NationMaster - Encyclopedia: War of Currents

In the "War of Currents" era (sometimes, "War of the Currents" or "Battle of Currents") in the late 1880s, George Westinghouse and Thomas Edison became adversaries due to Edison's promotion of direct current (DC) for electric power distribution over the alternating current (AC) advocated by Westinghouse and Nikola Tesla. // Development and commercial production of electric lighting Development and commercial production of gasoline-powered automobile by Karl Benz, Gottlieb Daimler and Maybach First commercial production and sales of phonographs and phonograph recordings. ... This article does not cite any references or sources. ... Edison redirects here. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... For delivered electrical power, see Electrical power industry. ... City lights viewed in a motion blurred exposure. ... Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ...

Introduction

During the initial years of electricity distribution, Edison's direct current was the standard for the United States and Edison was not disposed to lose all his patent royalties. Direct current worked well with incandescent lamps that were the principal load of the day, and with motors. Direct current systems could be directly used with storage batteries, providing valuable load-levelling and backup power during interruptions of generator operation. From his work with rotary magnetic fields, Tesla devised a system for generation, transmission, and use of AC power. He partnered with George Westinghouse to commercialize this system. Westinghouse had previously bought the rights to Tesla's polyphase system patents and other patents for AC transformers from Lucien Gaulard and John Dixon Gibbs. 11kV/400V-230V transformer in an older suburb of Wellington, New Zealand Electricity distribution is the penultimate stage in the delivery (before retail) of electricity to end users. ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... It has been suggested that Magnetic field density be merged into this article or section. ... This article does not cite any references or sources. ... A polyphase system is a means of distributing alternating current electrical power. ... For other uses, see Transformer (disambiguation). ... Lucien Gaulard (1850 - November 26, 1888) invented devices for the transmission of alternating current electrical energy. ...

Several undercurrents lay beneath this rivalry. Edison was a brute-force experimenter, but was no mathematician. AC cannot really be understood or exploited without a substantial understanding in mathematics and mathematical physics, which Tesla had. Tesla had worked for Edison but was undervalued (for example, when Edison first learned of Tesla's idea of alternating-current power transmission, he dismissed it: "[Tesla's] ideas are splendid, but they are utterly impractical."^[2]). Bad feelings were exacerbated because Tesla had been cheated by Edison of promised compensation for his work.^[3]^[4] Edison would later come to regret that he had not listened to Tesla and used alternating current.^[5]

Electric power transmission

The competing systems

Edison's DC distribution system consisted of generating plants feeding heavy distribution conductors, with customer loads (lighting and motors) tapped off it. The system operated at the same voltage level throughout; for example, 100 volt lamps at the customer's location would be connected to a generator supplying 110 volts, to allow for some voltage drop in the wires between the generator and load. The voltage level was chosen for convenience in lamp manufacture; high-resistance carbon filament lamps could be constructed to withstand 100 volts, and to provide lighting performance economically competitive with gas lighting. At the time it was felt that 100 volts was not likely to present a severe hazard of electrocution. Sign warning of possible electric shock hazard An electric shock can occur upon contact of a humans body with any source of voltage high enough to cause sufficient current flow through the muscles or hair. ...

To save on the cost of copper conductors, a three-wire distribution system was used. The three wires were at +110 volts, 0 volts and −110 volts relative potential. 100-volt lamps could be operated between either the +110 or −110 volt legs of the system and the 0-volt "neutral" conductor, which only carried the unbalanced current between the + and − sources. The resulting three-wire system used less copper wire for a given quantity of electric power transmitted, while still maintaining (relatively) low voltages. However, even with this innovation, the voltage drop due to the resistance of the system conductors was so high that generating plants had to be located within a mile (1–2 km) or so of the load. Higher voltages could not so easily be used with the DC system because there was (at the time) no efficient low-cost technology that would allow reduction of a high transmission voltage to a low utilization voltage. A split phase electricity distribution system is a 3-wire single-phase distribution system, commonly used in North America for single-family residential and light commercial (up to about 100 kVA) applications. ... Ground or earth in a mains (AC power) electrical wiring system is a conductor that exists primarily to provide a low impedance path to the earth to prevent the buildup of voltages, static or transient (lightning), that may result in undue hazards to connected equipment or persons, and which in... This article or section does not cite its references or sources. ...

