Current war

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The current war ( English was of currents ) around 1890 was a dispute between Thomas Alva Edison (1847-1931) and George Westinghouse (1846-1914), whether the DC voltage favored by Edison or the AC voltage favored by Westinghouse was the more suitable technology for large-area supply the United States of America with electrical energy and the construction of power grids . At the beginning it was about market shares for their respective electrical companies Edison General Electric , which operated as General Electric from the beginning of the 1890s , and Westinghouse Electric . The current war was the first format war in industrial history - an economic dispute over a technical standard. A cinematic processing took place with the feature films Edison - A Life Full of Light ( The Current War , 2017) and Tesla (2020).

Technical background

Thomas Alva Edison

The beginning of electrification was mainly initiated by the advent of electric lighting, which was initially supplied with electrical energy by batteries. With the discovery of the dynamo-electric principle by Werner von Siemens in 1866 , larger amounts of electrical energy became available for the first time. The invention of the transformer in 1881 by Lucien Gaulard and John Dixon Gibbs made it possible to transport large amounts of energy over long distances at low cost. This is because transformers allow the required electrical active power to be transmitted through a higher voltage with a lower current and thus with lower line losses and transformed back into lower voltages at the customer's site. This development in electrification was supplemented in 1887 with the invention of two-phase alternating current by Nikola Tesla and three-phase alternating current by Dobrowolski in 1888 and forms the two- or three-phase systems commonly used in electrical energy engineering and in power grids today .

Carbon filament lamp, E27 socket, 220 volts, approx. 30 watts, operated on the left at 100 volts

In the early days of electrical power engineering, smaller, regional power grids were set up in the form of island grids, in which the power was mainly used for electrical lighting in carbon arc lamps and carbon filament lamps and to drive smaller direct current motors . The voltage offered was usually 110 V, that is the voltage that had been found to be optimal for the operation of the carbon filament lamp developed by Edison in 1880. The carbon arc lamps, which were installed from 1875 and provided the first public electrical lighting in many cities from 1880, could be operated with 100 ... 110 V direct or alternating voltage.

Edison began to build power plants from 1882, which supplied the electricity for his DC voltage networks. In addition to his patents for carbon filament lamps, he had many other patents on DC technology and demanded license fees for their use as the patent holder. Edison developed one of the first electricity meters to measure the consumption of electrical energy and to be able to bill it accordingly. This electricity meter, known as the Edison meter, could only record direct currents. Edison was aware of the disadvantage of the shorter transmission distance of 110/220 V direct voltage compared to stepped-up alternating voltage, but wanted to generate additional income through this disadvantage by planning a large number of local power generation stations for a range of around 1.5 km in diameter. Westinghouse favored alternating voltage systems with their, at that time, much wider transmission range and began to build these systems from 1886.

At the time, the entrepreneur George Westinghouse was struggling with legal problems with his AC voltage system: under patent law , the manufacturers of incandescent lamps, in particular Edison's companies, often restricted the right to use incandescent lamps sold on licensed power grids. In contrast to Edison, Westinghouse was thus able to offer its customers a high-performance power supply, but not a complete solution, including the incandescent lamps, as it had no patent rights for the production of light bulbs. Hotels and offices with their own generators were successfully ordered to refrain from using their light bulbs. The light bulb manufacturers thus also secured the market for electrotechnical infrastructure and hindered free competition and innovation. These effects of patent law were critically commented on in the newspapers of the time.

A multitude of above-ground telephone, telegraph, and power lines in the streets of New York City are shown in the photo of the great blizzard of 1888. Contact with a broken live AC power line resulted in the death of a person.

After Westinghouse had installed its first large AC power line, Edison wrote in a private letter to Edward Johnson, President of Edison Electric, in November 1886: “Just as certain as death Westinghouse will kill a customer within six months after he puts in a system of any size, He has got a new thing and it will require a great deal of experimenting to get it working practically. ”(Just as sure as death, Westinghouse will kill a customer within six months of putting him in a system of any size got a new thing and it will take a lot of experimentation to get it working in practice) Edison feared bad press from the high voltages in the Westinghouse systems. Safety and harmlessness had been one of the goals in designing his 100V system and he was concerned that a fatal accident could negatively affect electricity as a whole. By the end of 1887, Edison had 121 DC networks and Westinghouse 68 AC networks in the United States. The Thomson-Houston Electric Company had also built 22 AC grids that hampered the expansion of companies in the Edison group. All companies had their own electrical lines, some of which crossed and overlapped.

