A pantograph is an apparatus mounted on the roof of an electric train, tram or electric bus to collect power through contact with an overhead line. It is a common type of current collector. A single or double wire is used, with the return current running through the track; the term stems from the resemblance of some styles to the mechanical pantographs used for copying handwriting and drawings. The pantograph, with a low-friction, replaceable graphite contact strip or'shoe' to minimise lateral stress on the contact wire, was invented in 1879 by Walter Reichel, chief engineer at Siemens & Halske in Germany. A flat slide-pantograph was invented in 1895 at the Baltimore and Ohio RailroadThe familiar diamond-shaped roller pantograph was invented by John Q. Brown of the Key System shops for their commuter trains which ran between San Francisco and the East Bay section of the San Francisco Bay Area in California, they appear in photographs of the first day of service, 26 October 1903. For many decades thereafter, the same diamond shape was used by electric-rail systems around the world and remains in use by some today.
The pantograph was an improvement on the simple trolley pole, which prevailed up to that time because the pantograph allows an electric-rail vehicle to travel at much higher speeds without losing contact with the overhead lines, e.g. due to dewirement of the trolley pole. Notwithstanding this, trolley pole current collection was used at up to 90 mph on the Electroliner vehicles of the Chicago North Shore and Milwaukee Railroad known as the North Shore Line; the most common type of pantograph today is the so-called half-pantograph, which evolved to provide a more compact and responsive single-arm design at high speeds as trains got faster. Louis Faiveley invented this type of pantograph in 1955; the half-pantograph can be seen in use on everything from fast trains to low-speed urban tram systems. The design operates with equal efficiency in either direction of motion, as demonstrated by the Swiss and Austrian railways whose newest high performance locomotives, the Re 460 and Taurus, operate with them set in the opposite direction.
The geometry and shape of the pantographs are specified by the EN 50367/IEC 60486 - Railway applications - Current collection systems - Technical criteria for the interaction between pantograph and overhead line. The electric transmission system for modern electric rail systems consists of an upper, weight-carrying wire from, suspended a contact wire; the pantograph is spring-loaded and pushes a contact shoe up against the underside of the contact wire to draw the current needed to run the train. The steel rails of the tracks act as the electrical return; as the train moves, the contact shoe slides along the wire and can set up standing waves in the wires which break the contact and degrade current collection. This means. Pantographs are the successor technology to trolley poles, which were used on early streetcar systems. Trolley poles are still used by trolleybuses, whose freedom of movement and need for a two-wire circuit makes pantographs impractical, some streetcar networks, such as the Toronto streetcar system, which have frequent turns sharp enough to require additional freedom of movement in their current collection to ensure unbroken contact.
However, many of these networks, including Toronto's, are undergoing upgrades to accommodate pantograph operation. Pantographs with overhead wires are now the dominant form of current collection for modern electric trains because, although more fragile than a third rail system, they allow the use of higher voltages. Pantographs are operated by compressed air from the vehicle's braking system, either to raise the unit and hold it against the conductor or, when springs are used to effect the extension, to lower it; as a precaution against loss of pressure in the second case, the arm is held in the down position by a catch. For high-voltage systems, the same air supply is used to "blow out" the electric arc when roof-mounted circuit breakers are used. Pantographs may have a double arm. Double-arm pantographs are heavier, requiring more power to raise and lower, but may be more fault-tolerant. On railways of the former USSR, the most used pantographs are those with a double arm, but since the late 1990s there have been some single-arm pantographs on Russian railways.
Some streetcars use double-arm pantographs, among them the Russian KTM-5, KTM-8, LVS-86 and many other Russian-made trams, as well as some Euro-PCC trams in Belgium. American streetcars use either trolley poles or single-arm pantographs. Most rapid transit systems are powered by a third rail, but some use pantographs ones that involve extensive above-ground running. Most hybrid metro-tram or'pre-metro' lines whose routes include tracks on city streets or in other publicly accessible areas, such as line 51 of the Amsterdam Metro, the MBTA Green Line, RTA Rapid Transit in Cleveland, Frankfurt am Main U-Bahn, San Francisco's Muni Metro, use overhead wire, as a standard third rail would obstruct street traffic and present too great a risk of electrocution. Among the various exceptions are several tram systems, such as the ones in Bordeaux, Angers and Dubai that use a proprietary underground system developed by Alstom, called APS, which only applies power to segments of track that are covered by the tram.
