Poul la Cour (13 April 1846 – 24 April 1908) was a
Danish
Danish may refer to:
* Something of, from, or related to the country of Denmark
People
* A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark
* Culture of Denmark
* Danish people or Danes, people with a Danish a ...
scientist, inventor and educationalist. Today la Cour is especially recognized for his early work on
wind power
Wind power or wind energy is mostly the use of wind turbines to generate electricity. Wind power is a popular, sustainable, renewable energy source that has a much smaller impact on the environment than burning fossil fuels. Historically ...
, both experimental work on aerodynamics and practical implementation of wind power plants. He worked most of his life at Askov Folk High School where he developed the historic genetic method of teaching the sciences. Early in his life he was a telegraphic inventor working with multiplex telegraphy.
Biography
Poul la Cour was born on 13 April 1846 on a farm near
Ebeltoft
Ebeltoft is an old port town on the central east coast of Denmark with a population of 7,204 (1 January 2022).[Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of Denmark
, establish ...](_blank)
. His father was a modern farmer introducing new technology at his farm as the first among neighbours. However la Cour had his gifts in mathematics from his mother. At Latin school in
Randers
Randers () is a city in Randers Municipality, Central Denmark Region on the Jutland peninsula. It is Denmark's sixth-largest city, with a population of 62,802 (as of 1 January 2022).[meteorology
Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did no ...]
.
Telegraphic inventor
After having finished his studies in physics and meteorology in Copenhagen in 1869 Poul la Cour travelled in Europe to study practical meteorology. He received his most important inspiration from the Dutch meteorologist de Buijs Ballot, with whom he spent a month. He became convinced that Denmark should set up a planned meteorological institute according to the principles of de Buijs Ballot. During the next five years his life was closely interwoven with the early history of the Danish Meteorological Institute, which was founded in 1872 with him as a Deputy Director.
Telegraphy
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas ...
, the most important technological prerequisite for modern meteorology, soon became his main interest. In June 1874, the year in which
Edison invented his quadruplex telegraphy, la Cour invented a telegraphic device based on tuning forks. The idea was to permit a number of telegraphers to send messages on a single wire, each using his own frequency. By using the resonance phenomenon of tuning forks it was possible to split out the messages at the receiving end of the wire. He patented his invention in London on 2 September 1874, but in the United States
Alexander Graham Bell,
Elisha Gray and others had been working along similar lines, which resulted in protests against his American patent applications. Having too little money to pay lawyers, he gave up his claim in America, and this invention was credited to Elisha Gray. La Cour however maintained that Gray had been working on the invention of the
telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...
, and only had changed his invention at the instant la Cour's American application was published. La Cour later wrote in an autobiographical article that he felt some malicious pleasure when Graham Bell was awarded the telephone patent by applying only a few hours before Gray.
In 1876 la Cour could demonstrate 12-fold telegraphy with his system, and the Great Nordic Telegraph Company was interested in it for some time. However, only the Danish Railroad Company seems to have used his invention in Denmark. After the disappointment on the American market, he produced a new invention, the phonic wheel – a
synchronous motor
A synchronous electric motor is an AC electric motor in which, at steady state,
the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles. Syn ...
driven by a
tuning fork
A tuning fork is an acoustic resonator in the form of a two-pronged fork with the prongs ( tines) formed from a U-shaped bar of elastic metal (usually steel). It resonates at a specific constant pitch when set vibrating by striking it agains ...
, which used an
electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in ...
to rotate the cogwheel of the motor by one tooth for each vibration. With two synchronous phonic wheels at a distance, a multitude of telegraphic devices was possible. This time there were no problems with the patent. The invention was produced in August 1875, patented in 1877, and the details were published in the book ''The Phonic Wheel'' in 1878 in a Danish and a French edition. At that time the invention was adopted by the American company The Delany Synchronous multiple Telegraph, and a new fight of priority arose. In 1886 the
Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...
awarded la Cour the
John Scott Legacy Medal for the phonic wheel and at the same time presented Delany with the
Elliott Cresson Medal for the synchronism, a decision la Cour protested against.
The phonic wheel was used (in the form of Delany's multiplex telegraphy) on some telegraph lines on the
East Coast of the US, and in the London Post Office. It was used as a
chronometer
A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and th ...
