Misplaced Pages

#552447

151-399: Electricity became a subject of scientific interest in the late 17th century. Over the next two centuries a number of important discoveries were made including the incandescent light bulb and the voltaic pile . Probably the greatest discovery with respect to power engineering came from Michael Faraday who in 1831 discovered that a change in magnetic flux induces an electromotive force in

302-455: A conductor 's surface, since otherwise there would be a force along the surface of the conductor that would move the charge carriers to even the potential across the surface. The electric field was formally defined as the force exerted per unit charge, but the concept of potential allows for a more useful and equivalent definition: the electric field is the local gradient of the electric potential. Usually expressed in volts per metre,

453-461: A force on each other, an effect that was known, though not understood, in antiquity. A lightweight ball suspended by a fine thread can be charged by touching it with a glass rod that has itself been charged by rubbing with a cloth. If a similar ball is charged by the same glass rod, it is found to repel the first: the charge acts to force the two balls apart. Two balls that are charged with a rubbed amber rod also repel each other. However, if one ball

604-409: A steady state current, but instead blocks it. The inductor is a conductor, usually a coil of wire, that stores energy in a magnetic field in response to the current through it. When the current changes, the magnetic field does too, inducing a voltage between the ends of the conductor. The induced voltage is proportional to the time rate of change of the current. The constant of proportionality

755-432: A charge of Q coulombs every t seconds passing through an electric potential ( voltage ) difference of V is where Electric power is generally supplied to businesses and homes by the electric power industry . Electricity is usually sold by the kilowatt hour (3.6 MJ) which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using electricity meters , which keep

906-512: A common reference point to which potentials may be expressed and compared is useful. While this could be at infinity, a much more useful reference is the Earth itself, which is assumed to be at the same potential everywhere. This reference point naturally takes the name earth or ground . Earth is assumed to be an infinite source of equal amounts of positive and negative charge and is therefore electrically uncharged—and unchargeable. Electric potential

1057-591: A complete list, together with links, is published on the town's website at [2] Lauffen am Neckar was the birthplace of alternating current transmission. For the International Electro-Technical Exhibition - 1891 in Frankfurt am Main , Dolivo-Dobrowolsky and Oskar von Miller constructed a three-phase high-voltage transmission line which came into operation on 24 August 1891. For this, a three-phase alternator made by Maschinenfabrik Oerlikon

1208-433: A crossing point. Such opportunities were few and far between along this stretch of the original Neckar. Indeed, the nearest fords were some kilometres distant. The two prominent cliffs may well have served as lookouts and refuges since primeval times. The foundations of a Roman estate (Villa Rustica) dating from between the 2nd and 3rd centuries, along with coins and pottery, were discovered some two kilometres (1.2 miles) to

1359-468: A current of one amp. The capacitor is a development of the Leyden jar and is a device that can store charge, and thereby storing electrical energy in the resulting field. It consists of two conducting plates separated by a thin insulating dielectric layer; in practice, thin metal foils are coiled together, increasing the surface area per unit volume and therefore the capacitance . The unit of capacitance

1510-490: A dampened kite string and flown the kite in a storm-threatened sky . A succession of sparks jumping from the key to the back of his hand showed that lightning was indeed electrical in nature. He also explained the apparently paradoxical behavior of the Leyden jar as a device for storing large amounts of electrical charge in terms of electricity consisting of both positive and negative charges. In 1775, Hugh Williamson reported

1661-569: A great bow – an event which is estimated to have taken place between 400 BC and 100 BC. In 832 Emperor Ludwig Louis the Pious granted the then unfortified village to his son-in-law Ernst, the margrave of Nordgau in the Upper Palatinate , on condition that the inhospitable place be suitably developed – it was the property of the Emperor, who intended to use it for hunting. The initial cultivation of

SECTION 10

#1733106666553

1812-640: A large force belonging to Wilhelm, Duke of Saxe-Weimar and George Frederick, Margrave of Brandenburg-Ansbach assembled at the bridge to engage the imperial troops. Battle was joined at Wimpfen early in May and resulted in victory for the imperial forces. After this defeat, two companies of the Margrave's troops and many Neckargartach farmers took refuge in Lauffen. The town was spared major fighting for several years, but almost 20 years of suffering were still to come. In 1629,

1963-474: A large force of imperial troops moved through the town, to be followed in 1631 by troops of Lorraine . In 1634, Croatian soldiers plundered Lauffen and two days later the imperial forces returned. In November the last 16 head of cattle were confiscated. At Christmas 1634, Lauffen provided winter quarters for five transiting regiments. At Whitsun 1635, the Mühlheimische Kürassier-Regiment seized

2114-425: A large lightning cloud may be as high as 100 MV and have discharge energies as great as 250 kWh. The field strength is greatly affected by nearby conducting objects, and it is particularly intense when it is forced to curve around sharply pointed objects. This principle is exploited in the lightning conductor , the sharp spike of which acts to encourage the lightning strike to develop there, rather than to

2265-467: A loop of wire—a principle known as electromagnetic induction that helps explain how generators and transformers work. In 1881 two electricians built the world's first power station at Godalming in England. The station employed two waterwheels to produce an alternating current that was used to supply seven Siemens arc lamps at 250 volts and thirty-four incandescent lamps at 40 volts. However supply

2416-402: A millimetre per second, the electric field that drives them itself propagates at close to the speed of light , enabling electrical signals to pass rapidly along wires. Current causes several observable effects, which historically were the means of recognising its presence. That water could be decomposed by the current from a voltaic pile was discovered by Nicholson and Carlisle in 1800,

2567-553: A more reliable source of electrical energy than the electrostatic machines previously used. The recognition of electromagnetism , the unity of electric and magnetic phenomena, is due to Hans Christian Ørsted and André-Marie Ampère in 1819–1820. Michael Faraday invented the electric motor in 1821, and Georg Ohm mathematically analysed the electrical circuit in 1827. Electricity and magnetism (and light) were definitively linked by James Clerk Maxwell , in particular in his " On Physical Lines of Force " in 1861 and 1862. While

2718-417: A number of the transformers along with a Siemens generator and set his engineers to experimenting with them in the hopes of improving them for use in a commercial power system. One of Westinghouse's engineers, William Stanley , recognised the problem with connecting transformers in series as opposed to parallel and also realised that making the iron core of a transformer a fully enclosed loop would improve

2869-425: A positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part. Current defined in this manner is called conventional current . The motion of negatively charged electrons around an electric circuit , one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of

3020-891: A practical generator, but it showed the possibility of generating electric power using magnetism, a possibility that would be taken up by those that followed on from his work. An electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task. The components in an electric circuit can take many forms, which can include elements such as resistors , capacitors , switches , transformers and electronics . Electronic circuits contain active components , usually semiconductors , and typically exhibit non-linear behaviour, requiring complex analysis. The simplest electric components are those that are termed passive and linear : while they may temporarily store energy, they contain no sources of it, and exhibit linear responses to stimuli. The resistor