This system was designed to be used in the historic centre of Bordeaux because an overhead wire system would cause a visual intrusion. Similar systems that avoid overhead lines have been developed by Bombardier, AnsaldoBreda, CAF, and
On a steam locomotive, a driving wheel is a powered wheel, driven by the locomotive's pistons. On a conventional, non-articulated locomotive, the driving wheels are all coupled together with side rods. On diesel and electric locomotives, the driving wheels may be directly driven by the traction motors. Coupling rods are not used, it is quite common for each axle to have its own motor. Jackshaft drive and coupling rods were used in the past but their use is now confined to shunting locomotives. On an articulated locomotive or a duplex locomotive, driving wheels are grouped into sets which are linked together within the set. Driving wheels are larger than leading or trailing wheels. Since a conventional steam locomotive is directly driven, one of the few ways to'gear' a locomotive for a particular performance goal is to size the driving wheels appropriately. Freight locomotives had driving wheels between 40 and 60 inches in diameter; some long wheelbase locomotives were equipped with blind drivers.
These were driving wheels without the usual flanges, which allowed them to negotiate tighter curves without binding. The driving wheels on express passenger locomotives have come down in diameter over the years, e.g. from 8 ft 1 in on the GNR Stirling 4-2-2 of 1870 to 6 ft 2 in on the SR Merchant Navy Class of 1941. This is. On locomotives with side rods, including most steam and jackshaft locomotives, the driving wheels have weights to balance the weight of the coupling and connecting rods; the crescent-shaped balance weight is visible in the picture on the right. In the Whyte notation, driving wheels are designated by numbers in the set; the UIC classification system counts the number of axles rather than the number of wheels and driving wheels are designated by letters rather than numbers. The suffix'o' is used to indicate independently powered axles; the number of driving wheels on locomotives varied quite a bit. Some early locomotives had as few as two driving wheels; the largest number of total driving wheels was 24 on the 2-8-8-8-4 locomotives.
The largest number of coupled driving wheels was 14 on the ill-fated AA20 4-14-4 locomotive. The term driving wheel is sometimes used to denote the drive sprocket which moves the track on tracked vehicles such as tanks and bulldozers. Many American roots artists, such as The Byrds, Tom Rush, The Black Crowes and the Canadian band Cowboy Junkies have performed a song written by David Wiffen called "Driving Wheel", with the lyrics "I feel like some old engine/ That's lost my driving wheel."These lyrics are a reference to the traditional blues song "Broke Down Engine Blues" by Blind Willie McTell, 1931. It was directly covered by Bob Dylan and Johnny Winter. Many versions of the American folk song "In the Pines" performed by artists such as Leadbelly, Mark Lanegan, Nirvana reference a decapitated man's head found in a driving wheel. In addition, it is that Chuck Berry references the locomotive driving wheel in "Johnny B. Goode" when he sings, "the engineers would see him sitting in the shade / Strumming with the rhythm that the drivers made."
The volt is the derived unit for electric potential, electric potential difference, electromotive force. It is named after the Italian physicist Alessandro Volta. One volt is defined as the difference in electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points, it is equal to the potential difference between two parallel, infinite planes spaced 1 meter apart that create an electric field of 1 newton per coulomb. Additionally, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it, it can be expressed in terms of SI base units as V = potential energy charge = J C = kg ⋅ m 2 A ⋅ s 3. It can be expressed as amperes times ohms, watts per ampere, or joules per coulomb, equivalent to electronvolts per elementary charge: V = A ⋅ Ω = W A = J C = eV e; the "conventional" volt, V90, defined in 1987 by the 18th General Conference on Weights and Measures and in use from 1990, is implemented using the Josephson effect for exact frequency-to-voltage conversion, combined with the caesium frequency standard.