The city of New York, in which none of the electrical lines were buried until 1887, had a large number of overhead lines for telephone, telegraph, DC and AC voltage lines up to 6000 V, which had been drawn haphazardly through the streets. Insulation on power lines was rudimentary or non-existent. In March 1888, a great snowstorm tore up a large number of the lines and, in addition to a collapse in the energy supply, there was an accident resulting in death from an electric shock. This sparked a public discussion of the dangers of electricity, encouraged in 1888 by an 84-page brochure from Edison Electric Light Co. entitled "A Warning from the Edison Electric Light Company" which stated that DC voltage was not caused a single death.

Course of the dispute

George Westinghouse

The discussion about the dangerousness of alternating voltage did not start directly from Edison, rather politicians and the newspapers dealt with it. The popular Thomas Edison was expected to take a stand. Edison saw the entire electricity business model endangered by possible accidents and the resulting acceptance problems. In particular, the safety of electricity compared to the fire hazard posed by gas was one of his central arguments.

Experiments have been carried out on animals to investigate the unknown effects of electricity on living things. These later aroused outrage among animal rights activists ; at that time, however, the Society for the Prevention of Cruelty to Animals encouraged the development of electrocution as a painless alternative to the then frequent drowning of stray animals. A leading role in the experiments and the public campaign against AC voltage played Harold P. Brown , who was not employed by Edison at the time, but asked for support there and received it. Edison himself played the role of a respected expert. Without naming Westinghouse, he called on politicians to limit the maximum voltage in the various power systems. Brown, on the other hand, asked Westinghouse to publicly expose themselves to an electric shock of the same voltage in DC voltage or AC voltage, since he assumed that AC voltage was more deadly than DC voltage.

Killing convicted people by hanging should also be replaced by the electric chair , which was considered less painful. In 1888 a law was passed in New York. An Edison company got a government contract to develop it. The engineer Harold P. Brown, who works at Edison, used the alternating voltage system of the competitor Westinghouse to discredit it as dangerous. Furthermore, an attempt was made to introduce the saying to be westinghoused for killing with electrical (alternating) current and thus to mock Westinghouse's technology and to miss a negative public image. After this bill was passed, Edison was asked what was the best way to introduce this new type of execution. "Hire your criminals to pull the cords in New York's electric utilities," was Edison's ironic response. Westinghouse felt deeply offended by the experiments, since he did not want anyone to be harmed by his research and tried to resolve the dispute by writing to Edison and an invitation. Edison only replied that his work didn't give him time.

The key product of electrification was incandescent lamps, whose patent rights were owned by Edison. Carbon filament lamps were almost the only consumers of electrical energy in hotels, offices and private households. Edison was able to control the electrical infrastructure via this key product, which is why Westinghouse tried to reduce Edison's market power through company mergers.

The dispute was exacerbated by Westinghouse's purchase of the United States Electric Lighting Co. in 1888, as Edison Electric Light Co. had been litigating this company since 1885 for the patents on incandescent lamps, which it won in all courts, but which only came to a conclusion in 1892. In the pending proceedings, Edison Electric Light Co. had to accept the infringement of their patents. Edison felt betrayed by both of them because of process deferral strategies and because Nikola Tesla - who initially worked for him in Menlo Park , New Jersey - had brought knowledge to Westinghouse.

Nikola Tesla

Nikola Tesla: First employee at Edison in France and the USA, then chief inventor at Westinghouse

Nikola Tesla (1856–1943), who worked for Edison and had left it after a dispute, was contacted a little later by George Westinghouse, who had become aware of him during a lecture. Tesla had invented the principle of two-phase alternating current with a rotating magnetic field in the USA in 1882, at the same time as and independently of Galileo Ferraris in Italy . In the following years there were patent disputes due to the parallel development. On this technical basis, the first two-phase motor was built the following year that worked without wearing brushes . Westinghouse acquired the patent rights to Tesla's so-called polyphase patents, which also include a two-phase motor. He also hired Nikola Tesla as a consultant and began introducing the two-phase electric motor in the US mass market in 1888. This work and the influence of Westinghouse subsequently led to the development of the American power grid with a grid frequency of 60 Hz.

The three-phase alternating current common today in electrical energy networks and the three-phase asynchronous machines that are widely used today as drive motors were developed by Mikhail Ossipowitsch Doliwo-Dobrowolski at the AEG company at the end of the 1880s , regardless of the current war in North America .

Franklin Leonard Pope

George Westinghouse built the first multi-stage AC voltage network in collaboration with Franklin Leonard Pope and William Stanley . It was installed in Pope's home, Great Barrington , Massachusetts in 1886 . A generator powered by a steam engine generated 500 V alternating voltage, which was transformed up to 3000 V and fed into the town. There the voltage was transformed down to 100 V and fed into the houses to supply the light bulbs with energy. Franklin Leonard Pope was a former friend of Thomas Alva Edison and is considered a pioneer for his rise. However, from about 1870 onwards, Pope and Edison had fallen out. Pope died of an electric shock on October 13, 1895 while trying to repair the electricity supply in Great Barrington after a storm. Pope was popular and at times also president of the American Institute of Electrical Engineers . His death led to extensive activities aimed at improving the safety of electrical engineering systems in the United States, which formed the basis of the National Electrical Code . Edison's reaction to the death of his former friend and later adversary in the dispute over AC or DC voltage is not known.