3171-617: A practical two-phase induction motor which Westinghouse licensed for his AC system. By 1890 the power industry had flourished and power companies had built thousands of power systems (both direct and alternating current) in the United States and Europe – these networks were effectively dedicated to providing electric lighting. During this time a fierce rivalry in the US known as the " war of the currents " emerged between Edison and Westinghouse over which form of transmission (direct or alternating current)

SECTION 20

#1733106666553

3322-406: A process now known as electrolysis . Their work was greatly expanded upon by Michael Faraday in 1833. Current through a resistance causes localised heating, an effect James Prescott Joule studied mathematically in 1840. One of the most important discoveries relating to current was made accidentally by Hans Christian Ørsted in 1820, when, while preparing a lecture, he witnessed the current in

3473-471: A rapidly changing one. Electric power is the rate at which electric energy is transferred by an electric circuit . The SI unit of power is the watt , one joule per second . Electric power, like mechanical power , is the rate of doing work , measured in watts , and represented by the letter P . The term wattage is used colloquially to mean "electric power in watts." The electric power in watts produced by an electric current I consisting of

3624-485: A resistance is directly proportional to the potential difference across it. The resistance of most materials is relatively constant over a range of temperatures and currents; materials under these conditions are known as 'ohmic'. The ohm , the unit of resistance, was named in honour of Georg Ohm , and is symbolised by the Greek letter Ω. 1 Ω is the resistance that will produce a potential difference of one volt in response to

3775-638: A result only the convent was sacked. On 13 May 1534, at the Battle of Lauffen, the 11,000 troops of Austria were outnumbered by those of the Rulers of Hesse , whose forces consisted of some 25,000 men. As a result of the victory over the Austrians, Ulrich, Duke of Württemberg regained his territory and led his subjects towards the Reformation. Lauffen was occupied for over a year in approximately 1547 by Imperial troops during

3926-505: A result, hegemony over the town changed frequently, transferring to (among others) the Dukes of Teck . In 1327, Lauffen was mortgaged to Württemberg. In 1346, Sir Albrecht (Ritter Albrecht Hofwarth) acquired town and castle from the Margraves of Baden for 3,000 heller . However, in 1361, he resold his acquisition to Graf Eberhard von Württemberg and his brother for double the purchase price. Due to

4077-595: A running total of the electric energy delivered to a customer. Unlike fossil fuels , electricity is a low entropy form of energy and can be converted into motion or many other forms of energy with high efficiency. Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes , transistors , diodes , sensors and integrated circuits , and associated passive interconnection technologies. The nonlinear behaviour of active components and their ability to control electron flows makes digital switching possible, and electronics

4228-431: A scientific curiosity into an essential tool for modern life. In 1887, Heinrich Hertz discovered that electrodes illuminated with ultraviolet light create electric sparks more easily. In 1905, Albert Einstein published a paper that explained experimental data from the photoelectric effect as being the result of light energy being carried in discrete quantized packets, energising electrons. This discovery led to

4379-568: A series of experiments to the Royal Society on the shocks delivered by the electric eel ; that same year the surgeon and anatomist John Hunter described the structure of the fish's electric organs . In 1791, Luigi Galvani published his discovery of bioelectromagnetics , demonstrating that electricity was the medium by which neurons passed signals to the muscles. Alessandro Volta 's battery, or voltaic pile , of 1800, made from alternating layers of zinc and copper, provided scientists with

4530-510: A series of observations on static electricity around 600 BCE, from which he believed that friction rendered amber magnetic , in contrast to minerals such as magnetite , which needed no rubbing. Thales was incorrect in believing the attraction was due to a magnetic effect, but later science would prove a link between magnetism and electricity. According to a controversial theory, the Parthians may have had knowledge of electroplating , based on

4681-566: A set of equations that could unambiguously describe the interrelationship between electric field, magnetic field, electric charge, and electric current. He could moreover prove that in a vacuum such a wave would travel at the speed of light , and thus light itself was a form of electromagnetic radiation. Maxwell's equations , which unify light, fields, and charge are one of the great milestones of theoretical physics. Lauffen am Neckar Lauffen am Neckar ( German pronunciation: [ˌlaʊfn̩ ʔam ˈnɛkaʁ] ) or simply Lauffen

Power engineering - Misplaced Pages Continue

4832-477: A solid crystal (such as a germanium crystal) to detect a radio signal by the contact junction effect. In a solid-state component, the current is confined to solid elements and compounds engineered specifically to switch and amplify it. Current flow can be understood in two forms: as negatively charged electrons , and as positively charged electron deficiencies called holes . These charges and holes are understood in terms of quantum physics. The building material

4983-528: A spear of the same headed Azure . The town's colours are green and white. Lauffen originally bore the coat of arms of the founders of the town, the Grafen von Lauffen (the Earls of Lauffen). This was a clawless eagle (cp. the present arms of the district of Heilbronn). From 1220 to 1346, the town was a possession of Baden , and in 1311 the arms of Baden first appeared in a Lauffen seal. The present coat of arms, one of

5134-418: A variety of reasons. For example, in remote locations it may be cheaper for a mine to generate its own power rather than pay for connection to the grid and in most mobile applications connection to the grid is simply not practical. Electricity generation covers the selection, design and construction of facilities that convert energy from primary forms to electric power. Electric power transmission requires

5285-511: A wire disturbing the needle of a magnetic compass. He had discovered electromagnetism , a fundamental interaction between electricity and magnetics. The level of electromagnetic emissions generated by electric arcing is high enough to produce electromagnetic interference , which can be detrimental to the workings of adjacent equipment. In engineering or household applications, current is often described as being either direct current (DC) or alternating current (AC). These terms refer to how

5436-448: A wire suspended from a pivot above the magnet and dipped into the mercury. The magnet exerted a tangential force on the wire, making it circle around the magnet for as long as the current was maintained. Experimentation by Faraday in 1831 revealed that a wire moving perpendicular to a magnetic field developed a potential difference between its ends. Further analysis of this process, known as electromagnetic induction , enabled him to state

5587-402: A wire. The informal term static electricity refers to the net presence (or 'imbalance') of charge on a body, usually caused when dissimilar materials are rubbed together, transferring charge from one to the other. Charge can be measured by a number of means, an early instrument being the gold-leaf electroscope , which although still in use for classroom demonstrations, has been superseded by

5738-584: Is a scalar quantity . That is, it has only magnitude and not direction. It may be viewed as analogous to height : just as a released object will fall through a difference in heights caused by a gravitational field, so a charge will 'fall' across the voltage caused by an electric field. As relief maps show contour lines marking points of equal height, a set of lines marking points of equal potential (known as equipotentials ) may be drawn around an electrostatically charged object. The equipotentials cross all lines of force at right angles. They must also lie parallel to