, which was accurate to 0.00004 seconds in short time measurements. The most modern application was in the mechanical "television" of
Paul Gottlieb Nipkow
Paul Julius Gottlieb Nipkow (22 August 1860 – 24 August 1940) was a German technician and inventor. He invented the Nipkow disk, which laid the foundation of television, since his disk was a fundamental component in the first televisions. ...
(1884).
The experimental mill at Askov 1891
During the 1880s there had been some criticism of the Grundtvigian historical approach in the Folk High Schools. In particular, the use of Nordic myths and realism gained a stronger position in Askov Højskole.
La Cour's historical approach was not criticized much, but he also reread his Grundtvig and claimed that "in fact it is an indication of the power of history that I creates life (now)". In the 1890s la Cour and
Askov Folk High School became more concerned with material reality, in teaching as well as in action.
La Cour again became an inventor and experimental physicist, working for the benefit of the rural areas, form where most of the students came. Denmark is blessed with a lot of wind, and at a time where electricity was about to be introduced in Denmark, la Cour felt that the wind should contribute to the electrification of the country. In the
Netherlands
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, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
, the idea of electrification by means of windmills had been investigated with negative conclusions, because of their low efficiency, and the problems of storing energy . But these problems had appealed to the inventor and physicist la Cour. In 1891 he got the idea of storing wind as hydrogen (and oxygen) energy by passing the electricity through water and using
electrolysis.
He was granted financial support by the Danish Government, and the first experimental mill at Askov was erected in the summer of 1891. La Cour's first task however was to "tame" the wind power, in order to make the mill produce a constant power in order to drive a generator. This was solved by the so-called Kratostate, a differential regulator, which later was simplified ("vippeforlaget") and widely used in electricity producing windmills in the
Nordic countries and
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
.
Electrochemical experiments
With assistance from professor Pompeo Garuti of Italy he was able to develop the hydrogen storage system in a few years. Because of his personal contributions to this technology he was granted a monopoly of using Garutis patents in Denmark. From 1895 until 1902 Askov Folk High School was illuminated by a mixture of
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
and
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
, and although the energy originated from the wind, there does not seem to have been a single day without light, thanks to the 12 cubic metres hydrogen tank.
The reason why la Cour abandoned this system in 1902 was that he failed to develop a gas engine based on hydrogen as a fuel, although years were spent on experiments. With such a motor electricity could be reproduced, and la Cour soon realized that electricity was the energy medium of the future. He then tried other forms electrochemical energy storage, the idea being to develop prototypes of small cottage industry: from limestone and coal he produced
Calcium carbide
Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of Ca C2. Its main use industrially is in the production of acetylene and calcium cyanamide.
The pure material is colorless, while pieces of te ...
according to the process of Thomas L Willson and from salt he produced soda lye,
sodium hydroxide. This did not turn into cottage industries but gave rise to some small Danish companies "Dansk Acetylen gasværk" og "Dansk elektrolytisk Alkalindustri". His last electrochemical idea was the small scale production of artificial fertilizer using the process just invented by the Norwegians,
Kristian Birkeland
Kristian Olaf Bernhard Birkeland (13 December 1867 – 15 June 1917) was a Norwegian scientist. He is best remembered for his theories of atmospheric electric currents that elucidated the nature of the aurora borealis. In order to fund his res ...
and
Sam Eyde
Samuel Eyde (29 October 1866 – 21 June 1940) was a Norwegian engineer and industrialist. He was the founder of both Norsk Hydro and Elkem.
Personal life
Eyde was born in Arendal in Aust-Agder, Norway. He was a son of ship-owner Samuel Eyde (181 ...
.
![Poul la Cour Museet 01](https://upload.wikimedia.org/wikipedia/commons/2/2d/Poul_la_Cour_Museet_01.jpg)
Experiments in aerodynamics 1896–1900
The classical windmills should be able to rotate in a gentle breeze, but the traditional miller was not able to utilize the huge amount of energy in a storm. For la Cour the
windmill
A windmill is a structure that converts wind power into rotational energy using vanes called sails or blades, specifically to mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and other applications, in some ...
was a
power plant
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an el ...
, which should produce a maximum of energy. Therefore, the traditional windmill had to be changed, and that was the background for his experiments in aerodynamics starting in 1896.