In the alternating current system, a transformer was used between the (relatively) high voltage distribution system and the customer loads. Lamps and small motors could still be operated at some convenient low voltage. However, the transformer would allow power to be transmitted at much higher voltages, say, ten times that of the loads. For a given quantity of power transmitted, the wire size would be inversely proportional to the voltage used; or to put it another way, the allowable length of a circuit, given a wire size and allowable voltage drop, would increase approximately as the square of the distribution voltage. This had the practical significance that fewer, larger, generating plants could serve the load in a given area. Large loads, such as industrial motors or converters for electric railway power, could be served by the same distribution network that fed lighting, by using a transformer with a suitable secondary voltage. For other uses, see Transformer (disambiguation). ...

Early transmission analysis

Edison's response to the DC system limitations was to generate power close to where it was consumed (today called, distributed generation) and install large conductors to handle the growing demand for electricity, but this solution proved to be costly (especially for rural areas which could not afford building a local station^[6] or paying for massive amounts of very thick copper wire), impractical (including, but not limited to, inefficient voltage conversion), and unmanageable. Edison and his company, though, would have profited extensively from the construction of the multitude of power plants required for introducing electricity to many communities. Distributed generation generates electricity from many small energy sources. ...

Direct current could not easily be changed to higher or lower voltages. This meant that separate electrical lines had to be installed in order to supply power to appliances that used different voltages, for example, lighting and electric motors. This led to a greater number of wires to lay and maintain, wasting money and introducing unnecessary hazards. A number of deaths from the Great Blizzard of 1888 were attributed to collapsing overhead power lines in New York City.^[7]^[8]^[9] This article or section does not adequately cite its references or sources. ...

Alternating current could be transmitted over long distances at high voltages, at lower current for lower voltage drops (thus with greater transmission efficiency), and then conveniently stepped down to low voltages for use in homes and factories. When Tesla introduced a system for alternating current generators, transformers, motors, wires and lights in November and December of 1887, it became clear that AC was the future of electric power distribution, although DC distribution was used in downtown metropolitan areas for decades thereafter. 1887 (MDCCCLXXXVII) is a common year starting on Saturday (click on link for calendar) of the Gregorian calendar or a common year starting on Monday of the Julian calendar. ... This article is in need of attention. ...

Low frequency (50 - 60 Hz) alternating currents can be more dangerous than similar levels of DC since the alternating fluctuations can cause the heart to lose coordination, inducing ventricular fibrillation, which then rapidly leads to death within six to eight minutes from anoxia of the brain and medulla. ^[10]. High voltage DC power can be more dangerous than AC, however, since it tends to cause muscles to lock in position, stopping the victim from releasing the energised conductor once grasped. However, any practical distribution system will use voltage levels quite sufficient for a dangerous amount of current to flow, whether it uses alternating or direct current. Since the precautions against electrocution are similar, ultimately, the advantages of AC power transmission outweighed this theoretical risk, and it was eventually adopted as the standard worldwide. Ventricular fibrillation (V-fib or VF) is a cardiac condition which consists of a lack of coordination of the contraction of the muscle tissue of the large chambers of the heart that eventually leads to the heart stopping altogether. ... City lights viewed in a motion blurred exposure. ...

Download high resolution version (516x806, 50 KB)Electric system US390721 This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Download high resolution version (516x806, 50 KB)Electric system US390721 This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...

Transmission loss

The advantage of AC for distributing power over a distance is due to the ease of changing voltages with a transformer. Power is the product of current x voltage (P = IV). For a given amount of power, a low voltage requires a higher current and a higher voltage requires a lower current. Since metal conducting wires have a certain resistance, some power will be wasted as heat in the wires. This power loss is given by P = I²R. Thus, if the overall transmitted power is the same, and given the constraints of practical conductor sizes, low-voltage, high-current transmissions will suffer a much greater power loss than high-voltage, low-current ones. This holds whether DC or AC is used. However, it was very difficult to transform DC power to a high-voltage, low-current form efficiently, whereas with AC this can be done with a simple and efficient transformer. This was the key to the success of the AC system. Modern transmission grids regularly use AC voltages up to 765,000 volts. ^[11] In physics, power (symbol: P) is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time. ... In electricity, current refers to electric current, which is the flow of electric charge. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ...

Alternating current transmission lines do have other losses not observed with direct current. Due to the skin effect, a conductor will have a higher resistance to alternating current than to direct current; the effect is measurable and of practical significance for large conductors carrying on the order of thousands of amperes. The increased resistance due to skin effect can be offset by changing the shape of conductors. The skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor so that the current density near the surface of the conductor is greater than that at its core. ...

