From Franklin's discovery of electricity to Faraday's discovery of the law of electromagnetic induction, scientists are eager to crack the code of this magical physical phenomenon. The beginning of our story begins with 1802 (it will be earlier if the whole picture of electrical development has been unfolded). At that time, scientists in the laboratory had been able to generate a stable current through electrochemical reactions. At that time, the famous British chemist Sir humphry davy (named in 18 12) heated different metal rods with electric current, and found that platinum wire could remain incandescent for a period of time without being oxidized, which was the first time that human beings converted electric energy into light energy.
At that time, people's cognition of electricity was limited to generating sparks, which represented the existence of electricity. 1809, David connected two carbon rods at the two ends of a high-power battery, without touching each other, and there was an arched spark between the carbon rods, so it was called "arc", which is the basic principle of arc lamp. David's two discoveries laid the foundation for the invention of incandescent lamp and arc lamp respectively.
There are two other things worth mentioning about Sir Humphrey David. One is his personal achievements. He discovered and made many elements, including calcium, magnesium, sodium, potassium, strontium and barium. He is recognized as the scientist who discovered the most elements, also known as "inorganic chemistry". Second, David discovered Faraday's talent and led him to the door of science. Although the master and the apprentice experienced some unpleasantness, David still proudly thought Faraday was his greatest discovery before his death.
So in the next 70 years, scientists and scholars from all walks of life invented various forms of incandescent lamps and arc lamps. The following are only representative examples of the invention:
1840, Sir William Robert Grove invented the experimental lamp shown below. He connected two copper wires at both ends of the platinum wire and coated it with insulation. Then he put the platinum wire as a filament in the glass inverted in water to prevent the incandescent wire from being cooled by airflow and reduce the platinum wire from being oxidized by oxygen. The incandescent lamp invented by Sir Grove can only emit weak light, and it consumes too much electricity to be commercialized.
184 1 year, another Englishman, Frederic de Mo reines, obtained the patent for the world's first incandescent lamp. The upper tube of this spherical incandescent lamp is filled with carbon powder, and the opening at the lower end provides carbon powder for two platinum wires. However, due to the volatilization of carbon powder at high temperature, the spherical glass will turn black quickly, which is still not practical.
In the next 20 years, incandescent lamps with different shapes came out one after another, but they were not put into use on a large scale because of many problems such as high cost, short light-emitting time and black shell.
1860, joseph swan, an Englishman, made a carbon filament electric lamp, but it was limited by technical conditions. At that time, he failed to create a good vacuum environment for filament to work continuously. It was not until 1878 that the vacuum technology in Britain was developed to meet the needs. He invented a light bulb powered by carbon wire under vacuum and obtained a British patent. 1879, Swan was able to publicly demonstrate his incandescent lamp to the audience in his speeches in various places. In the same year, he established Swan Electric Light Bulb Co., Ltd., and realized the private and commercial production of incandescent lamps. The Swan House in Gateshead is the first private house with electricity in the world.
In Russia, 1872, the scientist Lodyguine invented an incandescent lamp with V-shaped graphite as fuel and filled with nitrogen. Because of the high operating cost and short service life (12 hours), this project also ended in failure.
1874, two electricians in Canada invented a technology that filled a glass bulb with nitrogen to make it glow together with the electrified carbon rod. However, due to their lack of follow-up funds, this technology was sold to our familiar Edison at 1875. The names of these two electricians have not been found.
After Edison bought the patent of incandescent lamp, he began to prepare for the invention of incandescent lamp in the summer of 1878. He will not only invent the incandescent lamp, but also invent a complete power system, which can provide electricity to users like gas.
Edison made many miracles in the late 1970s of 19 and the early 1980s of 19, including the incandescent lamp-Menlo Park Laboratory, the most well-equipped private industrial R&D room in the world. Here, Edison and his experimenters improved the telephone, invented the phonograph, and developed commercial electric lights and power systems. In Menlo Park, Edison summed up three elements that formed the road of innovation for the rest of his life: team-based research, enterprise support for research and development, and his own brand image as a reliable and practical inventor to encourage investors to fund laboratories and inventions.
The improvement of incandescent lamp and the invention process of power system have a good foundation because of a reliable team and a repaired laboratory.
1September, 877, Edison incandescent carbonized paper tape. Because there was no vacuum pump with excellent performance at that time, it was impossible to build an effective vacuum environment, and the carbonized paper tape quickly failed in the oxidation experiment.
After Edison learned more about the arc lighting system and the newly invented generator, he put forward two new ideas: to cut off the circuit before the filament overheats to ensure that the filament does not fuse, and to make each lamp work independently by connecting light bulbs in parallel. 1On September 3, 878, Edison applied for a patent for his existing idea and said in The New York Sun that electric lighting would be cheaper than gas lighting. But in fact, Edison has not improved or invented the incandescent lamp that can work for a long time at this stage.