For the Josephson constant, KJ = 2e/h, the "conventional" value KJ-90 is used: K J-90 = 0.4835979 GHz μ V. This standard is realized using a series-connected array of several thousand or tens of thousands of junctions, excited by microwave signals between 10 and 80 GHz. Empirically, several experiments have shown that the method is independent of device design, measurement setup, etc. and no correction terms are required in a practical implementation. In the water-flow analogy, sometimes used to explain electric circuits by comparing them with water-filled pipes, voltage is likened to difference in water pressure. Current is proportional to the amount of water flowing at that pressure. A resistor would be a reduced diameter somewhere in the piping and a capacitor/inductor could be likened to a "U" shaped pipe where a higher water level on one side could store energy temporarily; the relationship between voltage and current is defined by Ohm's law. Ohm's Law is analogous to the Hagen–Poiseuille equation, as both are linear models relating flux and potential in their respective systems.
The voltage produced by each electrochemical cell in a battery is determined by the chemistry of that cell. See Galvanic cell § Cell voltage. Cells can be combined in series for multiples of that voltage, or additional circuitry added to adjust the voltage to a different level. Mechanical generators can be constructed to any voltage in a range of feasibility. Nominal voltages of familiar sources: Nerve cell resting potential: ~75 mV Single-cell, rechargeable NiMH or NiCd battery: 1.2 V Single-cell, non-rechargeable: alkaline battery: 1.5 V. Some antique vehicles use 6.3 volts. Electric vehicle battery: 400 V when charged Household mains electricity AC: 100 V in Japan 120 V in North America, 230 V in Europe, Asia and Australia Rapid transit third rail: 600–750 V High-speed train overhead power lines: 25 kV at 50 Hz, but see the List of railway electrification systems and 25 kV at 60 Hz for exceptions. High-voltage electric power transmission lines: 110 kV and up Lightning: Varies often around 100 MV.
In 1800, as the result of a professional disagreement over the galvanic response advocated by Luigi Galvani, Alessandro Volta developed the so-called voltaic pile, a forerunner of the battery, which produced a steady electric current. Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver. In 1861, Latimer Clark and Sir Charles Bright coined the name "volt" for the unit of resistance. By 1873, the British Association for the Advancement of Science had defined the volt and farad. In 1881, the International Electrical Congress, now the International Electrotechnical Commission, approved the volt as the unit for electromotive force, they made the volt equal to 108 cgs units of voltage
Emmen is a municipality and town of the province Drenthe in the northeastern Netherlands. A prime example of a planned city, Emmen arose from several small farming and peat-harvesting communities which have dotted the province of Drenthe since the Middle Ages. Traces of these communities can still be seen in the form of the villages of Westenesch and Zuidbarge: they have a separate history and layout, but are surrounded by the suburbs and the centre of Emmen; the expansion of the town did not happen until after the Second World War. Suburbs were built around the old centre of Emmen, starting with Emmermeer directly to the north, followed to the south-east by Angelslo, Emmerhout to the east, the Rietlanden and Parc Sandur to the south and south-west. Construction of the last suburb, called Delftlanden, is well underway with a large number of homes built and people living in the area. There are few historic landmarks left within the town, but those few include the church on the market square, where a church has been standing since the Middle Ages, the court of law building, dating from the beginning of the twentieth century, the post office from the same time.
In the town's environs an earthwork by Robert Smithson, "Broken Circle/Spiral Hill", may be found. In 1957 it hosted the 1st Women's Chess Olympiad; the prime economic booster since the 1980s has been the Dierenpark Emmen. Begun in the 1930s, it was completely redesigned in the 1970s, is now co-owned by the municipality of Emmen, it attracts over 1.5 million visitors per year. It was replaced by Wildlands in 2016. Important industries include Teijin Aramid, DSM Engineering Plastics and Diolen Industrial Fibers. There are extensive glasshouse complexes for horticulture in the Klazienaveen-Erica area; the municipality offers some 38,000 jobs. Emmen is the most populous urban area of Drenthe; the municipality of Emmen is one of the largest in the Netherlands, although the area outside the town borders of Emmen is rather rural. The other villages of importance are Emmer-Compascuum, Nieuw-Amsterdam and Schoonebeek; the population centres: The municipality of Emmen has some 107,000 inhabitants, with 56,000 living in the city of Emmen.
