What is a maglev train? Maglev train is a kind of train driven by magnetic levitation force (magnetic attraction and repulsion). So, what is a maglev train?
The train is equipped with electromagnets and the bottom of the railway is equipped with coils. After electrification, the polarity of the magnetic field generated by the ground coil is always the same as that of the electromagnet on the train, and the two are "the same polarity repels each other". Repellent force makes the train suspend, and coils are also installed on both sides of the rail. Alternating current turns the coils into electromagnets. It interacts with the electromagnet on the train to make the train move forward. The electromagnet (N pole) at the head of the train is attracted by the electromagnet (S pole) in front of the track and repelled by the electromagnet (N pole) behind the track-push and pull.
The maglev train keeps a certain gap (generally 1- 10 cm) with the track during operation, so it is friction-free, safe, stable and comfortable, without noise, and can realize full-automatic operation.
The service life of maglev train can reach 35 years, while that of ordinary wheel-rail train is only 20 to 25 years. The track life of maglev train is 80 years, and that of ordinary track is 60 years.
maglev train
How fast can the maglev train run?
The maglev train reached its maximum speed 39 seconds after its start, and the current maximum speed is 552 kilometers per hour. According to the prediction of German scientists, by 20 14 years, the speed of maglev train will reach 1000 km/h after adopting new technology. The maximum speed of ordinary wheel-rail trains is 300 kilometers per hour. It is said that the maglev train that has been built in Shanghai has a top speed of 500 kilometers per hour.
Will the maglev train have electromagnetic radiation and noise pollution?
The maglev train is driven by electricity, and there is no harmful gas emission.
Advantages and benefits of maglev train
Generally speaking, maglev train has the characteristics of high speed, low noise, environmental protection, economy and comfort.
The maglev train takes less than 4 hours from Beijing to Shanghai and 23 minutes from Hangzhou to Shanghai. When the speed reached 200 kilometers, passengers could hardly hear the sound. The maglev train is driven by electricity, and its development is not limited by the energy structure, especially the fuel supply, and it does not emit harmful gases. According to experts, the cost of maglev line is only 85% of that of ordinary track, and the longer it runs, the more obvious the benefits will be. Because the rail life of maglev train can reach 80 years, while that of ordinary rail is only 60 years. The service life of maglev train is 35 years, and that of wheel-rail train is 20 to 25 years. In addition, the annual operation and maintenance cost of maglev train is only 0.2% of the total investment of 65438+, while that of wheel-rail train is as high as 4.4%. The operation and maintenance cost of maglev high-speed train is about 1/4 of that of wheel-rail high-speed train. The passenger fare cost ratio of maglev train and wheel-rail train is about 1: 2.8.
As the fastest ground transportation, maglev train technology does have incomparable advantages over other ground transportation technologies:
First of all, it overcomes the main obstacles of traditional wheel-rail railway speed increase and has broad development prospects.
Shortcomings and shortcomings of maglev train
1. Because the maglev system relies on electromagnetic force to perform the functions of suspension, guidance and driving, once the power is cut off, serious safety accidents will happen to the maglev train, so the safety guarantee measures of maglev after the power is cut off have not been completely solved.
2. The influence of strong magnetic field on human health, ecological environment balance and the operation of electronic products still needs further study.
In 2006, a German maglev control train collided with a maintenance vehicle during its trial operation. It is reported that there were 29 people on board, 23 people died on the spot, 25 people actually died and 4 people were seriously injured. This shows that the braking ability of maglev train in emergency is not reliable, which is not as good as that of wheel-rail train. It is dangerous for vehicles on land to have no wheels. Because the train has to drop from a great momentum to a standstill, and to overcome a great inertia, it can only be overcome by the braking force of wheels and tracks. Maglev trains have no wheels. It is very dangerous to rely on sliding friction if there is a sudden power failure. In addition, the maglev train is elevated, and it is difficult to rescue at a height of 5 meters when an accident occurs. Without wheels (some maglev trains have wheels), it is difficult to drag them out of the accident site; If there is a power outage in the section, it is difficult for other vehicles and cranes to get close.
