direct-linked+network

 

прямой пуск вращающегося электродвигателя
Пуск вращающегося электродвигателя путем непосредственного подключения его к питающей сети.
[ ГОСТ 27471-87]

EN

direct-on-line starting
across-the-line starting (US)
the process of starting a motor by connecting it directly to the supply at rated voltage
[IEV number 411-52-15]

FR

démarrage direct
mode de démarrage d'un moteur, consistant à lui appliquer directement sa pleine tension assignée
[IEV number 411-52-15]

Рис. ABB
Схема прямого пуска электродвигателя

Magnetic only circuit-breaker - Автоматический выключатель с электромагнитным расцепителем

Contactor KL - Контактор KL

Thermal relay - Тепловое реле

 

Параллельные тексты EN-RU

Direct-on-line starting

Direct-on-line starting, which is often abbreviated as DOL, is perhaps the most traditional system and consists in connecting the motor directly to the supply network, thus carrying out starting at full voltage.

Direct-on-line starting represents the simplest and the most economical system to start a squirrel-cage asynchronous motor and it is the most used.

As represented in Figure 5, it provides the direct connection to the supply network and therefore starting is carried out at full voltage and with constant frequency, developing a high starting torque with very reduced acceleration times.

The typical applications are relevant to small power motors also with full load starting.

These advantages are linked to some problems such as, for example, the high inrush current, which - in the first instants - can reach values of about 10 to 12 times the rated current, then can decrease to about 6 to 8 times the rated current and can persist to reach the maximum torque speed.

The effects of such currents can be identified with the high electro-dynamical stresses on the motor connection cables and could affect also the windings of the motor itself; besides, the high inrush torques can cause violent accelerations which stress the transmission components (belts and joints) generating distribution problems with a reduction in the mechanical life of these elements.

Finally, also the possible electrical problems due to voltage drops on the supply line of the motor or of the connected equipment must be taken into consideration.
[ABB]

Прямой пуск

Прямой пуск, который по-английски часто сокращенно обозначают как DOL, является, пожалуй наиболее распространенным способом пуска. Он заключается в непосредственном (т. е. прямом) подключении двигателя к питающей сети. Это означает, что пуск двигателя осуществляется при полном напряжении.

Схема прямого пуска является наиболее простым, экономичным и чаще всего применяемым решением для электродвигателей с короткозамкнутым ротором.

Схема прямого подключения к сети представлена на рисунке 5. Пуск осуществляется при полном напряжении и постоянной частоте сети. Электродвигатель развивает высокий пусковой момент при коротком времени разгона.

Типичные области применения – маломощные электродвигатели, в том числе с пуском при полной нагрузке.

Однако, наряду с преимуществами имеются и определенные недостатки, например, бросок пускового тока, достигающий в первоначальный момент 10…12-кратного значения от номинального тока электродвигателя. Затем ток двигателя уменьшается примерно до 6…8-кратного значения номинального тока и будет держаться на этом уровне до тех пор, пока скорость двигателя не достигнет максимального значения.

Такое изменение тока оказывает значительное электродинамическое воздействие на кабель, подключенный к двигателю. Кроме того пусковой ток воздействует на обмотки двигателя. Высокий начальный пусковой момент может привести к значительному ускорению и следовательно к значительной нагрузке элементов привода (ремней, крепления узлов), что вызывает сокращение их срока службы.

И, наконец, следует принять во внимание возможное возникновение проблем, связанных с падением напряжения в линии питания двигателя и подключенного к этой линии оборудования.
[Перевод Интент]

 

Тематики

• машины электрические вращающиеся в целом
• управление электродвигателями
• электродвигатель асинхронный

Синонимы

• прямой пуск

EN

• across-the-line starting (US)
• direct line starting
• direct operation of a motor
• direct starting
• direct-on-line starting
• DOL
• full voltage starter application

DE

• Anlauf mit direktem Einschalten

FR

• démarrage direct

SUBJECT AREA: Land transport, Railways and locomotives

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George Stephenson was the son of the fireman of the pumping engine at Wylam colliery, and horses drew wagons of coal along the wooden rails of the Wylam wagonway past the house in which he was born and spent his earliest childhood. While still a child he worked as a cowherd, but soon moved to working at coal pits. At 17 years of age he showed sufficient mechanical talent to be placed in charge of a new pumping engine, and had already achieved a job more responsible than that of his father. Despite his position he was still illiterate, although he subsequently learned to read and write. He was largely self-educated.

In 1801 he was appointed Brakesman of the winding engine at Black Callerton pit, with responsibility for lowering the miners safely to their work. Then, about two years later, he became Brakesman of a new winding engine erected by Robert Hawthorn at Willington Quay on the Tyne. Returning collier brigs discharged ballast into wagons and the engine drew the wagons up an inclined plane to the top of "Ballast Hill" for their contents to be tipped; this was one of the earliest applications of steam power to transport, other than experimentally.

In 1804 Stephenson moved to West Moor pit, Killingworth, again as Brakesman. In 1811 he demonstrated his mechanical skill by successfully modifying a new and unsatisfactory atmospheric engine, a task that had defeated the efforts of others, to enable it to pump a drowned pit clear of water. The following year he was appointed Enginewright at Killingworth, in charge of the machinery in all the collieries of the "Grand Allies", the prominent coal-owning families of Wortley, Liddell and Bowes, with authorization also to work for others. He built many stationary engines and he closely examined locomotives of John Blenkinsop's type on the Kenton \& Coxlodge wagonway, as well as those of William Hedley at Wylam.