5889-411: Is a vector field . The study of electric fields created by stationary charges is called electrostatics . The field may be visualised by a set of imaginary lines whose direction at any point is the same as that of the field. This concept was introduced by Faraday, whose term ' lines of force ' still sometimes sees use. The field lines are the paths that a point positive charge would seek to make as it

6040-592: Is a far superior dielectric to air and, in recent times, its use has been extended to produce far more compact switching equipment (known as switchgear ) and transformers . Many important developments also came from extending innovations in the ICT field to the power engineering field. For example, the development of computers meant load flow studies could be run more efficiently allowing for much better planning of power systems. Advances in information technology and telecommunication also allowed for much better remote control of

6191-457: Is a town in the district of Heilbronn , Baden-Württemberg, Germany. It is on the river Neckar , 9 kilometres (6 miles) southwest of Heilbronn . The town is famous as the birthplace of the poet Friedrich Hölderlin and for its quality wines – in particular the "Lauffener Katzenbeißer Schwarzriesling". Lauffen is located in the southern part of the district of Heilbronn, 9 km (6 mi) south of Heilbronn and 50 km (31 mi) north of

Power engineering - Misplaced Pages Continue

6342-428: Is also a New Apostolic Church and congregation in the town. Following the municipal election of 7 June 2009, the district council of Lauffen has 22 seats. The election result is as follows: The mayor is also a member of the district council and its chairman. Blazon : Argent a messenger vested Vert in shoes Gules , holding in his dexter hand an envelope of the field sealed of the third and in his sinister hand

6493-413: Is an electric current and produces a magnetic field . In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the work done to move an electric charge from one point to another within an electric field, typically measured in volts . Electricity plays a central role in many modern technologies, serving in electric power where electric current

6644-452: Is an important difference. Gravity always acts in attraction, drawing two masses together, while the electric field can result in either attraction or repulsion. Since large bodies such as planets generally carry no net charge, the electric field at a distance is usually zero. Thus gravity is the dominant force at distance in the universe, despite being much weaker. An electric field generally varies in space, and its strength at any one point

6795-475: Is by the Neckar. Neighbouring towns and villages of Lauffen are (clockwise from the west): Brackenheim , Nordheim , Heilbronn , Talheim , Isfeld, Neckarwestheim and Kirchheim am Neckar (District of Ludwigsburg ). The exclave Stadtwald Etzlenswenden is surrounded (from the west) by Abstatt , Untergruppenbach , Löwenstein and Beilstein . All neighbouring villages as far as Heilbronn and Kircheim come under

6946-401: Is charged by the glass rod, and the other by an amber rod, the two balls are found to attract each other. These phenomena were investigated in the late eighteenth century by Charles-Augustin de Coulomb , who deduced that charge manifests itself in two opposing forms. This discovery led to the well-known axiom: like-charged objects repel and opposite-charged objects attract . The force acts on

7097-468: Is defined as negative, and that by protons is positive. Before these particles were discovered, Benjamin Franklin had defined a positive charge as being the charge acquired by a glass rod when it is rubbed with a silk cloth. A proton by definition carries a charge of exactly 1.602 176 634 × 10  coulombs . This value is also defined as the elementary charge . No object can have a charge smaller than

7248-483: Is defined as the force (per unit charge) that would be felt by a stationary, negligible charge if placed at that point. The conceptual charge, termed a ' test charge ', must be vanishingly small to prevent its own electric field disturbing the main field and must also be stationary to prevent the effect of magnetic fields . As the electric field is defined in terms of force , and force is a vector , having both magnitude and direction , it follows that an electric field

7399-554: Is described in the section 'Economy and infrastructure' below. In 1914, two districts (Lauffen-Stadt and Lauffen-Dorf) were merged to create the new town of Lauffen am Neckar. The new town council marked the occasion by planting a lime tree in the terraced garden in front of the Pfalzgrafenburg castle. This tree stands opposite another lime at the Regiswindis Church on the other bank, the two trees thus symbolising unity. Of

7550-531: Is integral to applications spanning transport , heating , lighting , communications , and computation , making it the foundation of modern industrial society. Long before any knowledge of electricity existed, people were aware of shocks from electric fish . Ancient Egyptian texts dating from 2750 BCE described them as the "protectors" of all other fish. Electric fish were again reported millennia later by ancient Greek , Roman and Arabic naturalists and physicians . Several ancient writers, such as Pliny

7701-483: Is located further east in the Löwenstein Mountains. It is presumed that this forested area was allocated to the town by its founders in around AD 1200, as there was no other forest within its boundaries from which timber and firewood could be obtained. It is here, in the exclave, that the highest point is situated 452 m (1,483 ft) above sea level; the lowest point 154 m (505 ft) above sea level

SECTION 50

#1733106666553

7852-406: Is mediated by the magnetic field each current produces and forms the basis for the international definition of the ampere . This relationship between magnetic fields and currents is extremely important, for it led to Michael Faraday's invention of the electric motor in 1821. Faraday's homopolar motor consisted of a permanent magnet sitting in a pool of mercury . A current was allowed through

8003-415: Is most often a crystalline semiconductor . Solid-state electronics came into its own with the emergence of transistor technology. The first working transistor, a germanium -based point-contact transistor , was invented by John Bardeen and Walter Houser Brattain at Bell Labs in 1947, followed by the bipolar junction transistor in 1948. By modern convention, the charge carried by electrons

8154-503: Is now the site of the Neckarwestheim Nuclear Power Plant (GKN). Between 1935 and 1938, work took place on the so-called ‘Neckar-Enz Line’ between Eberbach and Unterriexingen. This was a series of fortifications designed to resist a possible attack from the west. Eleven bunkers were constructed in the Lauffen sector, none of which had any impact on the end of the war. There are two locks at Lauffen, both upstream of

8305-423: Is part of the town's original moat which has been overbuilt with timber-framed houses. At one time it was the route for river traffic, which included even motorised craft. The various clubs and societies include cultural organisations such as a music school and choirs, sports bodies like a rowing club and a swimming club, and parent-teacher associations linked to local schools. In all there are over 70 such bodies:

8456-403: Is perhaps the simplest of passive circuit elements: as its name suggests, it resists the current through it, dissipating its energy as heat. The resistance is a consequence of the motion of charge through a conductor: in metals, for example, resistance is primarily due to collisions between electrons and ions. Ohm's law is a basic law of circuit theory , stating that the current passing through