The principle of maglev train is not profound. It makes use of the properties that magnets repel each other and opposites attract each other, so that magnets 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", also known as "magnetic cushion car".
Because magnets repel each other in the same direction and attract each other in the opposite direction, there are also two corresponding maglev trains: one is a maglev train with electromagnetic operation system designed by using the principle of repulsion of magnets in the same direction, which levitates the train by using the repulsion between the magnetic field formed by superconducting electromagnets on the train and the magnetic field formed by coils on the track; The other is a maglev train with electric operation system, which is designed by using the principle that magnets attract each other. 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 of 10- 15mm 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 driveway.
Compared with today's high-speed trains, the maglev train has many incomparable advantages: because the maglev train is suspended on the track, there is no actual contact between the guide rail and the locomotive, which becomes a "wheelless" state, so there is almost no friction between the wheels and the rails, and the speed is as high as several hundred kilometers per hour; Maglev train has the advantages of high reliability, simple maintenance and low cost, and its energy consumption is only half of that of automobiles and a quarter of that of airplanes. Low noise. When the speed of maglev train reaches more than 300 kilometers per hour, the noise is only 65 decibels, which is only equivalent to a person talking loudly, which is even smaller than the sound of a car passing by; Because it is driven by electricity, it will not discharge waste gas along the track and there is no pollution. It is a veritable green means of transportation. [-(@_@)-]
19 1 1 year, a professor at Tomsk Institute of Technology in Russia designed and manufactured a maglev train model according to the principle of electromagnetic action. The model does not directly contact with the rail when driving, but uses electromagnetic repulsion to suspend the vehicle and separate it from the rail, and uses motor to drive the vehicle to move forward quickly.
1960 American scientist James? Powell and Gordon? Danby put forward the design of maglev train, which uses strong magnetic field to lift the train to a height of tens of millimeters from the track and travel at a speed of more than 300 kilometers per hour without friction with the track. Unfortunately, their designs were not taken seriously by the United States, but were preempted by Japan and Germany. German maglev trains use the principle of magnetic attraction, Klaus? 197 1 year, Ma Fei Company and MBB Company developed a permanent magnet magnetic levitation model test vehicle. Britain built a low-speed maglev railway in Birmingham in 1984 and put it into use. Its maglev train is called "Margolev" and is driven by asynchronous linear motor. The derailment surface during operation is15 mm. It consists of two carriages, each of which can carry 40 passengers. There is no driver on the train, which is automatically controlled by the computer.
The appearance of superconductivity and high temperature superconductivity has promoted the development of superconducting maglev train. This kind of superconducting maglev train levitates the car body with superconducting magnets, and obtains propulsion power by periodically changing the direction of magnetic poles. 1977 The ML500 superconducting maglev train test vehicle was built in Japan, 1979 The 7000m experimental railway line was built in Miyazaki Prefecture. At 1979, the speed reached 5 17km per hour, which proved the possibility of high-speed maglev driving. 1In March, 987, Japan completed the prototype of the superconducting maglev train, which was streamlined in shape, weighed several tons, could carry 44 people and had a top speed of 420 kilometers per hour. The electromagnetic force generated by the superconducting electromagnet equipped on the car and the electromagnetic force generated by the ground through the coil of the guide rail repel each other, so that the car body is suspended. The coils on both sides of the groove guide rail interact with the electromagnets on the trolley, generating traction to make the trolley move forward while suspending. Because it is suspended, basically no wheels are needed. However, when starting or braking, wheel auxiliary support is needed. This is similar to the need for wheels when an airplane takes off and lands. Due to the short test line, this superconducting maglev train failed to fully demonstrate its outstanding performance. China began to develop maglev trains in the 1970s, and the first small maglev prototype was floated in the spring of 1989. 1in may 1995, the first manned maglev train in China ran smoothly on the track. This maglev train is 3.36 meters long, 3 meters wide and 2 meters in gauge. It can take 20 people and has a design speed of 500 kilometers per hour. 1July, 1996, National University of Defense Technology followed the latest development of maglev train technology in the world, and successfully conducted the independent bogie module test with each electromagnet decoupled.