At the end of September, Edison's lawyer began to discuss with some interested investors. Finally, on June 6 10, Edison electric lamp company was established with a total capital of 300,000 USD. Edison granted the company exclusive control over the electric light patents in the north and south of the United States. In return, he received $250,000 in company stock, $30,000 in experimental expenses, and another $65,438+000,000. On the premise of guaranteeing the minimum annual salary 15000 USD, he got a royalty of 5 cents for each lamp sold by the company.
The above is Edison's preparation for the establishment of his electric light and power system, and it is also a step that must be completed before the great scientific experiment-raising funds.
1In the autumn of 878, experimenters in Monroe Park began to design the whole system of incandescent lamps, including switches, meters and power distribution systems. Because Edison was not satisfied with Wallace's generator, the experimenter had to start designing a new generator. Until March 1879, Edison's team designed a platinum lamp that could be demonstrated and placed in vacuum.
On June1879 65438+1October 2 1, the laboratory began to test the carbon yarn, and the test effect of carbonized cotton yarn was the best. On February 2nd, 65438+KLOC-0/day, the first edition of The New York Herald published a long article "Brilliant Achievements of Great Inventors in Electric Lighting". In the last week of 65438+February, hundreds of tourists came to Monroe Park Laboratory to visit Edison's first electric light exhibition in the laboratory. Edison's electric light became famous for a while.
Edison's patent is controlled by Edison Electric Company, and its board of directors is unwilling to invest in production and operation. They are more inclined to sell the licensing rights of new technologies. In order to control the cost and continue to improve the electric lighting technology and production methods, Edison could only manufacture the system in his own workshop.
1880, Edison bought an abandoned factory near Menlo Park to produce incandescent lamps, workers produced vacuum pumps, and experimenters continued to improve light bulbs. After several months of investigation, Japanese bamboo filament was finally determined as the filament. In the same year, Edison established Edison Electric Light Company to manage the factory and new york Edison Lighting Company. 188 1 February, the first land-based lighting system landed in a printer company in new york. On March 4th, Edison set up the Electric Pipeline Company. In the same month, Edison Machinery Factory was established with Butler to produce large-scale equipment such as generators in lighting systems; In April, Bergman Company was established to produce lamps, create independent lighting and manage the business of independent power plants. In August, Edison bought several warehouses from 255 to 257 Pearl Street and began to build the first power plant in the United States. The original transmission range of DC power supply system is about 1.6 km, but according to the actual situation, the transmission range is reduced to 1 km with Pearl Street Power Plant as the center. After the transformation of the warehouse, four large coal-fired boilers were installed on the first floor to provide pressurized steam to drive generators. The generator is installed on the second floor, weighing 2 1 ton, and can generate 100kW, which is enough to supply power for 1 0,200 lamps. Edison named it "Big Mac". 165438+ 10 In October, Edison established an independent lighting company.
1882, Morgan decided to show Edison's lighting system in his luxurious mansion on Madison Avenue. On the evening of June 7, Morgan's mansion was brightly lit. Driven by Morgan's move, in the autumn of 1882, direct current was transmitted to the pre-contracted buildings of 59 customers through underground cables, and new york became the first city to be lit by incandescent lamps. In order to ensure that all users can use the lamp safely and stably, and prevent the filament from burning out due to high voltage, and the brightness is unstable due to low voltage, Edison chose the DC voltage of 1 10kV as the transmission voltage.
By the spring of 1883, Edison * * * had sold 330 independent systems, providing power for more than 64,000 lamps.
With the construction of DC system in full swing, its short transmission distance is becoming more and more prominent. Electric energy can only be effectively transported to the area less than 2 kilometers away from the central power plant, beyond which the voltage will be greatly reduced. Edison's DC system must build dozens of power plants to serve the whole city of new york, which is unrealistic for a city with high land price like new york.
If you want to increase the transmission voltage, you can only achieve it by connecting DC generators in series. As mentioned above, the DC generator is huge, and the problem of filament burning needs to be considered. The transmission distance is severely limited, and DC boost is difficult to achieve. In order to reduce line loss, thicker copper wire is needed. Copper is an indispensable raw material for power industry, but the price of copper suddenly rose from 10 cents per pound to 16 cents per pound in 187, which had a considerable impact on DC power supply system.
Last time Edison's DC power supply system encountered the problem of power supply distance. Although Edison and his company tried to solve it, the problem could not be solved, at least not well. The best way to solve the problem of power supply distance is to adopt AC transmission, which is DC's strongest competitor.
