristics of small turning radius, fast lifting and short station distance.
Maglev train has been put into research and development in Germany and Japan for 40 years. Because of the advantages and disadvantages of maglev track construction, there are experts in all countries, especially during the trial operation of Shanghai maglev train, many engineering and technical problems have appeared. From the perspective of engineering technology, any problem can be solved, which is the engineering treatment method. However, the high-speed maglev system is an intercity means of transportation, which does not have the traffic characteristics of subway rapid transit. The consideration of transfer system is very important, which is the main reason for the poor operation of Shanghai high-speed maglev.
Of course, maglev railway also has many advantages, such as vibration reduction, noise reduction, speed increase and environmental protection. As long as the reliability and stability of the system are improved and affirmed, it is believed that it will bring a faster and more comfortable mass transportation system, which is also the blessing of mankind in the world.
On the weekend, my parents promised to take me to Pudong International Airport, just in time to experience the magnetic levitation. I put my small schoolbag on my back and put my favorite snacks and drinks on it. The boss shouted "Let's go" early in the morning!
Since I'm about equal to 1.3 meters now, I hit a side ball and saved 50 yuan in fare. With a nervous and excited mood, our train started, which is much more enjoyable than taking a Lego model car at home! The train leans to the left and then to the right. In just a few minutes, the speed was increased to 300 km/h, and the opposite train roared past our train. The car on the road instantly became a beetle and crawled slowly. However, I haven't had enough addiction, and I arrived at Pudong International Airport in a blink of an eye!
Dad, why don't you ride a few more times before I pass 1.3 meters?
7. magnetic levitation summary paper I want to write a summary paper on magnetic levitation technology. It is hoped that the research of magnetic levitation technology originated in Germany. As early as 1922, Herman Kemper put forward the principle of electromagnetic levitation, and applied for the patent of maglev train in 1934.
After 1970s, with the increasing economic strength of the world's industrialized countries, Germany, Japan, the United States, Canada, France, Britain and other developed countries began to plan to develop magnetic levitation transportation systems to improve their transportation capacity and meet the needs of their economic development. According to the theory of wheel-rail limit speed at that time, the researchers thought that the limit speed that wheel-rail transportation could reach was about 350 kilometers per hour. If we want to exceed this speed, we must adopt a new transportation system that does not depend on wheels and rails.
This understanding has aroused the interest of scientific research departments in many countries, but they all give up halfway. At present, only Germany and Japan continue to study the magnetic levitation system, and both have made remarkable progress. Transrapid, a maglev train developed in Germany, reached a speed of 436 kilometers per hour on the Emsland test line in 1989.
Maglev is a maglev train developed in Japan, which set a world record of 550km/h on the test line in Yamanashi Prefecture in February 1997. After a long and repeated argument, both Germany and Japan believe that it is possible for maglev trains to be put into operation in their own countries before the middle of the next century.
What is a maglev train? The maglev train actually suspends the train in the air and is guided by electromagnetic attraction or electric repulsion, so that the train has no mechanical contact with the ground track, and then the train is driven by a linear motor. Although the maglev train still belongs to the land rail transit system and retains the characteristics of many traditional locomotives and vehicles, such as tracks, turnouts, vehicle bogies and suspension systems, there is no mechanical contact between the train and the track during traction operation, which fundamentally overcomes the problems of wheel-rail adhesion, mechanical noise and wear of traditional trains, so it may become an ideal land transportation tool that people dream of.
Types of Maglev Trains Maglev trains can be divided into two types: normal conduction type and superconducting type. Normally-guided maglev, also known as normally-guided maglev, is represented by transrapid, a German high-speed normally-guided maglev train. It uses the electromagnetic attraction principle of ordinary DC electromagnet to suspend the train, and the suspension air gap is relatively small, generally around10 mm. ..
The normal-oriented high-speed maglev train can reach 400~500 kilometers per hour, which is suitable for long-distance rapid traffic between cities. Superconducting maglev train, also called superconducting magnetic repulsion, is represented by Japanese maglev.
It uses the strong magnetic field generated by superconducting magnet to interact with the coil arranged on the ground when the train is running, and generates electric repulsion to suspend the train. The suspension air gap is large, generally around 100 mm, and the speed can reach more than 500 kilometers per hour. These two kinds of maglev trains have their own advantages and disadvantages, and their economic and technical indicators are also different. Germany tends to the former, concentrating on the development of constant conductivity high-speed maglev technology. Japan, on the other hand, is optimistic about the latter and is fully committed to high-speed superconducting magnetic levitation technology.
Germany's normally guided maglev train When the normally guided maglev train works, the electromagnetic attraction of the suspension and guiding electromagnet at the lower part of the vehicle is first adjusted to react with the windings on both sides of the ground track, so that the train is suspended. Under the action of the guiding electromagnet and the track magnet at the lower part of the vehicle, the wheel and the track keep a certain lateral distance, thus realizing the non-contact support and non-contact guidance of the wheel and the track in the horizontal and vertical directions.
The suspension gap between the vehicle and the running track is 10 mm, which is guaranteed by a high-precision electronic adjustment system. In addition, because the suspension and guidance are actually independent of the running speed of the train, the train can still enter the suspension state even when it stops.
The principle of synchronous linear motor is used to drive the normally-guided maglev train. The electromagnet coil supported on the lower part of the vehicle is equivalent to the excitation coil of the synchronous linear motor, and the three-phase moving magnetic field driving winding on the inner side of the ground track is equivalent to the armature and the long stator winding of the synchronous linear motor.
According to the working principle of the motor, when the armature coil as the stator is energized, the rotor of the motor is driven to rotate due to electromagnetic induction. Similarly, when the substations arranged along the line provide three-phase frequency modulation and amplitude modulation power to the driving windings inside the track, the bearing system and the train are pushed to do linear motion similar to the motor "rotor" due to electromagnetic induction.
Therefore, in the suspended state, the train can completely achieve non-contact traction and braking. The biggest feature of Japanese superconducting maglev train is that its superconducting elements have complete conductivity and diamagnetism at relatively low temperature.
Superconducting magnets are composed of superconducting coils made of superconducting materials. It not only has zero current resistance, but also can conduct powerful current that ordinary wires can't match. This feature makes it possible to make electromagnets with small volume and high power. The vehicle of superconducting maglev train is equipped with on-board superconducting magnets to form an induction power integration device, and the driving winding and floating guide winding of the train are installed on both sides of the ground guide rail. The induction power integration device on the vehicle consists of a power integration winding, an induction power integration superconducting magnet and a floating guide superconducting magnet.
When three-phase alternating current with the same speed and frequency is provided to the driving windings on both sides of the track, a moving electromagnetic field will be generated, thus generating electromagnetic waves on the train guide rail. At this time, the vehicle-mounted superconducting magnet on the train will receive a thrust synchronous with the moving magnetic field, and it is this thrust that pushes the train forward. It works like surfing. Surfers stand on the waves and are pushed forward by the waves.
Like surfers, superconducting maglev trains have to deal with the problem of how to accurately control the motion at the peak of moving electromagnetic waves. Therefore, a high-precision instrument is installed on the ground guide rail to detect the position of the vehicle, and the supply mode of three-phase alternating current is adjusted according to the information sent by the detector, so as to accurately control the electromagnetic wave shape and make the train run well.
The superconducting maglev train is also driven by three-phase alternating current provided by substations distributed along the line to the driving windings on both sides of the ground guide rail, and is induced by the power integrated winding below the train to realize non-contact traction and braking. However, the guide windings suspended on both sides of the ground guide rail are different from those on the outside.