Kálmán Kandó

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Kandó triangle drive The propulsive force was transferred to the locomotive's wheels using a traditional pushrod system, designed to provide manufacturing and maintenance commodity to the predominantly steam-based Hungarian Railways (MÁV) of the time. The so-called Kandó triangle arrangement transferred power from the electric motor to the pushrods in such a way that no oblique forces were exerted on the chassis, making the V40 less hurtful to the rail track compared to steam engines. In practice the V40 pushrod system was too precise for steam-era habits based maintenance and required more frequent care.

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Kálmán

Kálmán Kandó de Egerfarmos et Sztregova (egerfarmosi és sztregovai Kandó Kálmán; July 10, 1869 – January 13, 1931) was a Hungarian engineer, the inventor of phase converter and a pioneer in the development of AC electric railway traction.

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Education and Family Kálmán Kandó was born on July 8, 1869, in Pest into an ancient Hungarian noble family. His father was Géza Kandó (1840-1906) and his mother was Irma Gulácsy (1845-1933). He began his grammar school studies at the Budapest Lutheran High School in Sütő street. His parents transferred him from a crowded school to a smaller school, a practice grammar school founded by Mór Kármán. He was enrolled in Budapest Technical University. In 1892, he received a degree in mechanical engineering. He completed his studies with excellent qualifications. Kandó served as a volunteer in the Austro-Hungarian Navy until 1893. He married Ilona Mária Petronella Posch (1880-1913) in Terézváros on February 2, 1899. Their first child, also named Kálmán was born in the winter of 1899, and their daughter Ilona Sára was born in 1901. On July 9, 1913, his wife died of renal failure in Rozsnyó. His son Kálmán became a military officer. On October 18, 1922, his son Kálmán committed suicide with a service pistol (under unclear circumstances) in a military barrack. His daughter Ilona Mária was married on July 7, 1923, and his grandson, George (also an engineer), was born on June 5, 1924.

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France After his military service, he traveled to France in the autumn of 1893, and worked for the Fives-Lille Company as a junior engineer, where he designed and developed early induction motors for locomotives. For the manufacture of induction motors, he developed a completely new design-calculation procedure, which made it possible to produce economical AC traction motors for the Fives Lille Company. Kandó designed more suitable 3-phase asynchronous electric drive motors instead of the less effective synchronous electric motors of earlier locomotive designs. Within a year, Kandó was appointed as the chief engineer of the electric motor development at the French firm. András Mechwart (the Ganz and Co.’s managing director at that time) asked him to return to Hungary in 1894 and invited him to work at the electrical engineering department of the Ganz Works.

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Ganz Company, Budapest In 1894, Kálmán Kandó developed high-voltage three phase alternating current motors and generators for electric locomotives; he is known as the father of the electric train. His work on railway electrification was done at the Ganz electric works in Budapest. Kandó's early 1894 designs were first applied in a short three-phase AC tramway in Evian-les-Bains (France), which was constructed between 1896 and 1898. It was driven by 37 HP asynchronous traction system. In 1907, he moved with his family to Vado Ligure in Italy and obtained employment with Società Italiana Westinghouse. He would later return to Budapest to work at the Ganz factory where he became the managing director.

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In 1897, Kandó designed an electric system and engines for the Italian railways, the electric traction system had great advantages and importance on the very steep railway tracks in the mountainous regions of Italy. Under his leadership, the Ganz factory began work on three-phase haulage for railways. Based on their design, the Italian Ferrovia della Valtellina was electrified in 1902 and became Europe's first electrified main line railway. For the Valtellina line, three-phase power was supplied at 3,000 volts (later increased to 3,600 volts) through two overhead lines, while the running rails supplied the third phase. At junctions, the two overhead lines had to cross and this prevented the use of very high voltages. The three-phase, two wire, system was used on several railways in Northern Italy and became known as "the Italian system". There are now few railways which use this system. In 1907, the Italian government decided for the electrification of another 2000-km railway line with the restriction that the electrical equipment and rolling stock could only be manufactured in Italy. The Westinghouse Company bought up Kandó's patents and paid a license-fee for the electric motors of the Ganz factory. The Westinghouse Company also built a locomotive factory…Citește mai mult

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Electrification of the London underground lines, a moral victory On the District and Metropolitan Railways, the use of steam locomotives led to smoke-filled stations and carriages that were unpopular with passengers and by the early twentieth century electrification was seen as the way forward. A tender was announced for an electric system, and the largest European and American companies applied to win the tender. However, when the experts of the railways compared the designs from the Ganz Works to the offers of the other large European and American competitors, they concluded that Ganz Works' technology was cheaper and more reliable and described its technology as a "revolution in electric railway traction". In 1901, a metropolitan and district joint committee recommended the Ganz three-phase AC system with overhead wires. Initially, this was unanimously accepted by both parties, until the district found an investor, the American Charles Yerkes, to finance the upgrade. Yerkes raised £1 million (1901 pounds adjusted by inflation are £106 million) and soon had control of the District Railway. However Yerkes favoured the classic DC system, similar to that in use on the City & South London Railway and Central London Railway. The Metropolitan Railway protested about the change…Citește mai mult