1882, French scientist Goulard and Englishman Gibbs applied for the patent of AC distribution system together. Transformer AC power supply can be conveniently used to boost the voltage, and high-voltage power supply can be transmitted to a longer distance, and then step down the voltage for users. The appearance of communication effectively solved the problem of power supply distance. When it comes to communication, we have to mention two people: Westinghouse and Tesla.
Nikola tesla arrived in new york on the Richmond City at the beginning of June 1884. When Tesla set foot on the land of Manhattan, the Statue of Liberty was still under construction. Edison's first factory using electricity was only two years old in Pearl Street.
On the second day in America, Tesla, 28, visited Edison, 37. At this time, Edison's headquarters was located at 65 Fifth Avenue in New York. He disdains Tesla's dependence on mathematics and shows off that he doesn't care about scientific theory. Although their first meeting was not perfect, Edison hired Tesla to repair the lighting system on the Oregon ship that afternoon.
Within six months after starting work, Tesla designed more than 20 kinds of machines to replace Edison's inefficient old machines, saving a lot of money. But no matter how Tesla recommended communication technology, Edison was not interested. Their final breakup stemmed from an unfulfilled promise. Tesla thinks he can greatly improve the efficiency of Edison's generator. Edison promised that if someone could successfully improve the efficiency of the generator, he would get a reward of 50 thousand dollars. Half a year later (about188465438+early February), Tesla really tripled the power of Marianne's generator, but Edison refused to pay $50,000, saying that he didn't understand American humor. Although Edison still proposed a 55% salary increase, this did not prevent Tesla from leaving.
After leaving Edison Company, Benjamin Vail, a member of Parliament from Lowe Town, New Jersey, extended an olive branch to Tesla. Together, they established Tesla Electro-optic Manufacturing Company, aiming at establishing a perfect arc lighting system for Lowe Town. Tesla spent a year improving the generator and electric light (arc light) and gave the patent to the company in exchange for shares. 1886, the town of Willa had a "perfect automatic and self-regulating arc lighting system", but Weil only wanted to operate and maintain the existing power system, and pushed Tesla out of the company.
After losing his job, Tesla once made a living by digging cable trenches. At the most difficult moment, he completed the patent application for thermomagnetic motor, which was appreciated by the ditch digger, and introduced him to Alfred Brown, general manager of new york Western Union Telegraph Company, and then Tesla was introduced to Charles Peck, a part-time patent lawyer of United Telegraph Company.
1887 In April, Tesla, Brown and Peck jointly established Tesla Power Company, which stipulated that inventors could get one-third of the company's profits. Tesla didn't have to worry about money and life for the time being, and finally had his own laboratory. Later, he developed a commutator that can reduce the spark generated by the motor and a short-circuit commutator that can improve the efficiency of the DC generator, but it was frustrated in the patent application of the thermomagnetic generator. This time, his partner did not abandon him, but encouraged him to do research in other directions first and wait for the opportunity. In such a friendly and harmonious atmosphere, Tesla is actively creating his inventions all year round and preparing to apply for a patent. At this time, Tesla hopes to unify the standards of the power industry through the invention and promotion of alternators.
1888 in may, 7 patents covering various technical inventions such as AC motors were approved. During the spring and summer of 1888, Tesla developed more than 20 different types of multiphase motors, which are suitable for different scenes, such as heavy-load starting, different-speed operation and constant-speed operation. These motors were later applied to heavy machinery, refrigerators, fans and other fields.
Some people are interested in DC systems, while others are betting on air conditioning systems. George Westinghouse purchased many patents, including induction motors and transformers. After learning about Tesla's many inventions about AC motors, he sent his own legal advisers and technical experts to investigate. Both experts believe that Tesla is the best car they have ever seen, so Peck's request for a patent purchase fee of $200,000 and a patent tax of $2.50 per horsepower has also been accepted by Westinghouse.
1In mid-July, 888, Tesla sold more than 20 patents to Nishiya Company, obtained 150 shares and a patent fee of $2.5 per horsepower, and was invited to Pittsburgh for further invention research. 1In late July, 888, Tesla was invited to Pittsburgh.
Westinghouse is also a great inventor. He holds more than 400 patents, most of which are related to railway braking. At the beginning of the cooperation, he expected Tesla's motor to be integrated with the company's single-phase circuit, and the current was 133 Hz (there was no concept of Hz at that time). After the failure, Westinghouse employees changed the frequency of the central power station to adapt to the frequency of Tesla motors. This frequency needs to be high enough, not only to stop the flashing of the lamp, but also to drive the motor to run effectively, and finally set it at 60 Hz. In less than ten years, 60 Hz has become the standard of power production. 1889 Tesla produced 15 patents, which was the year in which he applied for the most patents. Westinghouse * * * produced nearly 1000 Tesla motors.