8607-411: Is presumed that the area around Lauffen had already been settled in pre-Christian times, although the only evidence consists of a few bones. The settlement's high level of frequentation can be attributed to the shallow water between the present old Neckar bridge and the cliffs by the castle and Regiswindis Church. Here the river was fordable for most of the year and the spot used by both men and animals as

8758-531: Is subjected to transients , such as when first energised. The concept of the electric field was introduced by Michael Faraday . An electric field is created by a charged body in the space that surrounds it, and results in a force exerted on any other charges placed within the field. The electric field acts between two charges in a similar manner to the way that the gravitational field acts between two masses , and like it, extends towards infinity and shows an inverse square relationship with distance. However, there

8909-406: Is termed the inductance . The unit of inductance is the henry , named after Joseph Henry , a contemporary of Faraday. One henry is the inductance that will induce a potential difference of one volt if the current through it changes at a rate of one ampere per second. The inductor's behaviour is in some regards converse to that of the capacitor: it will freely allow an unchanging current, but opposes

9060-415: Is the farad , named after Michael Faraday , and given the symbol F : one farad is the capacitance that develops a potential difference of one volt when it stores a charge of one coulomb. A capacitor connected to a voltage supply initially causes a current as it accumulates charge; this current will however decay in time as the capacitor fills, eventually falling to zero. A capacitor will therefore not permit

9211-409: Is the site of today's Regiswindis Church. This hill settlement became known as Lauffen-Dorf (Lauffen village). In the middle of the river, between the two hills, is an island with a castle. This castle, originally the seat of the Earls of Lauffen, is now home to the town hall – the island itself is a nature reserve. Another settlement, Lauffen-Stadt (Lauffen town), later established itself on the hill on

SECTION 60

#1733106666553

9362-524: Is therefore 0 at all places inside the body. This is the operating principal of the Faraday cage , a conducting metal shell which isolates its interior from outside electrical effects. The principles of electrostatics are important when designing items of high-voltage equipment. There is a finite limit to the electric field strength that may be withstood by any medium. Beyond this point, electrical breakdown occurs and an electric arc causes flashover between

9513-409: Is used to energise equipment, and in electronics dealing with electrical circuits involving active components such as vacuum tubes , transistors , diodes and integrated circuits , and associated passive interconnection technologies. The study of electrical phenomena dates back to antiquity, with theoretical understanding progressing slowly until the 17th and 18th centuries. The development of

9664-409: Is usually measured in volts , and one volt is the potential for which one joule of work must be expended to bring a charge of one coulomb from infinity. This definition of potential, while formal, has little practical application, and a more useful concept is that of electric potential difference , and is the energy required to move a unit charge between two specified points. An electric field has

9815-536: Is widely used in information processing , telecommunications , and signal processing . Interconnection technologies such as circuit boards , electronics packaging technology, and other varied forms of communication infrastructure complete circuit functionality and transform the mixed components into a regular working system . Today, most electronic devices use semiconductor components to perform electron control. The underlying principles that explain how semiconductors work are studied in solid state physics , whereas

9966-700: The Neo-Latin word electricus ("of amber" or "like amber", from ἤλεκτρον, elektron , the Greek word for "amber") to refer to the property of attracting small objects after being rubbed. This association gave rise to the English words "electric" and "electricity", which made their first appearance in print in Thomas Browne 's Pseudodoxia Epidemica of 1646. Isaac Newton made early investigations into electricity, with an idea of his written down in his book Opticks arguably

10117-465: The Thury system ) although this suffered from serious reliability issues. In 1957 Siemens demonstrated the first solid-state rectifier (solid-state rectifiers are now the standard for HVDC systems) however it was not until the early 1970s that this technology was used in commercial power systems. In 1959 Westinghouse demonstrated the first circuit breaker that used SF 6 as the interrupting medium. SF 6

10268-525: The Tübingen - Würzburg (via Stuttgart ) route. At the time, this accident was the worst since the Second World War, killing 45 and seriously injuring a further 27. The cause of the accident was attributed to human error on the part of the level-crossing keeper; the level-crossing has since been replaced by an underpass. A commemorative plaque was erected in memory of those who lost their lives. Following

10419-423: The electromagnetic force , one of the four fundamental forces of nature. Experiment has shown charge to be a conserved quantity , that is, the net charge within an electrically isolated system will always remain constant regardless of any changes taking place within that system. Within the system, charge may be transferred between bodies, either by direct contact, or by passing along a conducting material, such as

10570-511: The quantum revolution. Einstein was awarded the Nobel Prize in Physics in 1921 for "his discovery of the law of the photoelectric effect". The photoelectric effect is also employed in photocells such as can be found in solar panels . The first solid-state device was the " cat's-whisker detector " first used in the 1900s in radio receivers. A whisker-like wire is placed lightly in contact with

10721-452: The strong interaction , but unlike that force it operates over all distances. In comparison with the much weaker gravitational force , the electromagnetic force pushing two electrons apart is 10 times that of the gravitational attraction pulling them together. Charge originates from certain types of subatomic particles , the most familiar carriers of which are the electron and proton . Electric charge gives rise to and interacts with

10872-555: The voltage regulation of the secondary winding. Using this knowledge he built the world's first practical transformer based alternating current power system at Great Barrington, Massachusetts in 1886. In 1885 the Italian physicist and electrical engineer Galileo Ferraris demonstrated an induction motor and in 1887 and 1888 the Serbian-American engineer Nikola Tesla filed a range of patents related to power systems including one for

11023-538: The 1936 discovery of the Baghdad Battery , which resembles a galvanic cell , though it is uncertain whether the artifact was electrical in nature. Electricity would remain little more than an intellectual curiosity for millennia until 1600, when the English scientist William Gilbert wrote De Magnete , in which he made a careful study of electricity and magnetism, distinguishing the lodestone effect from static electricity produced by rubbing amber. He coined

11174-543: The Anglo-Dutch cavalry crossed the Neckar at Lauffen, and in 1707, 2000 French horsemen sacked the town for a second time. 1709, a cuirassier regiment from Kürnbach was quartered there. However, more than 100 years after the outbreak of the Thirty Years' War , Lauffen was starting to recover from the damage which had been inflicted. In 1721, the town hall was rebuilt and in 1724 the temporarily repaired bridge dating from 1693

11325-733: The Battle of Lauffen in 1534, the town became the first in Württemberg to embrace the Reformation . A reference to the first Protestant vicar, Hieronymus Hailbrunner, occurs in 1546 but he was no doubt already in office before this date. Since then, a majority of the town's worshippers has been of the Protestant faith. A Roman Catholic congregation did not exist until 1946. The Protestant congregation numbers some 6,000; there are approximately 3,000 Roman Catholics, some of whom are in Neckarwestheim. There