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Vienna, invention of the phase converter During World War I, between 1916 and 1917, Kandó was a lieutenant completing military service for the Ministry of Defence in Vienna. He worked out a revolutionary system of phase-changing electrical hauling, whereby locomotives were powered by the standard, 50-period, single-phase alternating current used in the national energy supply system. He was the first who recognised that an electric train system can only be successful if it can use the electricity from public networks. In 1918, Kandó invented and developed the rotary phase converter, enabling electric locomotives to use three-phase motors whilst supplied via a single overhead wire, carrying the simple industrial frequency (50 Hz) single phase AC of the high voltage national networks.

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To avoid the problems associated with the use of two overhead wires, Kandó developed a modified system for use in Hungary. Power semiconductors not having been invented yet in the 1930s, the Kandó V40 locomotives' systems relied on electromechanics and electrochemistry.

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Single-phase power was supplied at 16,000 volts and 50 Hz through a single overhead line and converted to three-phase on the locomotive by a rotary phase converter. The drive motors, made by Metropolitan-Vickers, had a very large diameter of 3 meters and incorporated four sets of 24 magnetic poles each, which could be added to the traction effort at will, producing highly efficient constant speeds of 25, 50, 75 and 100 km/h over rail (or 17/34/51/68 km/h for the V60 heavy freight train engine variant, which had six pairs of smaller driving wheels).

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He created an electric machine called a synchronous phase converter, which was a single-phase synchronous motor and a three-phase synchronous generator with common stator and rotor. It had two independent windings:

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The outer winding is a single-phase synchronous motor. The motor takes the power from the overhead line. The inner winding is a three-phase (or variable-phase) synchronous generator, which provides the power for the three- (or more) phase traction motors. The MÁV company decided to electrify the 190 km long Budapest-Hegyeshalom main line with a new "Kandó system". The system was fed from a three-phase 110 kV transmission line from the Bánhida power station, which had been commissioned in 1930, via a single-phase 16 kV 50 Hz overhead line converted at four transformer stations. Of the four line sections, two are connected to the same phase and the other two are loaded to the other phase. This means that the railway, despite the single-phase supply, still provides a roughly symmetrical load for the power plant. The transformer substations were simple, cheap and with excellent efficiency. The distance between substations was greater than any other system (35–40 km). On an experimental basis, the substation at Torbágy was switched off and the feed was taken over by the substation at Banhida. Even so, uninterrupted service could be maintained for 74 km distance from the feeder. The line, applied his phase-change system, was electrified…Citește mai mult

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V40 Engine details The greatest challenge was the creation of a locomotive capable of operating on a 50-cycle power supply. The first prototype locomotive was built in 1913 and underwent modifications based on operational experience. Test runs were conducted on the Budapest-Alag trial line. These experiments led to the development of the V40 series phase-shifting locomotive, also known as the Kandó locomotive. It had a power output of 2500 horsepower. The 16 kV, single-phase current taken from the overhead line was directly supplied to the primary winding of the phase shifter through the pantograph and the main switch. The phase shifter was an innovative solution that was ahead of its time. This was an extremely complex electrical machine. Its primary winding was located in the stator. This winding, along with the rotor excited by direct current, functioned as a single-phase synchronous motor. The rotor, located in the slots of the stator cores, induced 3, 4, or 6-phase voltages according to the switching sequence. Therefore, the secondary winding forms a multi-phase generator with the rotor. Thus, the phase shifter combines a single-phase synchronous motor and a multi-phase generator in one machine. Noteworthy is the water cooling system integrated into the windings…Citește mai mult

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Power factor A major benefit of this arrangement was a power factor of nearly 1.00 in the catenary-attached equipment, which fulfilled the electric powerplants' strict load-distributing regulations. The unacceptably poor power factor of pre-World War II design electric motors (occasionally as low as 0.65) was not felt outside the Kando locomotives, as the phase changer machinery provided isolation.

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Speed control Intermediate speeds were maintained by connecting a water and saltpeter based adjustable resistor to the line, which reduced the efficiency of the locomotive. Timetables for electrified lines were supposed to allow use of full efficiency constant speeds most of the time but, in practice, the need to share the track with trains hauled by MÁV Class 424 steam locomotives meant the water-hungry and wasteful "gearbox resistor" had to be used often.