Problem: Historically, AC motors were used for single or double speed elevator machines on the grounds of cost and lower usage applications where car speed and passenger comfort were less of an issue, but for higher speed, larger capacity elevators, the need for infinitely variable speed control over the traction machine becomes an issue. Therefore, DC machines powered by an AC/DC motor generator were the preferred solution. The MG set also typically powered the relay controller of the elevator, which has the added advantage of electrically isolating the elevators from the rest of a building's electrical system, thus eliminating the transient power spikes in the building's electrical supply caused by the motors starting and stopping (causing lighting to dim every time the elevators are used for example), as well as interference to other electrical equipment caused by the arcing of the relay contactors in the control system.
Generally, what powered the relay contoller?
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Answer: MG set

Problem: The first attempt to establish a proper governing body and adopted the current set of Rugby rules was the Foot Ball Association of Canada, organized on March 24, 1873 followed by the Canadian Rugby Football Union (CRFU) founded June 12, 1880, which included teams from Ontario and Quebec. Later both the Ontario and Quebec Rugby Football Union (ORFU and QRFU) were formed (January 1883), and then the Interprovincial (1907) and Western Interprovincial Football Union (1936) (IRFU and WIFU). The CRFU reorganized into an umbrella organization forming the Canadian Rugby Union (CRU) in 1891. The original forerunners to the current Canadian Football League, was established in 1956 when the IRFU and WIFU formed an umbrella organization, The Canadian Football Council (CFC). And then in 1958 the CFC left The CRFU to become The CFL.
When were the ORFU and the CRU formed?
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Answer: unanswerable

Problem: In Germany, practical reference works intended for the uneducated majority became popular in the 18th century. The Marperger Curieuses Natur-, Kunst-, Berg-, Gewerkund Handlungs-Lexicon (1712) explained terms that usefully described the trades and scientific and commercial education. Jablonksi Allgemeines Lexicon (1721) was better known than the Handlungs-Lexicon, and underscored technical subjects rather than scientific theory. For example, over five columns of text were dedicated to wine, while geometry and logic were allocated only twenty-two and seventeen lines, respectively. The first edition of the Encyclopdia Britannica (1771) was modelled along the same lines as the German lexicons.
Was the Jablonski Allgemeines Lexicon (1721) more dedicated to technical subjects or scientific theory?
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Answer:
technical subjects