Mikhail Dolivo-Dobrovolsky

The last decade was marked by XIXstoletiya developments in technology, which can be called a new industrial revolution. This revolution, all the consequences of which still has not yet been revealed, which has had a profound impact on the technology and the global economy has created the possibility of measles reconstruction of the power unit of the national economy on the basis of electrification and the widest possible implementation of electricity in technology.

This revolution is to introduce the practice of multi-phase, in particular a three-phase, alternating current, and therefore the practical resolution of the problem of electric power transmission over long distances.

Mikhail Dolivo-Dobrovolsky is the creator of the art three-phase alternating currents and the first who on the basis of this technique made it possible to transfer electrical energy from the place of its production to almost arbitrarily large distance to the place of consumption.

The name of the great electrical engineer, scientist and remarkable large designer of electrical machinery and apparatus belongs to the history of technology, and with it the history of human culture. On whatever side of the life and work of modern man we may pay attention - everywhere we see a direct or indirect result of the work Dolivo-Dobrovolsky.

His name will always be a symbol of tireless creative research engineer and profoundly revolutionary scientific thought. 1 Proceedings of it - a wonderful sample of the successful application of science data to the broadest practical purposes.

Mikhail Dolivo-Dobrovolsky was born January 3, 1862 in St. Petersburg in the family official. In 1872, MO Dolivo-Dobrovolsky family moved to Odessa, and he entered the Odessa School. Brilliantly graduated from a college course, he entered the Riga Polytechnic Institute, he decided to devote himself to the activities of a mechanical engineer.

His training in high school MO Dolivo-Dobrovolsky began in 1880 .; students at this time was very active politically, and MO Dolivo-Dobrovolsky was directly involved in the activities of student revolutionary circles. For participating in "riots", related to the events of March 1881 MO Dolivo-Dobrovolsky was excluded from the number of students without admission rights at any Russian institution of higher education. higher school doors at home close to the MO-Dobrovolsky Dolivo indefinitely, and it has remained one way out - go to one of the foreign senior technical schools.

At this time, electrical engineering has emerged as a separate new branch of art, and the works of our compatriots Yablochkov, Chikoleva Lodygina and received a number of promising and broad practical applications. Electrical engineering interested MO Dolivo-Dobrovolsky More at Riga Polytechnic Institute, and deciding where to move after the repression to which he was subjected in Russia, he stopped at the Darmstadt Higher Technical School.

Since the autumn of 1881 to 1884, M. Dolivo-Dobrovolsky studied at the Faculty of Mechanical Engineering in Darmstadt, specifically studying electrical engineering. Electrical Equipment of that time was, in fact, the technique of direct current. The scornful and skeptical attitude to the technique of alternating currents was then characteristic of the vast majority of electrical engineers.

By that time, it was only a few years since, as the PP Yablochkov failed to prove the feasibility and importance of using alternating current, in particular for feeding the famous "candles Yablochkov". Just there for the first lighting installations alternators, built under the strong influence of the electric lighting candles Yablochkov success.

This situation in the field of electrical engineering had an impact on the formulation of teaching electrical engineering and in training electrical engineers. High school educated youth then almost exclusively on the ideas generation and application of DC.

MO Dolivo-Dobrovolsky, outstanding engineering capacity which has already been said in the early student works perfectly learned DC and its application. On the last course in Darmstadt, he made quite a significant invention: he first proposed the starter circuit to shunt DC motor that had a direct and strong influence on the development of electric drive DC.

After graduating with top marks Darmstadt Higher Technical School, MO Dolivo-Dobrovolsky immediately got an opportunity to work as a designer in shortly before organized in Germany electrical Edison Company, later transformed into a company "Universal electricity company."

The enterprises of the concern MO Dolivo-Dobrovolsky has worked all his life, except for the period 1903- 1909 gg., Where he worked in Switzerland, and the period of 1914-1918., When he, as a Russian citizen, during World War II She left outside of Germany.

The first works MO Dolivo-Dobrovolsky as a practical engineer belonged to DC systems. Pursuing the development of practical problems in this field, MO Dolivo-Dobrovolsky fixed on the most important trends and developments of theoretical thought. He became known to the theoretical work of the Italian physicist and electrical engineer Galileo Ferraris on a rotating magnetic field in which it was stated that the two variables current, differing in phase by 90 °, can produce work in correspondingly arranged magnetic fields acting on and able to rotate a copper cylinder.