Current Wars

Edison's publicity campaign

Edison carried out a campaign to discourage the use^[12] of alternating current, including spreading information on fatal AC accidents, killing animals, and lobbying against the use of AC in state legislatures. Edison directed his technicians, primarily Arthur Kennelly and Harold P. Brown,^[13] to preside over several AC-driven executions of animals, primarily stray cats and dogs but also unwanted cattle and horses. Acting on these directives, they were to demonstrate to the press that alternating current was more dangerous than Edison's system of direct current.^[14] Edison's series of animal executions peaked with the electrocution of Topsy the Elephant. He also tried to popularize the term for being electrocuted as being "Westinghoused". Fear, uncertainty, and doubt (FUD) is a sales or marketing strategy of disseminating negative (and vague) information on a competitors product. ... Arthur Edwin Kennelly (December 17, 1861 - June 18, 1939), was an American engineer in electricity. ... Harold P. Brown first invented the electric chair. ... The term electrocution can mean either: murder, accidental death or suicide by electric shock deliberate execution by electric shock, usually involving an electric chair; the word electrocution is a portmanteau for electrical execution The term is often used incorrectly to refer to a non-fatal event of electric shock. ... Topsy the Elephant (circa 1875 - January 4, 1903) was a member of a domesticated herd at Coney Islands Luna Park. ... The term electrocution can mean either: murder, accidental death or suicide by electric shock deliberate execution by electric shock, usually involving an electric chair; the word electrocution is a portmanteau for electrical execution The term is often used incorrectly to refer to a non-fatal event of electric shock. ...

Edison opposed capital punishment, but his desire to disparage the system of alternating current led to the invention of the electric chair. Harold P. Brown, who was at this time being secretly paid by Edison, constructed the first electric chair for the state of New York in order to promote the idea that alternating current was deadlier than DC.^[15] Capital punishment, or the death penalty, is the execution of a convicted criminal by the state as punishment for crimes known as capital crimes or capital offences. ... The electric chair is an execution method in which the person being put to death is strapped to a chair and electrocuted through electrodes placed on the body. ... Harold P. Brown first invented the electric chair. ... The electric chair is an execution method in which the person being put to death is strapped to a chair and electrocuted through electrodes placed on the body. ... This article is about the state. ...

When the chair was first used, on August 6, 1890, the technicians on hand misjudged the voltage needed to kill the condemned prisoner, William Kemmler. The first jolt of electricity was not enough to kill Kemmler, and left him only badly injured. The procedure had to be repeated and a reporter on hand described it as "an awful spectacle, far worse than hanging." George Westinghouse commented: "They would have done better using an axe." William Kemmler William Kemmler (May 9, 1860â€“ August 6, 1890) of Buffalo, New York was the first person to be executed via electric chair. ...

Niagara Falls

Experts announced proposals to harness Niagara Falls for generating electricity, even briefly considering compressed air as a power transmission medium. Against General Electric and Edison's proposal, Westinghouse, using Tesla's AC system, won the international Niagara Falls Commission contract. The commission was led by Lord Kelvin and backed by entrepreneurs such as J. P. Morgan, Lord Rothschild, and John Jacob Astor IV. Work began in 1893 on the Niagara Falls generation project and electric power at the Falls was generated and transmitted as alternating current. For other uses, see Niagara Falls (disambiguation). ... Pneumatics is the use of pressurized air to effect mechanical motion. ... Power transmission is the movement of energy from its place of generation to a location where it is applied to performing useful work. ... â€œGEâ€ redirects here. ... William Thomson, Archbishop of York, has the same name as this man. ... An entrepreneur (a loanword from French introduced and first defined by the Irish economist Richard Cantillon) is a person who operates a new enterprise or venture and assumes some accountability for the inherent risks. ... This article is about the financier. ... Baron Rothschild, of Tring in the County of Hertford, is a peerage title in the Peerage of the United Kingdom. ... John Jacob Astor IV (July 13, 1864 â€“ April 15, 1912) was an American millionaire businessman, inventor, writer, a member of the prominent Astor family, and a lieutenant colonel in the Spanish-American War. ...

