Electrical technology is an example
of the increasing importance of science
- Engineering education brought science into engineering to a much greater extent that before.
- Rise of science-based technology: at around the same time, electricity was an example of a new area of technology that was more directly based on science than technologies such as canal building or even the machines in textile factories.
Early history of electricity:
- Benjamin Franklin was one of many experimenting with static electricity in the mid-1700s.
- Alesandro Volta invented the voltaic pile in 1800. The idea came from Luigi Galvani, an anatomist, who was dissecting a frog when the frog's legs began to twitch. He thought it resulted from electrical action in the vicinity, such as lightening, stimulating some kind of natural electricity. Volta realized that the metal elements touching the frog's nerves might be the source of the action. Over a period of several years he worked out how to use this effect and produced the first continuous flow of current, from a wet battery.
- Volta's discovery led quickly to the use of electric current to decompose water and to electroplating of metals. In 1810 Davy created an electric arc between two terminals as a source of light. A number of people tried to build telegraphs--using electric current to ring bells, for example, but at first these were not practical.
- in 1820 Oersted discovered that an electric current creates a magnetic field, and Ampere and Faraday started researching the interactions between the two. Faraday used this to make a disk rotate in 1831--the first motor (and generator) but not a useful one.
- Hippolyte Pixii invented the first effective generator in 1832, but it was marginal. The first application of a magneto generator (one with a permanent magnet) to power an arc light was a lighthouse illuminating the Straits of Dover in 1862.
Cooke and Wheatstone telegraph
- Practical telegraphs were invented by Baron Pavel Schilling and Jacobi in Russia and by Cooke and Wheatstone in England--a five-needle system was tried in 1837 for railway use and later simplified--railway signaling is very important but not very demanding. The five needle system used moving needles to point to letters on a board--the operator didn't have to read code but you had to have six wires between the two stations.
- In the U.S. Samuel F. B. Morse used a simple machine--longer or shorter bursts of current pushed a pencil to make a mark on a moving paper tape. The machine was rugged and much cheaper to construct, but the operator had to learn code. By 1837 Morse was transmitting sinals for 10 miles, and in 1843 Congress funded a line between Baltimore and Washington. That line was not widely used, but the line between Washington and New York was profitable.
- By 1850 the telegraph linked all the states east of the Mississippi except Florida. Lines were laid along railroad right of ways, making it easy to get the infrastructure in place.
- The demand for railroad signaling was immediate, and business news could be profitable. Newspapers competed on having the lastest information--it was revolutionary that a St. Louis newspaper could carry President Polk's 1848 message to Congress within 24 hours.
1850s recording telegraph (#55)
There was great eagerness to lay a submarine telegraph between Europe and the U.S.--underwater lines already joined England and France. (lots of history)
- Retired industrialist Cyrus Field took this on as a pet project, and made his first try in 1857, but the cables were not high quality and broke 330 miles out.
- The second attempt with improved cable and better brakes for the cable drums started in June 1858, but again the cable broke repeatedly.
- Another attempt later that year was successful, but the cable ceased to function after about a month due to deterioration by salt water.
- In 1865 another attempt set out to lay a cable of 2300 nautical miles built in a single length--5000 tons of cable. A special ship was built to lay the cable, called The Great Eastern . Only 600 miles from Newfoundland the cable broke, and while it was grappled a couple of times it could not be lifted all the way to the surface.
- In 1866 a new cable was finally successfully laid (and the previous year's one was successfully grappled and raised and repaired as well).
grappling the 1865 cable
The telegraph became the basis for an industry:
- During the Civil War over 6 million messages were transmitted by some 15000 telegraphers, and by the end of 1865 more than 200,000 miles of telegraph line were in service. Increased demand led to the invention of duplex and multiplex telegraph systems.
- Thomas Edison's first major invention, in 1870, was the stock ticker, a special printing telegraph to transmit stock prices from Wall Street.
- arc lights had been invented early in the century, but without an effective power source they weren't very interesting. A few were run by batteries in the 1830s and 1840s, but no further improvements were patented between 1860 and 1870.