Compared to some 3,000 inhabitants in the nineteenth century, this illustrates the rapid growth of Emmen in the past 150 years. The town's football club FC Emmen plays their home games in De Oude Meerdijk, they play in the Eredivisie. Every year a big cycle racing criterium called Gouden Pijl, where all the big names in bicycle sport come to Emmen for this event. Besides the bicycle race itself the Gouden Pijl includes cultural events like pop-concerts etc. In 2008 the comeback concert of The Schizo's, the infamous local punk-band from the 1980s, was organised during the Gouden Pijl. Speedway Emmen hosts regular Stock Car and Banger Racing Emmen is served by one train connection with Zwolle, which in turn leads to the rest of the country. Emmen railway station Emmen Zuid railway station Nieuw Amsterdam railway stationIn addition, there are regular and frequent bus lines within Emmen and towards Groningen and Assen, as well as the surrounding countryside, Meppen in Germany, departing from Emmen's two bus terminals.
By car, the town is accessible via the N34 from Ommen via Hardenberg and Coevorden towards Emmen, ending at the A28 motorway towards Groningen near de Punt, the N381 to Drachten, the N391 to Veendam which goes through Emmen and the A37 from Hoogeveen to Meppen in Germany, although this motorway is not directly next to Emmen. From the A37 to Emmen there are three possibilities: at Junction Holsloot, at Highway-exit Schoonebeek, Highway-exit Klazienaveen; the A37 is the quickest way towards the Randstad from Emmen. The A37 ends at the German border, where it continues as the B402 or European route E233; the nearest airport is Groningen Airport Eelde at a distance of 50 kilometers. Furthermore, there are inland shipping connections via Nieuw-Amsterdam to Coevorden and Almelo. Official website Emmen travel guide from Wikivoyage
Electric current collectors are used by trolleybuses, electric locomotives or EMUs to carry electrical power from overhead lines or electrical third rails to the electrical equipment of the vehicles. Those for overhead wires are roof-mounted devices, those for third rails are mounted on the bogies, they have one or more spring-loaded arms that press a collector or contact shoe against the rail or overhead wire. As the vehicle moves, the contact shoe slides along the wire or rail to draw the electricity needed to run the vehicle's motor; the current collector arms are electrically conductive but mounted insulated on the vehicle's roof, side or base. An insulated cable connects the collector with the transformer or motor; the steel rails of the tracks act as the electrical return. Electric vehicles that collect their current from an overhead line system use different forms of one- or two-arm pantograph collectors, bow collectors or trolley poles; the current collection device presses against the underside of the lowest wire of an overhead line system, called a contact wire.
Most overhead supply systems are either DC or single phase AC, using a single wire with return through the grounded running rails. Three phase AC systems use a pair of overhead wires, paired trolley poles. Electric railways with third rails, or fourth rails, in tunnels carry collector shoes projecting laterally, or vertically, from their bogies; the contact shoe may slide on the bottom or on the side. The side running contact shoe is used against the guide bars on rubber-tired metros. A vertical contact shoe is used on ground-level power supply systems, stud contact systems and fourth rail systems. A pair of contact shoes was used on underground current collection systems; the contact shoe on a stud contact system is called a ski collector. The ski collector moves vertically to accommodate slight variations in the height of the studs. Contact shoes may be used on overhead conductor rails, on guide bars or on trolley wires. Most railways use three rails. TRUCK
Amersfoort is a city and municipality in the province of Utrecht, Netherlands. In August 2017, the municipality had a population of 155,089, making it the second-largest of the province and fifteenth-largest of the country. Amersfoort is one of the largest Dutch railway junctions with its three stations—Amersfoort and Vathorst—due to its location on two of the Netherlands' main east to west and north to south railway lines; the city was used during the 1928 Summer Olympics as a venue for the modern pentathlon events. Amersfoort marked its 750th anniversary as a city in 2009; the municipality of Amersfoort consists of the following cities, towns and districts: Bergkwartier, Binnenstad, Hoogland-West, Kruiskamp, de Koppel, Rustenburg, Randenbroek, Schothorst, Vathorst, Vermeerkwartier, Leusderkwartier and Stoutenburg-Noord. Hunter gatherers set up camps in the Amersfoort region in the Mesolithic period. Archaeologists have found traces of these camps, such as the remains of hearths, sometimes microlithic flint objects, to the north of the city.