11476-496: The Bavarians and extensive defences were constructed. After the armistice of 1647 between France and Bavaria, the town's defences were razed to the ground. The Bavarians withdrew, to be replaced over the winter by a company of Weimar cavalry. With the failure of the armistice, a French garrison arrived and set about constructing more defences, which nevertheless became redundant with the conclusion of peace in 1648. For many years after

11627-645: The Elder and Scribonius Largus , attested to the numbing effect of electric shocks delivered by electric catfish and electric rays , and knew that such shocks could travel along conducting objects. Patients with ailments such as gout or headache were directed to touch electric fish in the hope that the powerful jolt might cure them. Ancient cultures around the Mediterranean knew that certain objects, such as rods of amber , could be rubbed with cat's fur to attract light objects like feathers. Thales of Miletus made

11778-674: The Electrical Engineering Exhibition in Frankfurt. In 1895, after a protracted decision-making process, the Adams No. 1 generating station at Niagara Falls began transmitting three-phase alternating current power to Buffalo at 11 kV. Following completion of the Niagara Falls project, new power systems increasingly chose alternating current as opposed to direct current for electrical transmission. The generation of electricity

11929-463: The French army arrived, confiscating all the horses and destroying the bridge. During the following decade, the area witnessed more hostilities and was again occupied. Yet more looting occurred, along with the destruction of agricultural land. The population, which had increased between the two wars, was later decimated to 210 persons in 1697. The 18th century was also dominated by matters military. In 1704

12080-595: The Landkreis (district) Heilbronn. Lauffen has combined with Neckarwestheim and Nordheim to form a joint association of administrations. The localities of Lauffen-Stadt (town) and Lauffen-Dorf (village) were combined on 1 April 1914 to create today's Lauffen am Neckar. The outlying farmsteads of the Landturm, an old customs house on the former Württemberg boundary, are included as part of the town. The defunct hamlets of Osterhofen and Talhofen originally lay within its bounds. It

12231-541: The Neckar on the way to Strasbourg , to be followed by the Lüneburg-Zellsche army. Upon the withdrawal of these forces, the Brandenburgers set up their headquarters at Isfeld. In May 1675, the imperial army, arriving from The Netherlands, crossed the river near Lauffen. In 1676, the town served as winter quarters for an imperial regiment of cuirassiers and, in 1679, for a company of cavalry from Lorraine. In 1688,

12382-446: The Neckar slopes and the first castle can be traced back to Ernst. According to legend, the Graf's infant daughter, Regiswindis, was murdered by her wet nurse and the body thrown into the Neckar. After this incident, the margrave Ernst returned to his home in the Upper Palatinate and the village was transferred back to the emperor with effect from 861, before the expiration of the lease and

12533-633: The arrival of the Gaugrafen von Lauffen (Frankish earls) who were allied to the Bishopric of Worms and noble descendants of the Poppon tribe of Lauffen. They pressed ahead with the fortification of the settlement and of the castle. In around 1150, they had the rocks on the eastern riverbank cut back, thus creating the basis for a moated castle – the present-day "Pfalzgrafenburg". The three brothers – Heinrich II, Boppo V and Konrad II – all died without male issue. With

12684-406: The banks of the Neckar. Agriculture continued to increase in importance. From 2000 inhabitants in 1800, the population increased to approximately 4000 in 1850. The section of railway between Stuttgart and Heilbronn was completed in 1847, giving rise to the construction of buildings around the railway station. Following a fire on 14 October 1861, a volunteer fire brigade was formed on 19 November of

12835-408: The beginning of the field theory of the electric force. Further work was conducted in the 17th and early 18th centuries by Otto von Guericke , Robert Boyle , Stephen Gray and C. F. du Fay . Later in the 18th century, Benjamin Franklin conducted extensive research in electricity, selling his possessions to fund his work. In June 1752 he is reputed to have attached a metal key to the bottom of

12986-549: The bombers had been in northern Württemberg, Hesse or the Ruhr. As was so often the case, a return to base with the bomb load had not been included in the fuel calculations. The bombing of Lauffen can thus be regarded as the sacrifice of a pawn – a sacrifice in favour of a city. On 20 June 1959, there was a serious accident at Lauffen when a public service bus operated by the Deutsche Bundesbahn crashed into an express train on

13137-524: The bombs, which were dropped at random and in some cases unprimed. Most fell in fields or the river although some dropped on the Sonnenstrasse, the Brückenstrasse, the old cemetery and in the vicinity of the cement works and St Martin's Church. There were 59 fatalities including a number of forced labourers. The then mayor was criticised for not having sounded the air raid warning. Secondary targets for

13288-419: The building it serves to protect. The concept of electric potential is closely linked to that of the electric field. A small charge placed within an electric field experiences a force, and to have brought that charge to that point against the force requires work . The electric potential at any point is defined as the energy required to bring a unit test charge from an infinite distance slowly to that point. It

13439-579: The canal was given high priority – several houses and even the first commercial three-phase power station were demolished. The original generator is now on display at the Deutsches Museum in Munich. Nearby, the Oskar von Miller Strasse (the westerly access road to the cement works) is a reminder of the power station's previous location. Electricity has since been generated at the dam further upstream. Parallel with

13590-471: The capital of Baden-Württemberg , Stuttgart , on the Neckar . The small river Zaber flows into the Neckar at this point. The neck of the previous great bow in the course of the north-flowing Neckar was broken through by erosion somewhere between 400 BC and 100 BC and for several centuries the watercourse survived as a ring of lakes. The old circular riverbed is now dry, apart from one small artificial lake. Along

13741-593: The castle. The first was constructed between 1938 and 1945 – the second between 1950 and 1951. Following boundary change legislation in 1938, the administrative area known as the Oberamt Besigheim was dissolved and Lauffen became part of the Landkreis Heilbronn (district of Heilbronn). During the Second World War the town suffered 37 air raids, this number being partly influenced by its proximity to

13892-426: The charged particles themselves, hence charge has a tendency to spread itself as evenly as possible over a conducting surface. The magnitude of the electromagnetic force, whether attractive or repulsive, is given by Coulomb's law , which relates the force to the product of the charges and has an inverse-square relation to the distance between them. The electromagnetic force is very strong, second only in strength to

14043-450: The charged parts. Air, for example, tends to arc across small gaps at electric field strengths which exceed 30 kV per centimetre. Over larger gaps, its breakdown strength is weaker, perhaps 1 kV per centimetre. The most visible natural occurrence of this is lightning , caused when charge becomes separated in the clouds by rising columns of air, and raises the electric field in the air to greater than it can withstand. The voltage of

14194-474: The choir three years previously. The church dates from 1227, when it was dedicated to Saint Regiswindis, but previous structures (St Martin's Church) date back to 741. Fragments of a Mount of Olives painting C 1507 by Hans Seyfer survive on the exterior of the choir. Regiswindis Chapel: Originally a graveyard chapel dedicated to Saint Ann, its crypt served as a charnel house. In 1901, the piles of bones were collected and buried. The stone sarcophagus containing