At present, the United States is developing an underground vacuum maglev supersonic train. This magical "planetary train" is designed with a top speed of 22,500 kilometers per hour, which is more than 20 times the speed of sound. It takes only 2 1 minute to cross the continental United States, while a jet airliner takes 5 hours. This scheme requires that firstly, a tunnel is dug underground, and two or four pipes with a diameter of12m are laid, and then the air in the pipes is pumped out to make it close to a vacuum state, and finally the maglev train is driven by superconducting.
Looking forward to the future, with the development of modern high technology, high-speed, stable, safe and pollution-free maglev trains will become the ideal means of transportation for human beings in the century.
What is a maglev train? Classification: transportation/tourism, maglev train and other means of transportation.
Problem description:
There has always been a question I don't understand, that is, why can a maglev train be suspended directly above the track without falling to both sides? Due to the influence of the earth's gravity, the objects of the maglev train in the air will always fall in the direction of least resistance (just like holding two magnets with the same magnetic poles with your hands and approaching each other, the repulsive force will distort the forward and approaching directions of your hands). And when the train turns, does the train touch the tracks? How to overcome the strong centrifugal force without contact?
Analysis:
Maglev train is a high-tech means of transportation that uses the attraction and repulsion between magnetic poles. Simply put, repulsion makes the train suspended, and gravity makes the train move.
The train is equipped with electromagnets and the bottom of the railway is equipped with coils. After electrification, the polarity of the magnetic field generated by the ground coil is always the same as that of the electromagnet on the train, and the two are "the same polarity repels each other". Repellent force makes the train suspend, and coils are also installed on both sides of the rail. Alternating current turns the coils into electromagnets. It interacts with the electromagnet on the train to make the train move forward. The electromagnet (N pole) at the head of the train is attracted by the electromagnet (S pole) in front of the track and repelled by the electromagnet (N pole) behind the track-push and pull.
The maglev train keeps a certain gap (generally 1- 10 cm) with the track during operation, so it is friction-free, safe, stable and comfortable, without noise, and can realize full-automatic operation.
The service life of maglev train can reach 35 years, while that of ordinary wheel-rail train is only 20 to 25 years. The track life of maglev train is 80 years, and that of ordinary track is 60 years.
How fast can it run?
The maglev train reached its maximum speed 39 seconds after its start, and the current maximum speed is 552 kilometers per hour. According to the prediction of German scientists, by 20 14 years, the speed of maglev train will reach 1000 km/h after adopting new technology. The maximum speed of ordinary wheel-rail trains is 300 kilometers per hour. It is said that the maglev train that has been built in Shanghai has a top speed of 500 kilometers per hour.
Will there be electromagnetic radiation and noise pollution?
The maglev train is driven by electricity, and there is no harmful gas emission.
What is a maglev train? Maglev train is a kind of train driven by magnetic levitation force. Then what is magnetic levitation force? Magnetic levitation force refers to the repulsion and attraction of magnetism. This is a technological invention of the 20th century. Germany was the first country to study this technology. 1922, German engineer Herman Johnson put forward the principle of electromagnetic levitation, and applied for the patent of maglev train in 1934.
The working principle of maglev train is to use the property of "like-sex repulsion, opposite-sex attraction" to make magnets resist gravity, so as to make the vehicle float (generally less than one centimeter), and then use magnetic force to guide and push the train forward. It can reach hundreds of kilometers per hour.