Some doubted that the system would generate enough electricity to power industry in Buffalo. Tesla was sure it would work, saying that Niagara Falls had the ability to power the entire eastern U.S. Polyphase alternating current transmission had been previously demonstrated at Mill Creek California, and the Lauffen-Neckar demonstration in 1891. The Chicago World's Fair in 1893 exhibited a complete polyphase generation and distribution system installed by Westinghouse. However, none of the previous demonstration projects were on the scale of power available from Niagara. On November 16, 1896, electrical power was sent from Niagara Falls to industries in Buffalo from the hydroelectric generators at the Edward Dean Adams Station. The hydroelectric generators were built by Westinghouse Electric Corporation using Tesla's AC system patent. The nameplates on the generators bore Tesla's name. To appease the interests of General Electric, the contract to construct the transmission lines to Buffalo using the Tesla patents were given to them.^[16] Nickname: Location of Buffalo in New York State Coordinates: , Country State County Erie Government - Mayor Byron Brown (D) Area - City 52. ... is the 320th day of the year (321st in leap years) in the Gregorian calendar. ... Year 1896 (MDCCCXCVI) was a leap year starting on Wednesday (link will display calendar). ... For other uses, see Niagara Falls (disambiguation). ... Hydroelectric dam diagram The waters of Llyn Stwlan, the upper reservoir of the Ffestiniog Pumped-Storage Scheme in north Wales, can just be glimpsed on the right. ... Generator redirects here. ... For other uses, see Niagara Falls (disambiguation). ... Westinghouse logo (designed by Paul Rand) The Westinghouse Electric Company, headquartered in Monroeville, Pennsylvania, is an organization founded by George Westinghouse in 1886. ...

Competition outcome

AC replaced DC for central station power generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution. Edison's low-voltage distribution system using DC ultimately lost to AC devices proposed by others: primarily Tesla's polyphase systems, and also other contributors, such as Charles Proteus Steinmetz (in 1888, he was working in Pittsburgh for Westinghouse^[17]). Tesla's Niagara Falls system was a turning point in the acceptance of alternating current. Eventually, Edison's General Electric company converted to the AC system and began manufacture of AC machines. Centralized power generation became possible when it was recognized that alternating current electric power lines can transport electricity at low costs across great distances by taking advantage of the ability to transform the voltage using power transformers. Marconi Wireless Station in Somerset, New Jersey in 1921 Charles Proteus Steinmetz (April 9, 1865 â€“ October 26, 1923) was an American mathematician and electrical engineer. ...

Alternating current electricity distribution is today the penultimate stage in the delivery (before retail) of electricity to end users. It is generally considered to include medium-voltage (less than 50 kV) power lines, electrical substations and pole-mounted transformers, low-voltage (less than 1000 V) distribution wiring and sometimes electricity meters. Power transformers, installed at substations, could be used to raise the voltage from the generators and reduce it to supply loads. Increasing the voltage reduced the current in the transmission and distribution lines and hence the size of conductors required and distribution losses incurred. This made it more economical to distribute power over long distances. Generators (such as hydroelectric sites) could be located far from the loads. Electricity delivery is the process that goes from generation of electricity in the power central to the use by the consumer. ... Electricity retailing is the final process in the delivery of electricity from generation to the consumer. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... A 115 kV to 41. ... For other uses, see Transformer (disambiguation). ... Typical US domestic electricity meter An electric meter or energy meter is a device that measures the amount of electrical energy supplied to a residence or business. ... For other uses, see Transformer (disambiguation). ... A 115 kV to 41. ... Hydroelectric dam diagram The waters of Llyn Stwlan, the upper reservoir of the Ffestiniog Pumped-Storage Scheme in north Wales, can just be glimpsed on the right. ...

Alternating current transmission was simpler; the processes involved were recognized as easier, faster and less expensive to implement. This allowed the rapid deployment of bulk transfer systems for electrical power from place to place to bring about the electrification of America. Typically, the main power transmission was between the power plant and a substation near a populated area. Due to the large amount of power involved, the transmission normally took place at high voltage and was transmitted over long distances through overhead high tension lines. Underground power transmission was used only in densely populated areas (such as large cities) because of the high cost of installation and maintenance and because the power losses increase dramatically compared with overhead transmission. Underground high voltage transmission uses much lower voltages to avoid discharge to the surrounding ground, and lower voltages require much thicker wires unless superconductors and cryogenic technology are used. Alternating current power transmission system grids today provide redundant paths and lines for power routing from any power plant to any load center, via any possible route, based on the economics of the transmission path, the cost of power and the perceived importance of keeping a particular load center powered at all times. A transmission line is the material medium or structure that forms all or part of a path from one place to another for directing the transmission of energy, such as electromagnetic waves or acoustic waves, as well as electric power transmission. ... Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect. ...

Engineers today design alternating current transmission networks in such a way as to transport the energy as efficiently as possible while at the same time taking into account economic factors, network safety and redundancy. These networks use components such as power lines, cables, circuit breakers, switches and transformers. Power line redirects here. ... Look up redundancy in Wiktionary, the free dictionary. ... Power line redirects here. ... For other uses, see Cable (disambiguation). ... A 2 pole miniature circuit breaker A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. ... Electrical switches. ... For other uses, see Transformer (disambiguation). ...