/kloc-in the midsummer of 0/889, Tesla returned to new york after a trip to Europe, and invented the Tesla coil, a kind of "light-emitting tube" similar to the lightsaber in Star Wars, which is also the result that he will definitely show in his later speech activities. The invention of AC motor and high-frequency coil made him famous.
After signing a contract with Tesla, Westinghouse developed too fast and borrowed heavily to expand its industry. When the economy collapsed, creditors demanded to withdraw their funds, so the company wanted to recover Tesla's high patent fees. Westinghouse renegotiated with Tesla, and Tesla tore up the contract and gave up the patent fee.
DC transmission system and AC transmission system had a competitive relationship from the beginning of their invention, and the outcome was still unclear until the late period of 1880. Edison and the financiers behind him have mastered most of the projects and funds, while Tesla and Westinghouse have power systems that they think are more efficient and powerful. But both power modes must compete with natural gas companies. The risk of this struggle is as great as the potential profit.
Westinghouse invited Edison to visit the laboratory in Pittsburgh 1888, but Edison flatly refused Westinghouse's invitation. From 65438 to 0890, Edison launched a large-scale public relations campaign against alternating current, including publishing an 84-page abusive article, lashing out at Westinghouse Electric. Westinghouse replied to one of his power manuals, accusing Edison of poor safety record, indicating that Edison's DC central power station often caught fire.
At this point, the war has developed to a more creepy place. Edison and his business partner harold brown jointly killed a dog in a public exhibition. Since then, Brown has continued to carry out this experiment on more than 50 different animals, including dogs, cats, calves and horses, in order to publicize that alternating current meets all the conditions as an electric shock medium. With the cooperation of a series of cruel demonstrations, Edison suggested to the legislature of new york to use alternating current to execute electrocution, and he even outlined the specific electrocution steps himself. Finally, his lobbyists persuaded the New York State Government to set up electrocution chairs in two state prisons in new york. Witnesses who witnessed the first electrocution were frightened by the sight of the condemned man's body on fire. The New York Times reports: "The stench is unbearable." The execution turned public opinion against Edison's ideas and practices, and Edison's remarks put him in an awkward position.
Tesla joined the debate by writing an article introducing his invention. 189 1 February, Tesla described in detail the whole process of safe long-distance transmission of alternating current in Power Engineer, and then Edison and he had a heated debate in a series of letters from readers of industry magazines, which lasted from winter to the following spring.
In order to let the public know more about alternating current, in May of the same year, Tesla gave a speech to the American Institute of Electrical Engineering at Columbia University in new york. Tesla's speech and live demonstration fascinated the experimenters, journalists and financiers attending the meeting. In order to expose Edison's statement about the danger of alternating current, Tesla let thousands of volts of alternating current pass through his body, releasing tiny sparks from his fingertips, while the inventor himself was safe and sound.
So the shy inventor became more and more famous, and he had to face the attack of those legitimate competitors. 1892, Tesla decided to go to Europe to defend its patent right and promote its invention to European manufacturers. 1In February, 893, the total amount of lighting equipment provided by the AC system sold by Westinghouse Company was 13 times that of Edison Company.
When Tesla gave various lectures, Edison's company was integrated into "Edison General Electric Company", and Thomson Houston Company, which had been competing with Tesla for the patent of AC motor, was also acquired by General Electric at 1892. Edison kept a place on the board of directors of the new company, but his name no longer appeared in the name of the new company "General Electric Company", which made him suffer greatly.
At this stage, Tesla seems to be better at public relations in the battle between AC and DC, but without Edison, GE made a lot of money. The final decisive battle between the two sides will be staged at 1893 Chicago World Expo to commemorate the 400th anniversary of Columbus' landing on the American continent.
Because the price quoted by General Electric Company is outrageous, all the electric lamps and motors supplied and operated for Chicago World Expo were won by Westinghouse at half the price quoted by General Electric Company, and instead of using Edison's incandescent lamp patent, two-stage electric lamps developed by Tesla and Westinghouse engineers were used.
Electric lights are not the only challenge facing the west roof. What Chicago needs is enormous. Westinghouse Electric-Tesla team upgraded motors and transformers, and expanded the power of more than ten generators. After the upgrade, an engineer can operate 40 different circuits in this and that Expo site.
Tourists and scientists leave the Expo site convinced that the future of energy belongs to electricity and the future of electricity belongs to alternating current. After the World Expo, 80% of the electrical appliances ordered by the United States belonged to Tesla's design, and alternating current gradually locked in the victory of the electric war.
With this victory, Westinghouse Electric and Tesla turned to seek huge business opportunities for building hydropower facilities in Niagara Falls. 1in June, 893, Westinghouse won the key contract for Niagara Falls with a bold plan.
1896 165438+1October16, Westinghouse pushed the switch of Niagara Hydropower Station, ending the power war!
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