14345-425: The close of the exhibition, transmission of current from the Lauffen three-phase alternator was maintained to Heilbronn, which thus became the first town in the world to receive a regular supply of electricity from a remote location. To this day, the name of the local electricity utility, ZEAG (Zementwerk Lauffen – Elektrizitätswerk Heilbronn AG), is a reminder of this achievement. The Lauffen winemaking cooperative

14496-418: The construction of the canal came the laying of a narrow gauge railway for the transportation of stone along the right bank of the river between the Lauffen cement works and the quarry at Neckarwestheim . The railway ceased operation in 1984, with the rails later removed to create a new footpath and cycle way. The engine is preserved on a playground near the old bridge beside the former railway track. The quarry

14647-544: The cooperative, other growers cultivate and market their own wines independently. The vineyards at Lauffen are part of the greater Kirchenweinberg area of the Württemberg lowland winegrowing region. An annual event is the selection of Württemberg's ‘Weinkönigin’ (Wine Queen), whose role it is to represent the winegrowing industry at events not only in Württemberg , but also throughout Germany and elsewhere in Europe. A prerequisite for

14798-411: The current varies in time. Direct current, as produced by example from a battery and required by most electronic devices, is a unidirectional flow from the positive part of a circuit to the negative. If, as is most common, this flow is carried by electrons, they will be travelling in the opposite direction. Alternating current is any current that reverses direction repeatedly; almost always this takes

14949-409: The death of the Graf. In 889, 923 and 993, various German emperors transferred their rule over the village to the Bishopric of Würzburg . In 1003, Henry II, Holy Roman Emperor called for the establishment of a convent in the village, which had meanwhile been fortified. A Benedictine convent was accordingly set up under the auspices of Bishop Heinrich von Würzburg. The end of the 11th century saw

15100-596: The death of the last scion in 1218 or 1219, the house of Lauffen died out, although its coat of arms survives to this day as the arms of the District of Heilbronn . In the 13th century, the town once again reverted to the German Emperor ( Holy Roman Emperor ). In 1227, the Holy Roman Emperor Frederick II mortgaged Lauffen, Sinsheim and Eppingen to Herman V of Baden. In the mortgage deed, Lauffen

15251-405: The decoy target known as ‘Brasilien’, which was laid out to look like the main railway station at Stuttgart . On 13 April 1944, an allied bomber formation was returning to base having failed to bomb its primary and secondary targets ( Nuremberg and Stuttgart ) when it was attacked by a German fighter and forced to jettison its load over Lauffen. The town escaped serious damage and casualties from

15402-516: The design and construction of electronic circuits to solve practical problems are part of electronics engineering . Faraday's and Ampère's work showed that a time-varying magnetic field created an electric field, and a time-varying electric field created a magnetic field. Thus, when either field is changing in time, a field of the other is always induced. These variations are an electromagnetic wave . Electromagnetic waves were analysed theoretically by James Clerk Maxwell in 1864. Maxwell developed

15553-488: The development of electrical engineering education. On an international level, the International Electrotechnical Commission (IEC), which was founded in 1906, prepares standards for power engineering, with 20,000 electrotechnical experts from 172 countries developing global specifications based on consensus. Electricity Electricity is the set of physical phenomena associated with

15704-478: The early 19th century had seen rapid progress in electrical science, the late 19th century would see the greatest progress in electrical engineering . Through such people as Alexander Graham Bell , Ottó Bláthy , Thomas Edison , Galileo Ferraris , Oliver Heaviside , Ányos Jedlik , William Thomson, 1st Baron Kelvin , Charles Algernon Parsons , Werner von Siemens , Joseph Swan , Reginald Fessenden , Nikola Tesla and George Westinghouse , electricity turned from

15855-456: The eastern bank. The two districts, Lauffen-Dorf and Lauffen-Stadt, are joined by a bridge. A smaller bridge from Lauffen-Stadt leads to the island and the town hall. Yet another district, the so-called Lauffen-Dörfle (Lauffen little village), grew up around a convent and is situated on the western bank to the north of Lauffen-Dorf and the Zaber. An exclave of Lauffen, the town's forest of Etzlenswenden,

16006-427: The effect was reciprocal: a current exerts a force on a magnet, and a magnetic field exerts a force on a current. The phenomenon was further investigated by Ampère , who discovered that two parallel current-carrying wires exerted a force upon each other: two wires conducting currents in the same direction are attracted to each other, while wires containing currents in opposite directions are forced apart. The interaction

16157-448: The electronic electrometer . The movement of electric charge is known as an electric current , the intensity of which is usually measured in amperes . Current can consist of any moving charged particles; most commonly these are electrons, but any charge in motion constitutes a current. Electric current can flow through some things, electrical conductors , but will not flow through an electrical insulator . By historical convention,

16308-416: The electrons. However, depending on the conditions, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation. The process by which electric current passes through a material is termed electrical conduction , and its nature varies with that of the charged particles and

16459-428: The elementary charge, and any amount of charge an object may carry is a multiple of the elementary charge. An electron has an equal negative charge, i.e. −1.602 176 634 × 10  coulombs . Charge is possessed not just by matter , but also by antimatter , each antiparticle bearing an equal and opposite charge to its corresponding particle. The presence of charge gives rise to an electrostatic force: charges exert

16610-460: The end of the war, and at frequent intervals, Lauffen would be taken over and occupied by troops. At the end of the Thirty Years' War , the population was 155. The upper castle had been destroyed, the lower one severely damaged. The town's church was also badly damaged. In all, 270 houses were damaged and 452 acres (1.8 km ) of vineyards, 1,239 acres (5.0 km ) of fields and 50 acres (0.20 km ) of meadows had been laid to waste. Since

16761-518: The engineer will require as much in the way of administrative and organizational skills as electrical engineering knowledge. In both the UK and the US, professional societies had long existed for civil and mechanical engineers. The Institution of Electrical Engineers (IEE) was founded in the UK in 1871, and the AIEE in the United States in 1884. These societies contributed to the exchange of electrical knowledge and

16912-435: The engineering of high voltage transmission lines and substation facilities to interface to generation and distribution systems. High voltage direct current systems are one of the elements of an electric power grid. Electric power distribution engineering covers those elements of a power system from a substation to the end customer. Power system protection is the study of the ways an electrical power system can fail, and

17063-511: The entire French general staff. The so-called "Weimar occupation" lasted until May 1643, when victory was achieved after three days of fighting by the Bavarian army under the command of Graf Fugger . In 1645, the town was again plundered by French and Hessian troops. Subsequently, the Bavarians moved back, but provisions were barely enough to feed them. Virtually all that remained were cabbages, beets and new wine. A year later, Swedish troops joined