As you know, the idea of ​​Ferraris initially did not attract the attention of wide circles of electricians, especially since he Ferraris argued that efficiency in this method of producing mechanical work will not exceed 50%. Not passed the Ferraris of works by two young electrical engineer, who later gained international fame: the Serb Nikola Tesla and the Russian MO Dolivo-Dobrovolsky.

Tesla, based on the principle of the rotating magnetic field, built a two-phase generator and AC motor. His work has been reported in detail to the American Institute of Electrical Engineers in May 1888

He built two-phase electric cars do not contain any sliding contacts or commutator or collector. For their actions enough it was three wires instead of four. At the Niagara hydroelectric power plant, built in 1896, it has been installed this kind of two-phase alternators.

MO Dolivo-Dobrovolsky on their own, completely original, deep research came to the question of the theory and application of the rotating magnetic field. An examination of some phenomena in DC machines undertaken for quite different purposes, had no connection with the phenomenon of the rotating magnetic field, led him intuitively to recognize the falsity of conclusions Ferraris. It is assumed that the efficiency of electric motors operating on the principle of a rotating magnetic field can be significantly higher than 50%, and consequently so-called multiphase electric AC machine can receive a great practical importance.

Since 1888 MO Dolivo-Dobrovolsky began to study multiphase systems, for which it has established a special name, firmly established in the electrical terminology. MO Dolivo-Dobrovolsky has set itself the task of creating a rotating field is more perfect than the two-phase obtained and applied in their Tesla motors.

After some research, he built in 1888, the first three-phase AC generator power for about 3 kilowatts, which he brought into operation its first three-phase motor with a stator in the form of a ring Gram fed at three points, and the rotor in the form of a solid copper cylinder.

Further work led him to the construction of a three-phase motor with rotor from cast iron with added hollow copper cylinder. This rotor was better than the first; even more turned out to be perfect the next type of rotor - a squirrel cage.

Simultaneously, MO Dolivo-Dobrovolsky studied the star connection and the delta and experimented with various currents and voltages with machines having a different number of pole pairs. During the year, he allowed the principal problems associated with the construction of three-phase electric cars, and in 1889 the results of his labors were demonstrated in a pilot plant that plagues all electrical engineers for its small size with three-phase motor power given. There was the beginning of a new period in the development of the use of electricity for practical purposes, though not all recognize.

Among those who reacted with restraint to the results obtained it was TA Edison , visited MO Dolivo-Dobrovolsky in 1889 and immediately became acquainted with his three-phase system.

Triumph three-phase current system relates to 1891, when Frankfurt electrical exhibition was made a general test of the system in the form of a transfer of power from Lauffenskogo Falls to Frankfurt am Main (distance between "them - 175 km).

By this time the MO Dolivo-Dobrovolsky began to build a powerful three-phase asynchronous motors and built the first three-phase transformers. A few kilometers from Heilbronn on the river. Neckar, the birthplace of Robert Mayer, one of the creators of the law of conservation of energy, in the picturesque village Lauffene was a small cement plant, enjoyed for its energy needs waterfall on the river. Neckar. The plant would consume for their own needs only a small part of the received energy, and factory owners decided to use it at full scale by transferring in Heilbronn.

Experiments Marcel Deprez, produced in 1882 at the Munich exhibition of electrical, showed the fundamental possibility of such a transfer. But by 1890 equipment it received as a result of the works MO-Dobrovolsky Dolivo three-phase alternating current. With this new technical facility, it was decided to arrange the transfer of electricity from the nearby Lauffena not Heilbronn, and in Frankfurt.

This problem was brilliantly solved. Three-phase current voltage of 8500 volts could pass for 175 km of power at 300 horsepower with an efficiency of 77.4%. MO Dolivo-Dobrovolsky built for this plant raising and lowering three-phase transformers of their system and the asynchronous motor to its design.

Success MO Dolivo-Dobrovolsky has surpassed all expectations, and the three-phase alternating current became from that time all recognized and gradually occupied the dominant position in electrical engineering. a distance transmission of electrical energy gained his first practical solution at a sufficiently high level of efficiency, putting thus the beginning of solving complex problems within the broad concept of electrification.

At the Frankfurt Show 1891 MO Dolivo-Dobrovolsky managed to make another very important discovery: he found the increase in voltage at the generator terminals in an open Lauffene when the high-voltage line at Frankfurt. He gave a scientific explanation for this phenomenon, indicating that it is a generator armature reaction to the capacitive load, published on the occasion of a detailed article in 1891 MO Dolivo-Dobrovolsky belongs to many other works I inventions related to different areas of electrical engineering.