Remains of settlements in the Amersfoort area from around 1000 BC have been found, but the name Amersfoort, after a ford in the Amer River, today called the Eem, did not appear until the 11th century. The city grew around what is now known as the central square, the Hof, where the Bishops of Utrecht established a court in order to control the "Gelderse Vallei" area, it was granted city rights in 1259 by the bishop of Henry I van Vianden. A first defensive wall, made out of brick, was finished around 1300. Soon after, the need for enlargement of the city became apparent and around 1380 the construction of a new wall was begun and completed around 1450; the famous Koppelpoort, a combined land and water gate, is part of this second wall. The first wall was demolished and houses were built in its place. Today's Muurhuizen Street is at the exact location of the first wall; the Onze-Lieve-Vrouwentoren is one of the tallest medieval church towers in the Netherlands at 98 metres. The construction of the tower and the church was started in 1444.
The church was destroyed by an explosion in 1787, but the tower survived, the layout of the church still can be discerned today through the use of different types of stone in the pavement of the open space, created. It is now the reference point of the RD coordinate system, the coordinate grid used by the Dutch topographical service: the RD coordinates are; the inner city of Amersfoort has been preserved well since the Middle Ages. Apart from the Onze-Lieve-Vrouwetoren, the Koppelpoort, the Muurhuizen, there is the Sint-Joriskerk, the canal-system with its bridges, as well as medieval and other old buildings. In the Middle Ages, Amersfoort was an important centre for the textile industry, there were a large number of breweries. Jews lived in Amersfoort in the Middle Ages, before being expelled from the province in 1546 and beginning to return to the city in 1655; the nickname for Amersfoort, originates in the Amersfoortse Kei, a 9-tonne boulder, dragged from the Soest moors into the city in 1661 by 400 people because of a bet between two landowners.
The people got their reward when the winner pretzels. Other nearby towns nicknamed the people of Amersfoort Keientrekker; this story embarrassed the inhabitants, they buried the boulder in the city in 1672, but after it was found again in 1903 it was placed in a prominent spot as a monument. There are not many boulders in the Netherlands, so it can be regarded as an icon. One of the six Dutch towns established in the 17th Century in what is now Brooklyn was called "Nieuw Amersfoort"; the original patentees were Andries Hudde. Unlike other Dutch names which were retained up to the present, Nieuw Amersfoort is now called "Flatlands". In the 18th century the city flourished because of the cultivation of tobacco, but from about 1800 onwards began to decline; the decline was halted by the establishment of the first railway connection in 1863, some years by the building of a substantial number of infantry and cavalry barracks, which were needed to defend the western cities of the Netherlands. After the 1920s growth stalled again, until in 1970 the national government designated Amersfoort numbering some 70,000 inhabitants, as a "growth city".
Since Amersfoort was the largest garrison town in the Netherlands before the outbreak of the Second World War, with eight barracks, part of the main line of defence, the whole population of 43,000 was evacuated at the start of the invasion by the Germans in May 1940. After four days of battle, the population was allowed to return. There was a functioning Jewish community in the town, at the beginning of the war numbering about 700 people. Half of them were deported and killed in Auschwitz and Sobibor. In 1943, the synagogue, dating from 1727, was damaged on the orders of the Nazi-controlled city government, it was restored and opened again after the war, has been served since by a succession of rabbis. There was a Nazi concentration camp near the city of Amersfoort during the war; the camp called Polizeiliches Durchgangslager Amersfoort, better known as Kamp Amersfoort, was located in the neighbouring municipality of Leusden. After the war the leader of the camp, Jos
Boxtel is a municipality and a town in the southern Netherlands. This is the origin of the Van Boxtel family; the town was the site of the Battle of Boxtel fought in September 1794 during the Flanders campaign. It is principally remembered as the first battle of the future Duke of Wellington. Boxtel Lennisheuvel Liempde Dutch Topographic map of Boxtel, March 2014. Bas van Erp, Paralympic wheelchair tennis medalist Michael van Gerwen, 3-time World Darts Champion Sam Feldt, DJ and producer José van Dijck, social media scholar Boxtel railway station Media related to Boxtel at Wikimedia Commons Official website