17214-499: The entire winter crop, thus creating a famine which claimed 800 lives. In 1636, Lauffen was sacked by a Colonel Liddaw and his regiment of cuirassiers. In the autumn of 1637, it was overrun by two different regiments – a state of affairs which caused a shortage of food during the winter and resulted in the deaths of 200 people. In 1638, it had to endure the presence of a company of Parischen troops; then, in May and again in September, it

17365-578: The following year, the Palatinate Graf Friedrich gave an undertaking to stop attacks against various localities in Württemberg. Then, in 1469, a treaty between the Palatinate and Württemberg resolved the customs disputes over the transportation of timber along the River Murr . In 1474 the first bridge at Lauffen was built over the Neckar thus bringing the entire customs duties for river traffic to

17516-495: The form of a sine wave . Alternating current thus pulses back and forth within a conductor without the charge moving any net distance over time. The time-averaged value of an alternating current is zero, but it delivers energy in first one direction, and then the reverse. Alternating current is affected by electrical properties that are not observed under steady state direct current, such as inductance and capacitance . These properties however can become important when circuitry

17667-473: The higher voltages necessary to minimise power loss during transmission, the possible distance between the generators and load was limited to around half-a-mile (800 m). That same year in London Lucien Gaulard and John Dixon Gibbs demonstrated the first transformer suitable for use in a real power system. The practical value of Gaulard and Gibbs' transformer was demonstrated in 1884 at Turin where

17818-400: The material through which they are travelling. Examples of electric currents include metallic conduction, where electrons flow through a conductor such as metal, and electrolysis , where ions (charged atoms ) flow through liquids, or through plasmas such as electrical sparks. While the particles themselves can move quite slowly, sometimes with an average drift velocity only fractions of

17969-447: The methods to detect and mitigate for such failures. In most projects, a power engineer must coordinate with many other disciplines such as civil and mechanical engineers, environmental experts, and legal and financial personnel. Major power system projects such as a large generating station may require scores of design professionals in addition to the power system engineers. At most levels of professional power system engineering practice,

18120-489: The mid-1930s, work was started on the construction of a by-pass canal for the Neckar. This new canal had the effect of making the rocks of the Pfalzgrafenburg into an island once more. For a time, the cliff was linked to the town via a millrace which had been artificially created, and the Neckar sped in front of the cliffs and the bridge over rocks which had been placed there to produce rapids. (Pictures dating from 1640 and 1800 provide an interesting comparison.) The building of

18271-461: The old riverbed, a round hill was formed – its slopes now partially covered by the Kaywald forest and with other areas given over to the cultivation of vines. There is a hill on the western bank of the Neckar at the centre point of the ancient river bow. This hill became separated from another on the present eastern bank when the river broke through. Lauffen grew up on the western bank, on the ridge which

18422-449: The political situation in the second half of the 17th century was far from stable, Eberhard III strengthened the fortifications around Lauffen with drawbridges and parapets as a defence against potential attacks by the French. Just a few years after the devastating Thirty Years' War, Lauffen was the scene of invasions for a second time. In 1674, the army of the Elector of Brandenburg crossed

18573-484: The power system's switchgear and generators. Power Engineering deals with the generation , transmission , distribution and utilization of electricity as well as the design of a range of related devices. These include transformers , electric generators , electric motors and power electronics . Power engineers may also work on systems that do not connect to the grid. These systems are called off-grid power systems and may be used in preference to on-grid systems for

18724-481: The presence and motion of matter possessing an electric charge . Electricity is related to magnetism , both being part of the phenomenon of electromagnetism , as described by Maxwell's equations . Common phenomena are related to electricity, including lightning , static electricity , electric heating , electric discharges and many others. The presence of either a positive or negative electric charge produces an electric field . The motion of electric charges

18875-428: The principle, now known as Faraday's law of induction , that the potential difference induced in a closed circuit is proportional to the rate of change of magnetic flux through the loop. Exploitation of this discovery enabled him to invent the first electrical generator in 1831, in which he converted the mechanical energy of a rotating copper disc to electrical energy. Faraday's disc was inefficient and of no use as

19026-537: The proximity of the Free Imperial City of Heilbronn, the rulers of Württemberg demanded a commitment of loyalty from the inhabitants of Lauffen. The 15th century at Lauffen was characterized by conflicts over complex fishing and tithe rights which affected many of the inhabitants. The lake of Lauffen was created by Ulrich V, Count of Württemberg in 1454. In 1460, his troops were called upon to defend fishing and customs rights against Palatinate troops. However,

19177-458: The remains of Regiswindis were transferred to the chapel in 1882, at which point the building acquired its present name. *There are many historic buildings in the town centre, including dwellings in the baroque style dating from the 18th century, and those associated with the Kirchberg, which include an old bake house. The curious Grabengasse (moat lane) winds its way by the Kirchberg. This lane

19328-465: The same year. In 1889, the second shaft of the railway tunnel (584 m) was completed between Kircheim am Neckar and Lauffen, thus removing a major bottleneck on the Franconia Railway from Heilbronn to Stuttgart. The year 1891 saw the world's first long-distance transmission of alternating three-phase electric current. This important technical achievement – a link between Lauffen and Frankfurt Main –

19479-522: The site for a town hall. During the 19th century, emphasis was placed on agriculture. The lake of Lauffen was drained in 1820, thus producing 200 acres (0.8 km ) of additional land. With the lake gone, the inhabitants lost a rich source of food but, on the other hand, the water had also been the cause of fevers. Wine growing was improved by abandoning unprofitable varieties. The main variety became Pinot blanc . The town planted more than 2,000 fruit trees within its boundaries and countless willows along

19630-468: The soldiers who served in the First World War, 189 failed to return. A war memorial was erected in their honour in front of the town hall in 1922. This was removed in 1949 to make way for a widening of the canal, and to enable the plaque bearing the names of the fallen to be set into the wall of the old cemetery alongside another dedicated to the even greater number of victims of the Second World War. In

19781-555: The southeast of the present town centre. Archaeological excavations show that the Alemannians came to the area in around 260 AD upon the departure of the Romans. With the arrival of the Franks in 500 AD, a royal estate was founded together with a church dedicated to St Martin. The ownership of the estate alternated frequently between princes and church. A document from 823 refers to this “church in

19932-454: The special property that it is conservative , which means that the path taken by the test charge is irrelevant: all paths between two specified points expend the same energy, and thus a unique value for potential difference may be stated. The volt is so strongly identified as the unit of choice for measurement and description of electric potential difference that the term voltage sees greater everyday usage. For practical purposes, defining

20083-481: The theory of electromagnetism in the 19th century marked significant progress, leading to electricity's industrial and residential application by electrical engineers by the century's end. This rapid expansion in electrical technology at the time was the driving force behind the Second Industrial Revolution , with electricity's versatility driving transformations in both industry and society. Electricity

