History of Alternating Current:
AC Power History and Timeline
current power drives our world today. AC power was the next logical
step after DC power was established. The founders, developers, and visionaries
of AC power are depicted below. Click on the pioneer to learn more,
or see the list below.
The inventors, including the first year they developed the technology
or improved the technology (most
continued to improve the technology after that date, it was rarely a
one time achievement)
Stanley and Thomson had worked on motor, but it had a commutator.
Ferraris invented an AC three phase motor without commutator. Tesla
and Oliver Shallenberger also were working on the motor a couple of
months behind Ferraris.
To learn about
important early sites and installations of AC power please see our History
of Power Transmission and Electrification page:
Power Development Timeline:
- Hippolyte Pixii builds the first alternator. Pixii builds
a device with a rotating magnet. He doesn't know how to make his creation
useful since all the other experimenters of the time were building
DC devices. Others like Faraday and Henry were experimenting at the
time with primitive electric motors using electromagnets.
1855 - Guillaume Duchenne uses alternating current in electrotherapeutic
triggering of muscle contractions. (Paris, France) AC
power is not viewed as useful for anything else at the time.
1878 - Ganz Company starts working with single phase AC power
systems in Budapest, Austro-Hungary
- London: Walter Baily makes a copper disc rotate using alternating
current (this is a weak early AC motor) which was not effective for
bearing any load.
This decade proved to be an exciting time for the development of electric
power, read below to find out some of the major developments by year.
Sabastian Ferranti (Englishman with an Italian parent) works
at Siemens Brothers firm in London with Lord Kelvin (William
Thompson), and Ince. With the help of Lord Kelvin Ferranti pioneers
early AC power technology, including an early transformer.
Later on John Gibbs and Lucien Gaulard would base their designs off
1884 - Turin, Italy: Lucien Gaulard develops transformers
and the power transmission system from Lanzo to Turino. The demonstration
of AC power includes a 25 mile trolley with step down transformers
that allow low power Edison incandescent lights to light the path
along with arc lamps. Galileo Ferraris
was head of the Electrical Department. The next year Ferraris would
invent the polyphase motor.
1885 - Ferraris conceives the idea of the first polyphase AC
motor: " In the summer of 1885 he conceived the idea that two
out-of-phase, but synchronized, currents might be used to produce
two magnetic fields that could be combined to produce a rotating field
without any need for switching or for moving parts. "
- Elihu Thomson at Thomson-Houston starts
experimenting with AC power (the first company in the US to start
work on AC)
- George Westinghouse is intrigued by AC power and buys North American
rights to Gaulard and Gibbs system for $50,000
- George Westinghouse orders a Siemens alternator (AC generator)
and a Gaulard and Gibbs transformer. Stanley begin experimenting with
An important year for AC power
- Great Barrington, Massachusetts
- the first full AC power system in the world is demonstrated
using step up and step down transformers. The system was built by
William Stanley and funded by Westinghouse.
1886 - November - Buffalo, New York receives the first commercial
AC power system in the USA. This system designed by George Westinghouse,
William Stanley, and Oliver
- William Stanley designs an improved version of the Siemens single
1886 - Fall - Elihu Thomson's AC
power system is rejected by the patent office. Westinghouse is already
far ahead, having sold its system commercially already.
- Nikola Tesla tries to sell his AC power system to investors in New
York City, but it fails to be of interest in a city which is already
heavily invested in DC power systems. Other inventors around the world
also promoting AC power have similar problems. This is especially
due to the fact that no one has yet to invent an AC electric motor
which is efficient.
- Otto Blathy comes to the USA and Thomas Edison buys options
on the Z.B.D. Transformer. This would
put him in the position to rival Westinghouse that controlled the
Gaulard and Gibbs transformer patent. Later Edison decides that it
is not worth going into AC and drops his options on the Z.B.D. Transformer.
- C.S. Bradley builds the first AC 3 phase generator.
Up until this time Siemens and Westinghouse had been producing single
phase AC generators. The 3 phase system would be a great improvement.
- F. Augus Haselwander develops the first AC
3 phase generator in Europe. He is behind Bradley by a couple
months and it is generally believed that he built his design independently
- Sabastian Ferranti designs Depford Power Station in London.