It was in 1813 that Sir Thomas Liddell requested George Stephenson to build a steam locomotive for the Killingworth wagonway: Blucher made its first trial run on 25 July 1814 and was based on Blenkinsop's locomotives, although it lacked their rack-and-pinion drive. George Stephenson is credited with building the first locomotive both to run on edge rails and be driven by adhesion, an arrangement that has been the conventional one ever since. Yet Blucher was far from perfect and over the next few years, while other engineers ignored the steam locomotive, Stephenson built a succession of them, each an improvement on the last.

During this period many lives were lost in coalmines from explosions of gas ignited by miners' lamps. By observation and experiment (sometimes at great personal risk) Stephenson invented a satisfactory safety lamp, working independently of the noted scientist Sir Humphry Davy who also invented such a lamp around the same time.

In 1817 George Stephenson designed his first locomotive for an outside customer, the Kilmarnock \& Troon Railway, and in 1819 he laid out the Hetton Colliery Railway in County Durham, for which his brother Robert was Resident Engineer. This was the first railway to be worked entirely without animal traction: it used inclined planes with stationary engines, self-acting inclined planes powered by gravity, and locomotives.

On 19 April 1821 Stephenson was introduced to Edward Pease, one of the main promoters of the Stockton \& Darlington Railway (S \& DR), which by coincidence received its Act of Parliament the same day. George Stephenson carried out a further survey, to improve the proposed line, and in this he was assisted by his 18-year-old son, Robert Stephenson, whom he had ensured received the theoretical education which he himself lacked. It is doubtful whether either could have succeeded without the other; together they were to make the steam railway practicable.

At George Stephenson's instance, much of the S \& DR was laid with wrought-iron rails recently developed by John Birkinshaw at Bedlington Ironworks, Morpeth. These were longer than cast-iron rails and were not brittle: they made a track well suited for locomotives. In June 1823 George and Robert Stephenson, with other partners, founded a firm in Newcastle upon Tyne to build locomotives and rolling stock and to do general engineering work: after its Managing Partner, the firm was called Robert Stephenson \& Co.

In 1824 the promoters of the Liverpool \& Manchester Railway (L \& MR) invited George Stephenson to resurvey their proposed line in order to reduce opposition to it. William James, a wealthy land agent who had become a visionary protagonist of a national railway network and had seen Stephenson's locomotives at Killingworth, had promoted the L \& MR with some merchants of Liverpool and had carried out the first survey; however, he overreached himself in business and, shortly after the invitation to Stephenson, became bankrupt. In his own survey, however, George Stephenson lacked the assistance of his son Robert, who had left for South America, and he delegated much of the detailed work to incompetent assistants. During a devastating Parliamentary examination in the spring of 1825, much of his survey was shown to be seriously inaccurate and the L \& MR's application for an Act of Parliament was refused. The railway's promoters discharged Stephenson and had their line surveyed yet again, by C.B. Vignoles.

The Stockton \& Darlington Railway was, however, triumphantly opened in the presence of vast crowds in September 1825, with Stephenson himself driving the locomotive Locomotion, which had been built at Robert Stephenson \& Co.'s Newcastle works. Once the railway was at work, horse-drawn and gravity-powered traffic shared the line with locomotives: in 1828 Stephenson invented the horse dandy, a wagon at the back of a train in which a horse could travel over the gravity-operated stretches, instead of trotting behind.

Meanwhile, in May 1826, the Liverpool \& Manchester Railway had successfully obtained its Act of Parliament. Stephenson was appointed Engineer in June, and since he and Vignoles proved incompatible the latter left early in 1827. The railway was built by Stephenson and his staff, using direct labour. A considerable controversy arose c. 1828 over the motive power to be used: the traffic anticipated was too great for horses, but the performance of the reciprocal system of cable haulage developed by Benjamin Thompson appeared in many respects superior to that of contemporary locomotives. The company instituted a prize competition for a better locomotive and the Rainhill Trials were held in October 1829.

Robert Stephenson had been working on improved locomotive designs since his return from America in 1827, but it was the L \& MR's Treasurer, Henry Booth, who suggested the multi-tubular boiler to George Stephenson. This was incorporated into a locomotive built by Robert Stephenson for the trials: Rocket was entered by the three men in partnership. The other principal entrants were Novelty, entered by John Braithwaite and John Ericsson, and Sans Pareil, entered by Timothy Hackworth, but only Rocket, driven by George Stephenson, met all the organizers' demands; indeed, it far surpassed them and demonstrated the practicability of the long-distance steam railway. With the opening of the Liverpool \& Manchester Railway in 1830, the age of railways began.

Stephenson was active in many aspects. He advised on the construction of the Belgian State Railway, of which the Brussels-Malines section, opened in 1835, was the first all-steam railway on the European continent. In England, proposals to link the L \& MR with the Midlands had culminated in an Act of Parliament for the Grand Junction Railway in 1833: this was to run from Warrington, which was already linked to the L \& MR, to Birmingham. George Stephenson had been in charge of the surveys, and for the railway's construction he and J.U. Rastrick were initially Principal Engineers, with Stephenson's former pupil Joseph Locke under them; by 1835 both Stephenson and Rastrick had withdrawn and Locke was Engineer-in-Chief. Stephenson remained much in demand elsewhere: he was particularly associated with the construction of the North Midland Railway (Derby to Leeds) and related lines. He was active in many other places and carried out, for instance, preliminary surveys for the Chester \& Holyhead and Newcastle \& Berwick Railways, which were important links in the lines of communication between London and, respectively, Dublin and Edinburgh.

He eventually retired to Tapton House, Chesterfield, overlooking the North Midland. A man who was self-made (with great success) against colossal odds, he was ever reluctant, regrettably, to give others their due credit, although in retirement, immensely wealthy and full of honour, he was still able to mingle with people of all ranks.

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