Traditional wisdom considered the action of wind on the wings as an impulse of particles, which made
Newtonian calculations possible. Although
Daniel Bernoulli and
Leonhard Euler
Leonhard Euler ( , ; 15 April 170718 September 1783) was a Swiss mathematician, physicist, astronomer, geographer, logician and engineer who founded the studies of graph theory and topology and made pioneering and influential discoveries in ma ...
had laid the foundation of modern
fluid dynamics a hundred years earlier this had had no consequence for such complicated practical problems as that of the action of wind on wings; and in the cases where a computation was possible, theory did not match experience (Paradox of d'Alembert). The union of theory and experiment came mainly through careful
wind tunnel
Wind tunnels are large tubes with air blowing through them which are used to replicate the interaction between air and an object flying through the air or moving along the ground. Researchers use wind tunnels to learn more about how an aircraft ...
experiments. The Danish tradition in this area was started by H. C. Vogt and Johan Irminger in the early 1890s. La Cour continued in 1896 when he started to test small models of windmills in a wind tunnel, probably the first such experiments in the world focusing on windmills.
After only a few weeks of experiments la Cour came to the general conclusions that are still accepted: to produce a maximum of energy with a given wing area, the number of wings should be small, their bevel small and the speed of rotation fast. A few years later he presented his results to an audience of engineers: working with the a standard size wing he found that under optimal conditions 8 wings would absorb 28% of the total energy passing swept area, and 16 wings only slightly better (29%), and even 4 wings were fairly good (21%). In a calculation based on the particle conception of wind, he found that the four wings could absorb 144% of the energy which struck them, which of course is impossible. He concluded that in general all former theories and formulae concerning wings seemed to be incorrect; and to the extent they were correct, gave no information of any practical importance to the millwright.
A closer examination of the quality of la Cour's wind tunnel shows that the wind speed varies with a factor 2 form the centre line to the edge, thus putting some inaccuracy to his results. He was probably aware of this defect, for throughout 1899 he was very careful in the experimental setup. He now worked with small wing sections, flat and curved plates, in the middle of the wind tunnel, and measured both size and direction of the resulting force, thereby discovering the advantages of curved profiles. His curved wing could produce a factor 3 better than the flat wing if there was not too much air resistance to take into account.
Based on these experiments he suggested an ideal mill with four times the effect (per wing area) of the average of five existing mills which he had measured. When he actually in 1899 built a new mill in Askov it was only twice as effective, because of a 7% resistance area. In 1929, only twenty years after la Cour's death, a new Askov mill was built directly according to la Cour's "ideal" and this time the factor 4 was obtained. For comparison, windmills today are about 3 times as effective as the 1929 mill. Needless to say there are some assumptions and problems with all these comparisons, but they do indicate that an important step forward was made by la Cour.
Popular technical enlightenment
The fact that la Cour's ideal mill looked very much like the traditional Dutch windmill resulted in some criticism of his work, and government support was reduced in 1902. But by that time most of the experimental work had been completed and published, and he only considered these experiments a means to his goal which was the development of the rural areas in Denmark. It thus happened that in 1902 the windmill in Askov became a prototype electrical power plant serving the village of Askov until 1958 with batteries for energy storage and a petrol-engine for reserve power.
At the same time la Cour started to propagate the idea of wind electricity. If people in a city or a village planned a power plant, la Cour was often invited to explain the advantages of this new energy source. He even wrote a fairy tale, "
Trolden" (the troll), about energy for children, and there was no doubt that electricity was the hero in that fairy tale.
The most important means of propagating wind electricity was the Danish Wind Electricity Society (DVES) initiated by la Cour in 1903. For the next five years, the consultant engineer of DVES planned a hundred small electricity power-plants, a third of these being based on wind power.
Just as important for rural electricity was the training of rural electricians. DVES instructed about 20 electricians a year in Askov. They learned theory for three months with the maintenance and development of the Askov wind power plant as a parallel practical experience. They finished with a project building a small power plant somewhere in Denmark. This was a short training period compared to the 4 years of the city
electrician
An electrician is a tradesperson specializing in electrical wiring of buildings, transmission lines, stationary machines, and related equipment. Electricians may be employed in the installation of new electrical components or the maintenance ...
, but an investigation of their later careers shows that most of them found jobs as rural electricians – many as managers of small power plants.
Finally DVES published a bimonthly journal on wind electricity with la Cour as the author of most of the articles. Comparing this total activity with the actual number of small rural electric power plants built in Denmark in the beginning of the century one must conclude that DVES was one of the most important factors in the unique decentralized electrification in Denmark.
Poul la Cour Prize
In 1992, in recognition of Poul la Cour's pioneering work in wind energy technology, the European Wind Energy Association, now known as Wind Europe, established the Poul la Cour Prize
for outstanding contributions to the wind energy industry.
