I make a popular science video and all the emperors learn from it!

【Popular science continues】

【2. Modern means of transportation】

【3. Train】

【The development of trains has gone through four stages of development, namely: steam locomotives, electric locomotives, diesel locomotives, and high-speed trains】

【The thermal efficiency of steam locomotives is very low. Only part of the heat of fuel combustion in the boiler is converted into heat energy of steam. The efficiency of the boiler is generally 50% to 80%.%】

【Steam does work in the turbine, and the efficiency of the turbine is only 10% to 15%%】

【In addition, in the transmission of force from the turbine to the wheel shaft, the mechanical efficiency is 80% to 95%%】

【Therefore, the maximum thermal efficiency of a steam locomotive is only 8% to 9%, and fuel is still consumed when parking at a station, preparing and staying in the locomotive depot, so the actual thermal efficiency is only 5% to 7%.%】

【Later, steam locomotives were eliminated because they were too backward, and only a few of them became tourist attractions.】

【second stage:】

【Electric locomotives, also known as electric trains, refer to trains that obtain electric energy from the power supply network (contact network) or power supply rails and then drive the vehicle through the electric motor.】

【The electric energy required for the operation of electric locomotives is provided by the power supply system of electrified railways. Electrically driven diesel locomotives and gas locomotives that carry their own power generation energy and devices do not belong to the category of electric-electric locomotives.】

【Electric locomotives are the product of the second industrial revolution, but it was not until the third industrial revolution that they developed on a large scale and are the main force of modern trains.】

【Electric locomotives have many advantages, and their overall performance is much better than steam locomotives and diesel locomotives】

【Not only widely used in the operation of main line railways, but also serving almost all urban rail transit】

【Nowadays, most countries around the world have begun the construction of electrified railways, popularized the use of electric locomotives, and vigorously developed more advanced electric locomotives.】

【Related history:】

【In 1835, Stratin and Becker from Holland tried to make a battery-powered two-axle small railway vehicle.】

【In 1842, Scot R. Davidson first built a standard gauge electric locomotive powered by 40 batteries and weighing 5 tons. Because the electric motor was so primitive, the locomotive could only barely work】

【In 1879, German W. von Menzi drove a small electric locomotive he designed, dragging three cars with 18 people on board, and performed at the Berlin Summer Exhibition.】

【The locomotive power is supplied by an external 150V DC generator. Power is transmitted to the locomotive through an insulated third rail between the two rails.】

【This is the first successful experiment with electric locomotives】

【The use of electric locomotives for business began in the subway】

【In 1880, Edison in the United States also experimented with electric cars.】

【In 1890, London, the Republic of China, first used electric locomotives to pull vehicles on a 5.6-kilometer-long section of underground railway. Mainline electric locomotives were used in the Baltimore Railway Tunnel section of the United States in 1895, using 675 volts direct current and a dead weight power of 70 watts.】

【At the end of the 19th century, Germany experimented with AC electric locomotives. In 1903, the German three-phase AC electric locomotive set a high-speed record of 210.2 kilometers per hour.】

【In 1895, the first long-distance electric locomotive appeared on the Baltimore-Ohio Railway in the United States. The locomotive weighs 96 tons, has 1080 horsepower and uses 550V power supply.】

【In 1914, Huaxia used 1500 volt DC electric locomotives in Fushun Coal Mine.】

【Main line railway electric locomotives adopt single-phase AC 25000V 50Hz current system.】

【In 1958, the first"Shaoshan" electric locomotive with ignition tube rectification was built.】

【In 1968, the switch to silicon rectifier was successful. It was called"Shaoshan 1" type with a continuous power of 3780 kilowatts. In the future, mainline electric locomotives will develop towards high power, high speed and durability. The speed of passenger electric locomotives has increased from 160 kilometers per hour to 200 kilometers per hour, and is moving towards 250 kilometers per hour. 】(To read exciting novels, go to Feilu Novel Network!)

【In 1958, China's first electric locomotive was born in Zhuzhou, named"Shaoshan", which made great contributions to the electrification of China's railways.】

【Electric locomotives developed rapidly due to their fast speed, strong climbing ability, large traction force, and did not pollute the air. The underground railway also came into being with the emergence of trams.】

【......】

【Locomotive structure:】

【Electric locomotives are composed of three parts: mechanical part, electrical part and air piping system】

【...】

【The main advantage:】

【1. Electric locomotives have the characteristics of high power, fast speed, strong overload capacity, low self-load, large traction and acceleration, short maintenance time, low maintenance, high energy utilization, low operating costs, easy to realize multi-machine traction, and can be used Regenerative braking and clean and environmentally friendly advantages】

【The use of electric locomotives to traction trains can increase the running speed and load-carrying weight of the trains, thus greatly improving the transportation capacity and passing capacity of the railway, which is especially beneficial to the speed increase of old railways.】

【China's Beijing-Guangzhou, Beijing-Shanghai and Beijing-Kowloon trunk railways have undergone electrification upgrades and are now running electric locomotives on a large scale, effectively shortening train travel time.】

【2. Electric locomotives are clean and environmentally friendly and do not produce exhaust gas like steam locomotives or diesel locomotives during operation.】

【Power plants used for gasified railways will control exhaust emissions when using fossil fuels. In addition, they can also use low-pollution wind or hydropower to increase thermal efficiency.】

【In terms of noise, electric locomotives are much quieter than diesel locomotives during operation.】[]

【Therefore, electric locomotives are very suitable for operation on urban rail transit lines.】

【3. In terms of performance, electric locomotives do not need to carry heavy engines and fuel like steam locomotives or diesel locomotives, which can reduce their own weight. Therefore, they are superior to steam locomotives and diesel locomotives in terms of acceleration, deceleration and top speed, and can be further improved. Reduce travel time and is the first choice for high-speed trains, EMUs, etc.】

【......】

The ancients were shocked after reading it.

Are steam locomotives too backward? ? ?

Is this human language?

It was also directly upgraded to an electric locomotive!

"Off the charts! We haven't figured out the steam engine yet, how about you come up with electricity? What is that thing?"

"...Begging".