20234-471: The town. The bridge was destroyed by the flood of 1529 and rebuilt in 1532. A town hall was built and a weekly market established in 1480. Two years later, the bubonic plague caused the death of 1,300 inhabitants. During the German Peasants' War , an 8,000-strong army of peasants set up camp between Lauffen and Gemmrigheim in 1525. Bowing to superior force, the town council sided with the peasants – as

20385-455: The transformer was used to light up forty kilometres (25 miles) of railway from a single alternating current generator. Despite the success of the system, the pair made some fundamental mistakes. Perhaps the most serious was connecting the primaries of the transformers in series so that switching one lamp on or off would affect other lamps further down the line. Following the demonstration George Westinghouse , an American entrepreneur, imported

20536-462: The tribal district of Neckar which is dedicated to Saint Martin in the Villa Hlauppa.” The name "Hlauppa" (which has become "Lauffen") is characteristic of places with rapids or waterfalls. Other examples of this derivation are Laufen and Laufenburg . The rapids which are occasionally visible at Lauffen were created by erosion when the Neckar shortened its course after breaking through the neck of

20687-418: The two forces of nature then known. The force on the compass needle did not direct it to or away from the current-carrying wire, but acted at right angles to it. Ørsted's words were that "the electric conflict acts in a revolving manner." The force also depended on the direction of the current, for if the flow was reversed, then the force did too. Ørsted did not fully understand his discovery, but he observed

20838-424: The type which alludes to its owner, was first verified in a seal for the year 1464. Drawings of the arms in the natural colours survive from the year 1575, although the background of the shield sometimes appears tinged in gold rather than silver. Lauffen am Neckar is twinned with:- *Regiswindis Church: The rebuilding of the church in its present form was well underway by 1567 after a fire had destroyed all but

20989-417: The vector direction of the field is the line of greatest slope of potential, and where the equipotentials lie closest together. Ørsted's discovery in 1821 that a magnetic field existed around all sides of a wire carrying an electric current indicated that there was a direct relationship between electricity and magnetism. Moreover, the interaction seemed different from gravitational and electrostatic forces,

21140-472: The war of the Schmalkaldic League , then reverted to Württemberg. 1564 saw the return of the bubonic plague, which claimed some 800 victims. The plague returned in 1606, 1607 and 1626 although there were fewer fatalities. During the Thirty Years' War , Lauffen was the scene of several battles and troop movements. The bridge and the nearby ford proved to be of major strategic significance. In April 1622,

21291-536: Was abolished and Lauffen became an "Oberamt" (administrative area). Thirty years later, 160 inhabitants died of typhus . The Oberamt Lauffen was wound up in 1808, and the town came under the jurisdiction of the Oberamt Besigheim. Two years later, the bridge over the Neckar was again renovated, the wooden elements being replaced by masonry. In 1817, the council bought the Neckar Island with the intention of using

21442-781: Was another key figure involved, having been involved in the construction of a power station in Moscow in 1910. He had also known Lenin since 1897 when they were both in the St. Petersburg chapter of the Union of Struggle for the Liberation of the Working Class . In 1936 the first commercial high-voltage direct current (HVDC) line using mercury-arc valves was built between Schenectady and Mechanicville, New York . HVDC had previously been achieved by installing direct current generators in series (a system known as

21593-407: Was converted into a covered suspension bridge. From 1728, a night watch was established in response to a spate of murders and robberies. In 1744, Lauffen was besieged by the imperial Bavarian army under Feldmarschall von Seckendorff and 1754 witnessed repeated returns of the French. There followed subsequent occupations by troops from Wimpfen and Anhalt. In 1755, the previous protectorate structure

21744-472: Was first referred to as "civitas" (town with civic institutions). The upward designation to "town" is frequently dated as having taken place in the year 1234. The Margraves of Baden administered the town through a family of bailiffs. A church was built in 1227 to replace an existing chapel and dedicated to the now canonized Saint Regiswindis. The families of the ruling aristocracy were beset with problems over complex inheritance disputes and mortgage debts. As

21895-543: Was forced to move within the field; they are however an imaginary concept with no physical existence, and the field permeates all the intervening space between the lines. Field lines emanating from stationary charges have several key properties: first, that they originate at positive charges and terminate at negative charges; second, that they must enter any good conductor at right angles, and third, that they may never cross nor close in on themselves. A hollow conducting body carries all its charge on its outer surface. The field

22046-413: Was founded in 1935 and, with an annual yield of some six million litres and sales of approximately 22 million euros, is one of the largest high-quality cooperatives in the wine region of Württemberg . The cooperative has some 600 members, the area of vines covering approximately 570 hectares. Quality wines marketed under the name "Katzenbeißer" are especially well known. In addition to those forming part of

22197-433: Was installed in the cement works at Lauffen, with an overhead cable to carry the current under 15 kV to Frankfurt – a distance of 175 km (109 mi). The entrance to the exhibition was lit with 1000 light bulbs and the middle section surmounted by an arch bearing the inscription "Power Transmission Lauffen – Frankfurt 175 km". At the same time, an artificial waterfall some 6 m high was powered by electric current. At

22348-501: Was intermittent and in 1882 Thomas Edison and his company, The Edison Electric Light Company, developed the first steam-powered electric power station on Pearl Street in New York City. The Pearl Street Station consisted of several generators and initially powered around 3,000 lamps for 59 customers. The power station used direct current and operated at a single voltage. Since the direct current power could not be easily transformed to

22499-503: Was once more descended upon by imperial forces. In the autumn, two regiments of cavalry looted the harvest and, at the beginning of December, three cavalry regiments sacked the town. At Christmas 1638, the imperial general staff took over Lauffen. By the end of that year, the population had fallen to just 30. The misery continued during 1639 with frequent occupations by troops. The years 1640 to 1642 were comparatively quiet, but in 1643 French Weimar regiments were in occupation, along with

22650-475: Was regarded as particularly important following the Bolshevik seizure of power . Lenin stated "Communism is Soviet power plus the electrification of the whole country." He was subsequently featured on many Soviet posters, stamps etc. presenting this view. The GOELRO plan was initiated in 1920 as the first Bolshevik experiment in industrial planning and in which Lenin became personally involved. Gleb Krzhizhanovsky

22801-527: Was superior. In 1891, Westinghouse installed the first major power system that was designed to drive an electric motor and not just provide electric lighting. The installation powered a 100 horsepower (75 kW) synchronous motor at Telluride, Colorado with the motor being started by a Tesla induction motor. On the other side of the Atlantic, Oskar von Miller built a 20 kV 176 km three-phase transmission line from Lauffen am Neckar to Frankfurt am Main for

#552447