Magnets have two forms: same-sex repulsion and opposite-sex attraction, so maglev trains also have two forms:
First of all, the maglev train with electromagnetic operation system is designed according to the principle of like-sex repulsion. So where is the repulsive force formed by the train? The repulsive force between the magnetic field formed by the superconducting electromagnet on the train and the magnetic field formed by the coil on the track levitates the train. The track should cover the train, which runs in the U-shaped groove. Due to the large gap of superconducting magnetic levitation, generally around 100 mm, the train speed is relatively fast, generally above 500 km. This technology is complex and has low security. Japan is this form of application.
Secondly, according to the principle of opposites attract, a maglev train with electric operation system is designed. So where is the magnet installed, and where is the attraction of opposites? First of all, this track is a T-shaped platform, and the lower parts on both sides of the train should cover both sides of the T-shaped track. The traditional electromagnet is installed at the bottom of the car body and levitates by the attraction between the electromagnet and the magnetic track above. The gap between the electromagnet and the guide rail is about 8~ 10 mm, which balances the attraction between the guide rail steel plate and the gravity of the vehicle and finally levitates the train. This technology is simple and safe, but because of the small suspension gap, the speed of the suspended train can only reach between 400 and 500 kilometers per hour. Germany is this form of application. In fact, the maglev train built between Shanghai Pudong International Airport and Longyang Road Station of the subway also adopted this form. At that time, German technology was directly introduced, and construction started in 200 1, and it was officially put into use in 2003. The line is 30 kilometers long and only takes 8 minutes. The train has a top speed of 430 kilometers per hour and an average running speed of 380 kilometers per hour. This is the first maglev train in China.
The first commercial maglev line independently developed in China is the line from high-speed railway station to Huanghua International Airport. The project started on May 6, 20 14 and is expected to be completed by the end of May 20 15.
So what's it like to take a maglev train?
The window of the maglev train is a safety deceleration glass, so that passengers can better enjoy the scenery outside the window. Because the maglev train is in suspension when it is running, passengers will feel the slight lifting of the car body at the moment when the train starts and stops running. But it's never obvious and it's safe. When the train is running, there will be no tinnitus, discomfort, palpitation and palpitation caused by high speed, because the maglev train takes this into account, all the windows are made of safety deceleration glass, and the windshield has faded black decorative edges. Therefore, passengers are more comfortable when riding the maglev train.
The speed of maglev train is so high, why hasn't it been widely promoted? The main reasons are as follows:
First, the maglev line is very expensive. The total investment of maglev train in Shanghai Pudong Airport is several billion yuan.
Second, it is difficult to push the Internet on maglev trains. High-speed rail is relatively easy.
Thirdly, after the breakthrough of wheel-rail technology of high-speed rail, the advantages of magnetic levitation are not so obvious, because the speed of high-speed rail can reach 380 kilometers per hour.
Author: Wang Yi
Please indicate the source of the original reprint of this work as "Popular Science China-One-stop Popular Science Principle".
What are the advantages and disadvantages of maglev train? Advantages of maglev train
Maglev train has many advantages: the train is suspended above the rail, and the rail is not in contact with the vehicle, which is not only fast, exceeding 500 km/h, but also stable and comfortable, and easy to realize automatic control; No noise and harmful waste gas, which is beneficial to environmental protection; Can save construction funds; Low operation, maintenance and energy consumption costs.
Disadvantages of maglev train: it is very dangerous for vehicles on land to have no wheels. Because the train has to drop from a great momentum to a standstill, and to overcome a great inertia, it can only be overcome by the braking force of wheels and tracks. Maglev trains have no wheels. It is very dangerous to rely on sliding friction if there is a sudden power failure. In addition, the maglev train is elevated, and it is difficult to rescue at a height of 5 meters when an accident occurs. Without wheels, it is difficult to drag it out of the scene of the accident. If there is a power outage in the section, it is difficult for other vehicles and cranes to get close.