Outcome of the dispute

In the professional world, the decision as to which system is better suited for the energy supply was influenced in 1891 by the successful start of operations of the Ames Hydroelectric Generating Plant and the three-phase transmission from Lauffen to Frankfurt . Westinghouse companies won the prestigious contract to supply their AC voltage system for the 1893 Chicago World's Fair in 1892 . This also included a large number of a light bulb newly developed by Westinghouse, the so-called Westinghouse stopper lamp , which circumvented Edison's patents. Edison was thus defeated in the dispute - the market had opted for the technical advantages of the AC voltage system. Edison was personally stubborn for a long time before he finally admitted his advocacy for the DC system as the biggest mistake of his career.

In the USA, a Westinghouse hydroelectric power station near Niagara Falls ( Niagara Power Station No. 1 ) and the connection of Buffalo to the electrical power supply in 1896 brought about the definitive turnaround in favor of the AC voltage system. After that, General Electric , which emerged from a merger of Edison General Electric Co. and Thomson-Houston Co. in 1892, also produced products for the energy supply infrastructure with AC voltage technology.

In 1896, General Electric and Westinghouse jointly established the Board of Patent Control , which lasted until 1911. This organization settled patent disputes between the companies out of court and represented the patent interests of both companies towards third parties. Information on patent infringements was collected and more than 600 proceedings against third parties were initiated. The personal quarrel between two men was replaced by professional management with decisions based solely on economic considerations at the latest in 1896. Edison had no operational competencies since General Electric was founded . Charles A. Coffin, who was previously head of the Thomson-Houston Co. , which merged with the Edison companies to form General Electric Co. , led the company from the start. Lewis Howard Latimer , who had worked for Edison Companies since 1884, was posted to the Board of Patent Control by General Electric .

After Edison's incandescent lamp patents and Westinghouse's basic patents on AC voltage technology expired, no company was able to control the market technologically.

While the DC voltage networks in Europe had practically disappeared in the middle of the 20th century, the New York electricity supplier Consolidated Edison did not finally stop supplying DC voltage until the end of November 2007. Most recently, older elevators in Manhattan in particular had to rely on the DC voltage supply; in 1998, 4,600 customers were supplied with DC voltage. The elevators were converted to AC voltage or renewed when the supply was stopped with rectifiers .

The term current war

The term " Stromkrieg" ( war of currents ) was not used in the press at the time. The first description of the public dispute between Edison and Westinghouse with current war is not documented. In recent times, the dispute - motivated by discussions about standards such as TV signals, music and video cassettes and DVD formats - has also been interpreted as a system dispute over market dominance through patents on basic technologies.

At that time, the opponents exchanged their views on the dangerousness of alternating current via the press. On December 13, 1888, George Westinghouse wrote in a letter to the editor to the New York Times that AC voltage posed no particular danger. On July 24, 1889, the New York Times reported that Edison was convinced that 1000 VAC could safely kill a person. The documents are exemplary of the appearance of the dispute in the media of the time.