Thus, he three-wire DC car was built with an induction coil for the middle wire, a number of measurement of electrical appliances with soft iron phase meter with its original design and numerous other electrical devices and appliances.

List all of his inventions and improvements, without saving it in electrical engineering, which means not only to tell the story of the birth and development of three-phase power systems, but also affect the principal moments of the history of modern electrical engineering, among the founders of a MO-Dobrovolsky Dolivo belongs to the leading position.

It is interesting to note some of the features of creative methods MO Dolivo-Dobrovolsky. In all his works, he carefully, persistently to get down to the basic physical phenomena in a given process, using intuitive scientist widely-electrical and never resorting to mathematical analysis of phenomena. MO Dolivo-Dobrovolsky created for himself working hypotheses, and produced on the basis of their engineering calculations designs.

Completed his calculation on the basis of the design after testing and analysis of the results allowed MO Dolivo-Dobrovolsky opportunity to assess the correctness of his understanding of the essence of physical phenomena and suitability adopted a working hypothesis.

After MO Dolivo-Dobrowolski left theoretical work, but the calculation methods established by them, were always quite correct and did not lose its practical significance to our time.

MO Dolivo-Dobrovolsky put a lot of work for the promotion of scientific and technical three-phase alternating current applications. Through conversations, scientific debates, reports and monographs, he has achieved what he has in this case is not ideological opponents left.

Those who personally knew MO Dolivo-Dobrovolsky, show that he is serious about reasonable objections and was always ready to learn something useful that came from opponents. But unreasonable objections he treated with withering irony, breaking their opponents too dashing deeply sarcastic remarks, clothed with exceptionally correct external shape.

Among electricians, he was known as a disinterested adviser, who helped a lot with his advice to all, and especially for young engineers. In 1901, the organization of the St. Petersburg Polytechnic Institute, MO Dolivo-Dobrovolsky proposal was made to take it to the department of electrical engineering and, thus, lead the first Russian high school High electrical engineering.

The absence in the Russian electrical factories, where MO Dolivo-Dobrovolsky could continue their technical and design work and combine research and teaching activities with practical work, to keep him from accepting the invitation. Meanwhile, his relationship with German entrepreneurs, who he worked with were strictly official and even unfriendly; he has always maintained around the independence of judgment. In their proposal to abandon the Russian citizenship, he posted a sharp denial. At the announcement in 1914. War MO Dolivo-Dobrovolsky immediately went to Switzerland and until 1918 lived in the new emigration.

The last years of his life MO Dolivo-Dobrovolsky was busy thinking about power transmission over long distances using high voltage direct current. His views on this issue, he outlined in a detailed report, "On the limits of the power transmission possible over a distance alternating current" caused by an extremely lively, sharpens, even partly, an exchange of views.

In his report, MO Dolivo-Dobrovolsky pointed out that the transfer of energy over long distances, hundreds and thousands of kilometers, the effect of capacitance and self-inductance of the transmission line will limit the applicability of the alternating current for this purpose. Proving the benefits of underground cable networks to air for long-distance transmission, it is pointed out that in this case even more narrow the boundaries of applicability of the AC.

The future development of electrical MO Dolivo-Dobrovolsky seen in distant power DC high voltage underground cables. As you know, this issue has not lost its value and now, after more than three decades after the MO-Dolivo Dobrovolskiy pushed her; she again put on the agenda of both technically and economically feasible, and as a very important for the national economy. MO Dolivo-Dobrovolsky developed this question until the last days of his life.

His death that took place November 15, 1919 from heart disease, interrupted his work in full swing. MO Dolivo-Dobrovolsky was comprehensively educated and very cultured; it is difficult to indicate a deep human problems in which the discussion MO Dolivo-Dobrovolsky would not show the originality and depth of view. Here he came to the aid of an excellent knowledge of the world of literature and art. All who knew him noted in it not only the presence of a great mind, a solid character, but also a special warmth - properties inherent in truly outstanding people.

His death, like the death of remarkable technical progress activist, famous for major works, and man of exceptional spiritual purity, full-intentioned, was greeted with genuine sorrow engineers all over the world.

Source: People Russian Science: Essays on the prominent figures of science and technology / ed. SI Vavilov. - M., L .: State. publ tehn. theoretical literature. - 1948.

See also: Moritz von Jacobi (from the book by SI Vavilov, 1948)