Kálmán Kandó

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.

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 enrolled in Budapest Technical University where he received a degree in mechanical engineering in 1892.

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. 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. 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. 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 £) 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 of plan, but after arbitration by the Board of Trade the DC system was adopted.

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.

Hungary

To avoid the problems associated with the use of two overhead wires, Kandó developed a modified system for use in Hungary. His V40 series phase-shifting locomotives were intended for passenger and express train service. 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).

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.

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. 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.

Shaft drive More than a decade after Kandó's death two new, shaft-driven prototypes of his design were built by the Ganz company, to allow for 125 km/h traction speeds. The V44 electric locomotives proved too heavy for general use, owing to their 22 metric ton per axle rail load. Both vehicles were eventually destroyed in USAAF bombing raids in 1944, running only 16,000 kilometers overall.

Bogie-mounted motors After the second World War, a last series of electric phase-changer locomotives were built by the new communist government in Hungary. Owing to Cold War restrictions, the innovative V55 type, which used bogie-mounted motors, had to be constructed of domestic components entirely and suffered from reliability problems in their double-conversion phase-changer / frequency-changer propulsion system. (The traction motors of pre-WWII V40 and V60 locomotives were made in Britain by the Metropolitan-Vickers company, as part of an economic aid programme organized by Lord Rothermere.)

Preservation Currently one example of the V40, the V55 and the V60 locomotive each survives. They are preserved at the Budapest Railway History Park, but require restoration after decades of open air static display. If funding permits, the repaired V40 may return to the open track for "nostalgic service", with a semiconductor front-end added to its system for 25 to 16 kV AC down-step conversion.

France

Kandó designed in 1926 the 1.5 kV DC 2BB2 400 (:fr:2BB2 400) for the Paris-Orleans line which were the strongest DC locomotives in Europe at that time. The Ganz Works of Budapest, Hungary supplied these two locomotives, to the design of Kálmán Kandó.

United Kingdom 8 years after the death of Kandó, the engineering office of the Ganz Works won several British tenders, which were mostly based on Kandó's latest technology. British firms were entrusted with the implementation of these plans. There were plans to use the two-wire, three-phase, system on the Portmadoc, Beddgelert and South Snowdon Railway in Wales and the Metropolitan Railway in London but neither of these plans came to fruition due to the outbreak of WWII.

Death and legacy Kálmán Kandó died of unexpected heart failure in Budapest on January 13, 1931. In Budapest, the Kandó Kálmán Faculty of Electrical Engineering (formerly an independent technical college, now part of Óbuda University), also bears his name. The minor planet 126245 Kandókálmán was named after him.