Web links

Individual evidence

  1. ^ W. Siemens: About the conversion of labor into electricity without the use of permanent magnets. In: Annals of Physics. 206, No. 2, 1867, pp. 332-335, doi: 10.1002 / andp.18672060113
  2. ↑ VDE "Chronicle of Electrical Engineering - Transformer" [1]
  3. ↑ Michael Krause: How Nikola Tesla invented the 20th century. 1st edition. Wiley, 2010, ISBN 978-3-527-50431-2 , p. 101
  4. ^ Gerhard Neidhöfer: Michael von Dolivo-Dobrowolsky and three-phase current: the beginnings of modern drive technology and power supply. 2nd Edition. VDE-Verlag, 2008, ISBN 978-3-8007-3115-2 .
  5. ^ Edison Tech Center, The History of Electrification, [2]
  6. ^ Edison Tech Center, The History of Alternating Current: AC Power History and Timeline [3]
  7. ^ Edison Tech Center, The History of the Transformer, [4]
  8. ↑ Helmuth Poll: The Edison counter . Deutsches Museum München, 1995, ISBN 3-924183-30-9 , pp. 30-45.
  9. ↑ Tom McNichol: AC / DC: the savage tale of the first standards war . John Wiley and Sons, 2006, ISBN 978-0-7879-8267-6 , pp. 80 .
  10. ↑ see, for example, Incandescent Lamp Proceedings . In: The Electrical World . Vol. XXII, no. 17, August 5, 1893, p. 94.
  11. ^ Maury Klein: The Power Makers: Steam, Electricity, and the Men Who Invented Modern America. Bloomsbury Publishing USA, 2008, p. 257.
  12. ^ Jill Jonne: Empires Of Light: Edison, Tesla, Westinghouse, And The Race To Electrify The World. Random House Trade Paperbacks, 2004, ISBN 0375758844 , p. 146.
  13. ^ Randall E. Stross: The Wizard of Menlo Park: How Thomas Alva Edison Invented the Modern World. Crown / Archetype −2007, p. 174.
  14. ^ Robert L. Bradley, Jr .: Edison to Enron: Energy Markets and Political Strategies. John Wiley & Sons, 2011, p. 50.
  15. ↑ Quentin R. Škrabec: George Westinghouse: Gentle Genius. Algora Publishing, 2007, p. 97.
  16. ^ Maury Klein: The Power Makers: Steam, Electricity, and the Men Who Invented Modern America. Bloomsbury Publishing USA, 2008, p. 263.
  17. ↑ Mark Essig: Edison and the Electric Chair: A Story of Light and Death. Bloomsbury Publishing USA, 2009, p. 135.
  18. ^ Paul Israel: Edison: A Life of Invention . John Wiley & Sons, 1998, ISBN 0-471-36270-0 , p. 326.
  19. ^ Paul Israel: Edison: A Life of Invention . John Wiley & Sons, 1998, ISBN 0-471-36270-0 , pp. 328-330.
  20. ^ TS Reynolds, T. Bernstein: Edison and "The Chair" . In: IEEE Technology and Society Magazine . tape 8 , no. 1 , March 1989, p. 19-28 , doi : 10.1109 / 44.17683 ( simson.net [PDF]).
  21. ↑ THOMAS ALVA EDISON . In: Scientific American . tape 87 , no. 26 , December 27, 1902, pp. 463-463 , JSTOR : 24986532 .
  22. ^ Jill Jonnes: Empires Of Light: Edison, Tesla, Westinghouse, And The Race To Electrify The World. Random House, 2004, ISBN 0-375-75884-4 , p. 167.
  23. ↑ Patent US381968 : Mode and plan of operating electric motors by progressive shifting; Field magnet; Armature; Electrical conversion; Economical; Transmission of energy; Simple construction; Easier construction; Rotating magnetic field principles. Patent US381969 : Novel shape and operating mode; Coils forming independent energizing circuits; Connected to an alternating current generator; Synchronous motor. Patent US381970 : Current from a single source of supply in the main or Transmitting circuit induce by induction apparatus. Patent US382279 : rotation is produced and maintained by direct attraction; Utilizes shifting poles; Induction magnetic motor. Patent US382280 : New method or mode of transmission; Dynamo motor conversion with two independent circuits for long distance transmission; Alternating current transmission. Patent US382281 : Improvements in electromagnetic motors and Their fashion or methods of Their operations. Patent US382282 : Method of Converting and Distributing Electric Currents. ‌





  24. ^ Gerhard Neidhöfer: Michael von Dolivo-Dobrowolsky and three-phase current: the beginnings of modern drive technology and power supply . 2nd Edition. VDE-Verlag, 2008, ISBN 978-3-8007-3115-2 .
  25. ^ Great Barrington 1886 - The first practical AC power delivery system. Edison Tech Center, 2010, accessed October 27, 2013 .
  26. ^ Ames Hydro: Making History Since 1891. In: HydroWorld.com. August 27, 2013, accessed October 27, 2013 .
  27. ^ Ed Reis: Early Lamps by Westinghouse. (PDF) (No longer available online.) Engineers' Society of Western Pennsylvania, 2005, archived from the original on October 29, 2013 ; accessed on December 29, 2013 .
  28. ↑ 1890's Incandescent Lamps: 1893 New Beacon Stopper Lamp. In: Past Technology . 2000, accessed December 29, 2013 .
  29. ^ Niagara Falls History of Power: In Search of Long Distance Transmission. In: Niagara Falls Thunder Alley . Rick Berketa, accessed December 29, 2013 .
  30. ↑ Con Edison, press release of November 14, 2007 ( Memento of the original of September 8, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.coned.com
  31. ^ No Special Danger .; Alternating Currents In Electric Light Wires. In: The New York Times. December 13, 1888 ( New York Times online archive , accessed December 29, 2008).
  32. ^ Testimony Of The Wizard; Edison's Belief In Electricity'S Fatal Force. He Is Positive That An Alternating Current Of 1,000 Volts Would Surely Kill A Man. In: The New York Times. July 24, 1889 ( New York Times online archive , accessed December 29, 2008).