When it is completed in 1891 it would be an important early site in
AC power history.
- Mikhail Dolivo-Dobrovsky in Germany builts his first AC polyphase
generator. He works for AEG. (Allgemeine Elektricitäts-Gesellschaft)l
1888 - April - Galileo Ferraris
makes public his AC polyphase motor first conceived in 1885. His motor
works without a commutator, this development finally makes the AC
motor efficient, and therefore competitive with DC motors. The A motor
report was first published at the Royal Academy of Sciences in Turin.
Westinghouse read the report of Ferraris and saw a chance for AC systems
to become much more marketable
1888 - May 15 - Tesla
stands before the AIEE showing his polyphase motor. Elihu Thomson
was there and some in the group seemed to be impressed. One week later
Westinghouse sent out a recruiter to get Tesla to join him. Tesla's
progress on the motor is slightly ahead of Oliver Shallenberger's
3 phase electric motor. Shallenberger
was already working for Westinghouse.
Tesla claims he "dreamed up" the first polyphase motor before
Galileo Ferraris. Later
at a trial a US court sides
with Tesla despite the fact that Tesla has no proof besides witness
testimony.Read more here
1889 - Dobrovolsky builds his first transformer and motor to
work with his 3 phase AC system
- Frankfurt, Germany: First distance
power transmission (for electric power utility) Lauffen to
Frankfurt 109 miles. The entire system was designed by Dobrovsky from
generator to electric motor. Many important figures of AC power were
invited to the event, at the Congress Dinner Galileo
Ferraris was hailed as the father of three-phase current.
- Charles P. Steinmetz
goes before the AIEE and presents his paper on hysteresis, or the
delay effect in 3 phase AC power. Steinmetz was the first person to
understand AC power from a mathematical point of view. After his paper
he is hired by General Electric Company and joins forces with Elihu
Thomson and William Stanley. Steinmetz would go on to improve and
troubleshoot future AC power systems.
1893 - Redlands
Power House - the first commercial installation of 3 phase AC
power, 40 hz.
1895 - Folsom
Power House - The first installation of modern AC power in
the USA: 3 Phase AC at 60 Hz.
1895 - Westinghouse builds the power system for the Adams
Power Station at Niagara Falls. Benjamin Garver Lamme
is the principal engineer of the operation. General Electric builds
the 25 mile power transmission system from the Niagara power house
to Buffalo, NY which is made operational in 1896.
1897 - Mechanicville Power Station
- Charles P. Steinmetz experiments with a unique single phase AC power
1900s - Three Phase AC power is fully established as the principle
source of power for the world
From the perspective of historian Joesph Cunningham:
The development of electrical
systems is a long and winding story which I have been researching
for some 48 years. From the arc light systems, now forgotten,
which played a major role; to the incandescent light systems
of Edison and his competitors; through the development of
power systems in the 20th century, much has been lost or forgotten.
For example, the DC transmission concepts of Rene Thury are
all but gone from most reference sources, as are those of
later HVDC pioneers.
When it comes to polyphase AC, it appears that there is no
true "father," but rather a number of researchers.
William Stanley, the inventor
of the transformer in the US was funded by George Westinghouse,
an industrialist in railway air brake and signal systems who
sought to improve upon the limitations of the DC systems.
In Germany, Werner
Siemens and others took the lead and produced the first
long distance transmission of AC power 1891. AC motors were
a different matter and the two leading figures on opposite
sides of the Atlantic approached the problem independently.
Galileo Ferraris, a physicist
at the university of Turin, described in 1885 the rotating
field principle. but did not publish until 1888 by which time
Nikola Tesla, having conceived the concept as well, had built
machines for which patents were granted two weeks after the
Ferraris publication. Tesla, seeking commercial development
of an AC motor, developed a two phase system of supply. Tesla
in a letter to Electrical World of May 25, 1889 recognized
Ferraris' work and also cited the work of Oliver Shallenberger
at Westinghouse. Shallenberger claimed to have intuited the
principle after the observation of the twisting of a meter
spring in the field of an AC coil. Electrical World of April
15, 1893 attempted to sort this issue by giving field theory
primacy to Ferraris and
multiphase system primacy to Tesla. Many, including Thomas
Hughes in his book Networks of Power (Johns Hopkins U Press
available from Amazon) believe that the issue of primacy
of the idea will never be settled completely.