Winners
* 1993 Erik Grove Nielsen - Aerostar for pioneering blade design
* 1995
Aloys Wobben
Aloys Wobben (22 January 1952 – 31 July 2021) was a German billionaire businessman, engineer, and the founder and owner of the wind turbine company Enercon. He was one of the 50 richest people in Germany, with a fortune estimated at €4.78 bi ...
- Enercon for the gearless ENERCON turbine
* 1999 Søren Krohn - Danish Wind Industry Association - for www.windpower.org
* 2001 Ecotecnica for their co-operative organisation structure
* 2003 Wolfgang Palz - EC for his work at the European Commission
* 2004 Esteban Morras - EHN for establishing EHN as one of the leading renewable energy developers in the world
* 2006
Andrew Garrad - Garrad Hassan for outstanding personal achievement in wind energy
* 2007 Erik Lundtang Petersen - Risø in honour of outstanding achievements in wind energy and for his scientific integrity
* 2008 Jos Beurskens - Energy Research Centre of the Netherlands (ECN) for his outstanding achievements and many years’ service in the field of wind energy
* 2009 Mechtild Rothe - MEP for her commitment to promoting renewable energy in Europe
* 2010 Ian Mays RES - CEO and founder of one of the foremost contributors to the development of wind energy on the international stage
* 2011 Heinrik Stiesdal - Siemens Chief Technology Officer at Siemens Wind Power.
* 2012 Christian Nath Germanischer Lloyd (GL).German classification society
* 2013 Professor Arthouros Zervos - EWEA President (2001 - 2013)
* 2014
Eddie O'Connor - Mainstream Renewable Power's founder and CEO
* 2019 John T Olesen - GE Renewables, for outstanding contribution to wind energy technology
* 2021 Anne Velenturf - University of Leeds, for her contribution to circular economy for sustainable wind industry development
Patents
* Elektriske Telegrafapparater. Danish Patent no. 41, 1875
* Obtaining synchronous Movements. English Patent no. 4779, 1882.
* Fremgangsmåde til Spektrotelegrafi, samt dertilhørende Apparater. Danish Patent no. 193, 1890.
* Apparat til at bringe en motor til automatisk at følge en af samme uafhængig bevæget Mekanisme. Danish Patent no. 1068, 1892
* Fremgangsmåde og Anordning til Formering og Udvaskning af Kviksølvkatoder under ensartede Betingelser. Danish Patent no. 5048, 1902.
* Automatisk Reguleringsmetode for en elektrisk Strøm fra en Ligestrømsdynamo til et Akkumulatorbatteri med dertil hørende Ledningsnet. Danish patent no. 6138, 1903. English patent no. 131, 1904.
References
* Arnfred, J. Th. (1968): Poul la Cour som opfinder. Årbog for Danmarks Tekniske Museum.
* Dresing, P. C. (1887): The invention of synchronous rotations by means of Poul la Cours phonic wheel as used in telegraphy. Electrical Review 14 January 1887, pp. 31f.
* Hansen, Hans Christian (1985): Poul la Cour, grundtvigianer, opfinder og folkeoplyser. Doctoral thesis in Danish with an English summary
Extract* Hansen, Hans Christian (1981): Forsøgsmøllen i Askov.
* van Heurn, J. (1894): Electrische Beweegkracht verkregen door Windmolens. Amsterdam.
* la Cour, L. F. (1917): Slægten la Cour.
* la Cour, Poul (1887): The Phonic Wheel. In electrical Review 25 November 1887.
* la Cour, Poul( 1900): Forsøgsmøllen i Askov I-II,
* Nissen, Povl-Otto (2003): Poul la Cour og vindmøllerne.
* Report of the Special Committee appointed to investigate the protest of Poul la Cour... Journal of the Franklin Institute, August 1887.
External links
* Lyngsø-Petersen, Erik.
Poul la Cour og hans tid ''
Ingeniøren
''Ingeniøren'' (full name: ''Nyhedsmagasinet Ingeniøren'', literally ''The News Magazine "The Engineer"'') is a Danish weekly newspaper specialising in engineering topics.
History and profile
The paper has covered science and technology issues ...
'', 6 September 1985
{{DEFAULTSORT:La Cour, Poul
1846 births
1908 deaths
People from Ebeltoft
Danish physicists
People associated with wind power
19th-century Danish inventors
Danish meteorologists