- Zenobe T. Gramme (France) invented the dynamo (generator using electromagnets) in 1867 and also showed it could be run backwards as a motor. Gramme was a model maker for a manufacturer of electrical devices; he didn't have a deep knowledge of the theory involved. He developed his dynamo into a system particularly for powering an improved arc light invented in Paris that required alternating current and high voltage. The system was quite widely used in Europe, though it consumed carbons at a very high rate.
- In 1878 Charles F. Brush invented an arc lighting system with a better generator and a simple arc light. This was immediately useful for street lights and other large spaces. Both Brush's company and one started a year later by two Philadelphia high school teachers--Elihu Thomson and Edwin Houston--were commercially successful.
- In 1873 research on generators led to the invention of effective electric motors. Simple motors had been built as scientific toys 40 years earlier, but power from a battery was over 20 times more expensive than power from a steam engine.
- Gas light was fairly sucessful in cities for small-scale lighting, where arc lighting was too bright. A number of inventors starting looking for an alternative, including Thomas Edison.
- Edison was particularly skilled at designing a
whole system
Edison:
- was born 1847, the last of 7 children, educated at home
- At 16 got a job as a telegrapher--wandered around for five years taking jobs in different areas and playing with the machines
- In 1868 he gave up his job and set out to be an inventor
- first patent--vote recording machine--did not sell. Lesson--demand
vote recording machine, Henry Ford Museum, PEM photo
- moved from Boston to NY and got a job on Wall Street. Improved stock ticker (1869) and worked on duplex and quadraplex telegraphs (multiple messages on one wire)
- By age 29 he was successful enough to set up a shop solely devoted to invention.
- improved Alexander Graham Bell's telephone (Bell and Elisha Gray invented the same thing but Bell saw the potential, while Gray, a professional telegraph inventor, did not)
- Edison's next invention was the phonograph in 1878 ( more information , samples )--not a big money-maker but gave him a reputation as a wizard that helped him raise venture capital.
- Meanwhile he was setting up an invention system, hiring mechanics, mathematicians, and eager young inventors. He called his new shop in Menlo Park, New Jersey an "invention factory" and promised a "minor invention every ten days and a big thing every six months or so." ( Edison's patent production , list of patents , The patent system in Edison's time ) In some ways this lab was a precursor of the industrial research laboratory, except it was an independent invention lab, not part of a large corporation. Thomas Edison quotes
Thomas Edison
- Gas utility developed in first half of the 19th century was meeting the need for household light--Edison explicitly set out to compete.
- The arc light was in use for public places, streetlighting, and search lights, after the invention of a practical dynamo about 1870, but was not practical for the home. Edison saw the challenge was to subdivide the light. It was known that incandescent light was a potential solution, but no one had been able to make it work (the filament either melted or burned up)
- scientists said that connecting light bulbs in parallel was impossible
- Edison realized he needed all the parts of the system--improved vacuum pump, efficient dynamo, wiring systems (and the practicalities of that meant that the filament had to have high resistance), meters .
- The hardest problem to solve was the filament--at first Edison thought he could regulate current to a platinum filament so it wouldn't melt. Edison announced he was close to success--stock prices for gas light companies fell. Edison organized the Edison Electric Light Company, backed by investors such as J. P. Morgan and the Vanderbilts. But the platinum filament approach didn't work, despite struggles to find a solution through the middle of 1879.
- Edison had to resort to hiring a Princeton-trained physicist ( Francis Upton ) to help him and eventually (Oct. 1879) to trial and error of over two thousand materials. Finally found a new approach that worked better--carbon instead of platinum. Edison's patent
- On New Years Eve 1879 he put on a big display for press and backers-- got lots of publicity .
- in 1882 he completed the first commercial system--Pearl Street Station ( consequences )
Generators at Pearl Street Station
- Thompson-Houston arc light company and George Westinghouse , who had invented the railway air brake in 1869.
- Westinghouse realized that high voltage would transmit further and that if you used alternating current you could transform it down again for safety.
- Edison fought bitterly against the AC approach --for one thing he didn't have the necessary mathematics.