Remnant and existent DC systems

Some cities retained their DC networks for varying periods of time. For example, central Helsinki had a DC network until the late 1940s, and Stockholm lost its diminishing DC network in the ´60s. A mercury arc valve rectifier station would convert AC for the downtown DC network. New York City's electric utility company, Consolidated Edison, continued to supply direct current to customers who had adopted it early in the twentieth century, mainly for elevators. In January 1998, Consolidated Edison started to eliminate DC service. At that time there were 4,600 DC customers. By 2006, there were only 60 customers using DC service, and on November 14, 2007, the last direct-current distribution by Con Edison was shut down ^[18] Location of Helsinki in Northern Europe Coordinates: , Country Province Region Uusimaa Sub-region Helsinki Charter 1550 Capital city 1812 Government - Mayor Jussi Pajunen Area - Total 187. ... A mercury arc valve (mercury vapor rectifier) is a type of electrical rectifier which converts alternating current into direct current. ... New York, New York and NYC redirect here. ... Consolidated Edison, Inc. ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s The 20th century lasted from 1901 to 2000 in the Gregorian calendar (often from (1900 to 1999 in common usage). ...

Electric railways that use a third-rail system generally employ high-current DC power between 500 and 750 volts; railways with overhead catenary lines use a number of power schemes including both high-voltage AC and high-current DC. Third rail at the West Falls Church Metro stop in Washington, D.C., electrified to 750 volts. ... The overhead lines of a Swiss Federal Railways track. ...

High voltage direct current (HVDC) systems are used for bulk transmission of energy from distant generating stations or for interconnection of separate alternating-current systems. These HVDC systems use solid state devices that were unavailable during the War of Currents era. Power is still converted to and from alternating current at each side of the modern HVDC link. The advantages of present HVDC over historic AC systems for bulk transmission include higher power ratings for a given line (important since installing new lines and even upgrading old ones is extremely expensive) and better control of power flows, especially in transient and emergency conditions that can often lead to blackouts. HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ... HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ... In electronics, solid state circuits are those that do not contain vacuum tubes. ...

While direct current power distribution systems for transmission of power at utilization voltage over significant distances is essentially extinct, use of DC power is still common when transmission distances are small, and especially when energy storage or conversion uses batteries or fuel cells. These applications include:

In these applications, direct current may be used directly or converted to alternating current using power electronic devices either for use by local AC equipment or for energy transmission by the AC distribution and transmission network. In the future this may provide a way to supply energy to a grid from distributed sources that many not inherently supply energy in the form of alternating current. For example, hybrid vehicle owners may rent the capacity of their vehicle's batteries for load-levelling purposes by the local electrical utility company. Lead-acid car battery A car battery is a type of rechargeable battery that supplies electric energy to an automobile[1]. Usually this refers to a SLI battery (Starting - Lighting - Ignition) to power the starter motor, the lights and the ignition system of a vehicleâ€™s engine. ... A Chevy Volt, one example of a plug-in hybrid electric vehicle, expected to set a new benchmark. ... For other uses, see Telephone (disambiguation). ... An uninterruptible power supply (UPS), also known as an uninterruptible power source or a battery backup is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available. ... Ffestiniog pumped storage power station upper reservoir Grid energy storage lets energy producers send excess electricity over the electricity transmission grid to temporary electricity storage sites that become energy producers when electricity demand is greater. ... An inverter may be: inverter (electrical), which converts direct current (DC) to alternating current (AC) inverter (logic gate), also called a NOT gate. ...

In popular culture

The Prestige is a 2006 period film directed by Christopher Nolan, with a screenplay adapted from the 1995 World Fantasy Award-winning novel of the same name by Christopher Priest. ... Tesla is the name of an American rock band originating in Sacramento, California. ... Psychotic Supper is the third studio album from the rock band Tesla. ... The Devil in the White City: Murder, Magic and Madness at the Fair that Changed America is a 2003 book by Erik Larson. ...

Contents

Introduction

Electric power transmission

The competing systems

Early transmission analysis

Transmission loss

Current Wars

Edison's publicity campaign

Niagara Falls

Competition outcome

Remnant and existent DC systems

In popular culture

See also

References and articles

Contents

Introduction GA_googleFillSlot("encyclopedia_square");

Electric power transmission

The competing systems

Early transmission analysis

Transmission loss

Current Wars

Edison's publicity campaign

Niagara Falls

Competition outcome

Remnant and existent DC systems

In popular culture

See also

References and articles

Introduction