Supplemental Material: War of Currents

Transcription

1 Supplemental Material: War of Currents Jerome P. Lynch, Ph.D. Department of Civil and Environmental Engineering Department of Electrical Engineering and Computer Science University of Michigan CEE370 Sensors, Circuits and Signals University of Michigan 2014, Jerome P. Lynch

2 Brief Biography: Thomas Edison Born 1847 in Milan, Ohio Raised in Port Huron, Michigan During Civil War served as a telegraph operator later moving to Boston to work for Western Union and to take classes at Boston Tech (became MIT in 1916) A few of his inventions: Harmonic telegraph (with Bell) Carbon transmitter (early phone) Phonograph Incandescent light bulb Electrical distribution system Vitascope for silent movies Founder of General Electric (GE) Died 1931 in Glenmont, NJ 2

3 Nicola Tesla Brief Biography: Born 1856 in Smiljan, Croatia Student at Austrian Polytechnic in Graz Austria from studying engineering 1881 Budapest Telephone Exchange 1882 Continental Edison Company (France) 1884 Edison Machine Works (NYC) redesigning Edison DC generators: Edison promised him $50K if he could redesign Edison s motors to have improved efficiency. After doing it, Edison reneged on the deal and Tesla quit Tesla Electric Light & Manufacturing Introduce AC distribution, motor and lighting system Brushless AC inductive motors Teamed up with Westinghouse to market AC power Other inventions: Wireless transmission of power Died 1943 in New York City 3

4 George Westinghouse Brief Biography: Born 1846 in Central Bridge, NY 1863 served in the NY Cavalry during Civil War 1864 served as an engineer in the Navy 1867 moves to Pittsburgh, PA Worked in rail industry from 1869 to 1880 Early inventor of the modern air brake system used on modern railroads Earlier brakes were manually applied 1881 started Union Switch and Signal Company marketing signaling solutions in the rail industry Due to signaling networks, interested in electrical distribution networks 1886 founded Westinghouse Electric Corp 1888 licenses Tesla s patent on inductive motors Died 1914 in New York City and buried in Arlington National Cemetery 4

5 DC versus AC Power War of Currents Two powerful inventor/industrialists: Edison and Westinghouse/Tesla Both teams are seeking to implement electrical distributions systems DC Current: Edison seemed to have a jump on it with the light bulb in 1879 DC electricity difficult to transmit over long distances efficiently Tesla was hired by Edison to explore the problem of power loss Tesla concluded in 1885 that AC was the key but Edison was dismissive AC Power: Could be transmitted over long distances very efficiently and inductive turbines and motors could easily be attached to an AC grid 1885 Tesla starts Tesla Electric Light & Manufacturing 1888 Westinghouse licenses Tesla s patents as he builds momentum Westinghouse was a real threat to Edison because he not only had technology but also cash and access to markets which Tesla did not 5

6 Edison DC Efforts 1882: Pearl Street DC Power Plant in lower Manhattan: Porter Allen steam engine DC generator to power 2 wire station Replicated this system design across country in urban areas Many black outs though given the imperfect system he assembled Transitioned to a 3 wire standard in Brockton, MA which proved the robustness of DC power systems But power could only be distributed about 3 miles from the station 6

7 Westinghouse AC Efforts AC power known to be more efficient: Can carry high voltage, low current electricity for 100 s of miles AC transformers can step voltages up and down Westinghouse first to implement an AC power system in Great Barrington, MA using hydroelectric power and transmitting power at 1000 V (user loads stepped down by transformer to 100 V) Quickly adopted in suburban and rural areas because of ability to transmit electricity over long distances 1893 World Fair in Chicago featured Westinghouse AC electricity 7

8 War of Current Edison Westinghouse War of Currents occurred for many years on different playing fields: Westinghouse routinely sold AC power systems at a loss to undermine Edison in the marketplace: Edison bid $554,000 to implement DC power at 1893 World Fair Westinghouse bid $399,000 to implement AC power at the fair Edison sought to have federal law implemented limiting the maximum voltage electricity could flow at (800 V because AC was at the time was transmitted at 1000 V) AC power eventually won out after 1893 World Fair where Westinghouse gain significant notoriety for AC power systems 8

9 War of Current 1887 Edison was approached by Dr. Alfred Southwick to explore the possibility of death by electrocution Edison initially declined due to his opposition to capital punishment but in 1888 he changed his mind and got involved Used AC power to electrocute animals to show it is a dangerous Behind the scene advocate for use of AC in design of first electric chair William Kemmler first AC electrocuted prisoner in 1890: Westinghouse provided legal counsel making case at the US supreme court that electrocution was cruel and unusual punishment 9