- Thompson-Houston went to AC and was able to take control of Edison's company in 1892--became GE
- Edison argued that AC was too dangerous and arranged public demonstrations where stray cats and dogs (purchased from local schoolboys for 25 cents each) were electrocuted. He even executed an elephant (video)
- A lot of publicity was carried out not by Edison but by a man named Harold Brown, who had the support of Edison and the technical help of some of Edison's associates.
- In 1888 New York state changed the death penalty from hanging (which sometimes didn't work well) to electrocution, and Edison and his associates lobbyied for the selection of an alternating current design.
- Westinghouse funded appeals by some prisoners who argued that electrocution was cruel and unusual punishment.
- In 1890 Auburn State Prison used the first electric chair to execute a convicted murderer, using Westinghouse alternators.
- "Kemmler was strapped into the chair on August 6, 1890. The first jolt of alternating current lasted 17 seconds. Kemmler continued struggling. A second jolt lasted more than a minute, until smoke was seen rising from the body. It was, The New York Times said, 'an awful spectacle, far worse than hanging.' The state commissioner on humane executions saw it differently. It was, he said, 'the grandest success of the age.' " source , more information on the history of the electric chair , another story
Artist's rendering of Kemmler's execution
Edison's special talents:
- he was an inventor-entrepreneur--good at business
- he thought out the whole system rather than just inventing one gadget
- he was good at finding something useful to do with the results of a failed experiment (1093 patents)
- he also had a particular talent for publicity
Nikola Tesla
Early life:
- born in 1856 in what is now Yugoslavia
- his father was a pastor and wanted Nikola to joint the clergy
- Nikola loved math and physics and when he finished higher Realgymnasium persuaded his father to send him to a polytechnic school in Austria
- he left school in 1878 without finishing his degree (he set off a university in Prague but decided to quit and relieve his parents of the financial burden of his education).
- He worked as an electrician for a telephone company run by a family friend for four years and then when that disbanded for the Continental Edison Company in Paris.
- he had been thinking about a problem with electric motors, and he had an idea for a solution while strolling in a city park in Prague with a friend reciting Goethe's Faust (Tesla was recovering from a nervous breakdown at the time)
- he thought that some of the technical drawbacks of DC motors (sparking and the rapid wearing out of brushes) could be solved with an AC electric motor--he imagined in his mind a motor that needed no contact to carry the current to the moving parts
- he couldn't find backes so he moved to the U.S. in 1884 with a letter of recommendation from the manager of the Paris Edison company to Edison
- Telsa worked for a year for Edison on DC motors and voltage regulators (he left because he didn't get a bonus he had expected). Tesla on Thomas A. Edison: "If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search. I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him ninety per cent of his labor." (New York Times, October 19, 1931)
- Then developed an improved arc light system for a group of NJ businessmen. That was successful, but the businessmen bought him out and he was left without a proper job and ended up digging ditches. His foreman heard he had an idea for an electrical motor and put him in touch with some investors.
- finally in 1887 he found backers in NY to finance a Tesla Electric Company to develop his AC motor . he quickly perfected a promising new system of AC power generation, transmission, and utilization, called polyphase, leading to 7 patents in 1888 . Polyphase uses two alternating currents, 90 degrees out of phase with each other, to power two electromagnets, creating a rotating field. This induces a current in the armature, avoiding the connections that caused so much problems in DC motors. Tesla did the necessary development to make his initial invention practical.
Tesla inventions
- Westinghouse, who had previously invented an air brake for steam locomotives, had gotten interested in AC. He initially bought an Italian transformer and a German AC generator (alternator) and began developing an AC incadenscent lighting system that would transmit AC power at high voltages to reduce transmission losses.
- Westinghouse and his staff developed more efficient transformers and alternators and marketed a very successful system--by 1891 Westinghouse was one of the three leading firms in electric lighting in the U.S.
- Meanwhile electric motors (DC) were coming into use in streetcars, and Westinghouse didn't have an AC motor for his system.