The Tesla system patents, though two phase, were the basis
of the Westinghouse system at the Columbian Exposition and
then at Niagara Falls. At the time, Tesla's work was the most
recognized, having been the subject of demonstrations to the
AIEE (now IEEE) and also at Columbia University and having
undergone a thorough analysis by Prof. Anthony, director of
the electrical engineering program at Cornell. Tesla was subsequently
feted by the science academies of London and Paris.
Elihu Thomson of Thomson-Houston
arrived at AC by another path. He produced initially AC arc
light systems and formed the basis for the GE effort directed
by Steinmetz, for GE was an amalgamation of Edison and Sprague
companies funded through T-H capital. An article in the IEEE
PES from several years ago detailed the birth of 3 phase systems
through both AEG and Siemens efforts. In the United States,
transmission range was a paramount concern and two phase systems
prevailed for several decades whereever AC was supplied to
the customer, thus the Tesla/Westinghouse system found a ready
phase customer connections were not common until the 1920s;
acceptance delayed by an inability to balance single phase
customer loads on three phase AC lines. Only after the work
of Charles Fortescu at Westinghouse and also that of Edith
Clark at GE in the 1917-20 period were standardized equations
available for the engineering of three phase distribution.
As for other AC pioneers there are many - Frank
Sprague, usually associated with railways, was an early
proponent of AC research. Having the mathematical skills to
devise the practical formulae to adapt the British Hopkinson
3 wire system to Edison lighting applications, he went on
to develop practical industrial motors which made small utility
companies financially viable with the establishment of a daytime
motor load. As consultant to the Edison company in NY he recommended
the use of AC in a large central plant to be distributed through
"receiving" stations in which a transformer would
step down the voltage and apply it to a "receiving motor"
(reversed alternator) to drive DC generators. That report
in September ,1886, but a few months after the first Stanley
installation in Great Barrington, shows how universal
was the thinking toward large scale AC generation. In that
sense, the conversion substation could be said to have been
invented by Sprague.
Thus the story has many participants, most of whom replicated
another's work, sometimes simultaneously, often with no knowledge
of the other. Even the standard power converter of the day
had multiple fathers. Benjamin Lamme who led development
of AC at Westinghouse described his rotary converter as the
overlaying of a DC generator on a synchronous motor and believed
it unique until he discovered that Charles Bradley
(Bradley Electric was later acquired by of GE) had applied
for a patent as well and there are indications that others
had the same idea.
Much of the AC distribution refinement which led to the practical
secondary distribution network was the work of Westinghouse
engineers working with the United Electric Light & Power
Co. in Manhattan to develop the first practical AC networks.
But even at Westinghouse, it was researchers like Guido
Pantaleoni, a student of Ferraris, that bridged the ocean
by licensing the Gaulard and Gibbs, Siemens, and AEG patents.
Sebastian Zinni DeFerrante, a leader in British arc
lighting while still in his mid teens, had installed underground
10,000 volt lines in London as early as 1891.
Moreover, in an era prior to the refined understanding
of inductance, capacitance and reactive power issues, and
prior to the development of steel with magnetic characteristics
ideal for alternating fields, the issue of the best frequency
was another major concern. Benjamin Lamme's article on the
Technical Story of the Frequencies (presented Jan 1918 to
the Washington Section AIEE and available online under Google
Books) is the best source of 1890s thinking on the issues.
Joseph Cunningham has contributed information for television
programs and technical publications.
See more of his articles on the IEEE
website. (IEEE membership may be required to view some
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The Power Makers: Steam, Electricity, and the Men who Invented Modern
Networks of Power: Electrification in Western Society, 1880-1930 by
Thomas Parke Hughes
Galileo Ferraris Biography.
Wikipedia: Benjamin G. Lamme,
Rochester Historical Society
Great Barrington Historical Society
Workshop of Engineers. John Miller. 1953
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