- Westinghouse bought Tesla's design: he paid $75,00 and $2.50/hp royalty that promised $30,000 the first three years and $15,000 in each succeeding year, and also hired Tesla. Demonstrated the system at the 1893 Worlds Fair.
- Trouble was, Tesla had trouble adapting his motor to Westinghouse's AC lighting system, which used only single phase current.
- Everyone got discouraged: Tesla left Westinghouse in 1889 and work on the motor was abandoned for three years. Then Westinghouse decided to go with polyphase, and developed Tesla's whole system, particularly for use at Niagara Falls . A new more mathematically inclined generation of school-trained electrical engineers worked out the new systems.
- He then began investigating high-frequency, high-potential currents from a resonant transformer coil that later became known as the Tesla coil . The Tesla coil is most fundamentally a new kind of transformer that uses a spark gap to transform a low-voltage, low-frequency current into a high-voltage, high-frequency one. He found this intellectually appealing, but it was not a solution to an existing need.
- he patented the idea but did not seek commercial applications--instead he gave lectures about a new field of research. These generated a lot of excitement for a while, in 1893 at a convention of the National Electric Light Association in St. Louis 5000 people attended his lecture. He could light phosperescent gas-filled tubes without any wired connection.
- He was doing something closer to engineering science than invention, but he tended to present it in language that was more romantic than scientific.
Tesla in Colorodo
- He dreamed big--the Tesla coil generated radio
frequencies but Tesla wanted to use it to transmit not just information
but power.
- He visualized a huge Tesla coil that would transmit electrical power anywhere on the planet.
- In 1899 he ran a pilot project in Colorado Springs where he generated sparks up to 135 feet long and conjectured that he transmitted electricity to the Indian ocean (meaning a traveler there could have illuminated a phosphorescent tube). The transmitted energy also knocked out the Colorado Springs power station and caused it to catch on fire. ( source )
- In Colorado Springs, Tesla made what he regarded as his most important discovery-- terrestrial stationary waves . By this discovery he proved that the Earth could be used as a conductor and would be as responsive as a tuning fork to electrical vibrations of a certain frequency.
- He intended this to lead to a World Wireless Power system . He lighted 200 lamps without wires from a distance of 25 miles (40 kilometres). At one time he was certain he had received signals from another planet in his Colorado laboratory, a claim that was met with derision in some scientific journals.
- in 1896 he lost his royalty from Westinghouse--GE and Westinghouse pooled their polyphase and railway patents in an attempt to raise the electrical industry out of an economic slump and Tesla was pressured into relinquishing his motor royalty.
- to replace the income he started to seek a commercial market for the Tesla coil. He got $150,000 from J.P. Morgan in 1900 for a wireless telegraphy plant, and proceded to developed a power station on Long Island , that did not turn into an operating plant for either radio or power transmission.
Tesla's Long Island Station
- he devised a scheme to broadcast electric power without wires using the Tesla coil, but he couldn't get support to develop it
- People did not even really understand his concept of broadcasting power--at this point radio is only used for point to point.
- he had always been eccentric, and became more so (read his Autobiography or here )
- wrote articles for the popular press to advance ideas of the future of electricity
- died in 1943 at the age of 86, penniless and relatively unrecognized
- now he is a hero on the web, see for example Tesla the Electric Magician
- some people think Tesla discovered a way to cause earthquakes that
is being used as a secret weapon
Cowan wants us to think about technology as a system, not individual inventors
- because technology comes in systems it is hard to replace on technology with another. For example, to replace gasoline with hydrogen to power automobiles we would have to put in a whole new set of filling stations
- what I mean by system is all the interdependent technologies and social institutions that are necessary to make use of a technology
- you can't learn much about a technology in isolation--you
need to see it as part of a system
- people were increasingly enmeshed in a technological system
- when we use electricity we are dependent on Duke Power and
on a national distribution system and on coal mining and to a small
extent on oil from the middle east and on nuclear power... How
would it affect us if nuclear power plants were shut down? If
OPEC cut off oil production? If there was a major breakdown in
the electrical distribution system in North Carolina?
This page written and copyright Pamela E. Mack