Автоматизация подъема при скипах с донной разгрузкой в период замедления может быть осуществлена применением режима динамического торможения асинхронного подъемного двигателя. На рис. 1 расчетная диаграмма скорости в период замедления t 3 изображена пунктирной линией λр. В период разгрузки t 4 ' предположена постоянная скорость v 3 (линия рφ), которая в течение периода t 4 "падает до нуля по линии ϕѱ. Согласно диаграмме усилий асинхронной машины, изображенной на рис. 2, разгон подъемного двигателя в период пуска происходит по ломаной линии BCDEFGHIKLT,варьирующей около заданного (расчетного) значения усилия F 1 как около среднего значения между крайними пределами F 1 ' и F 1 ". По окончании периода пуска наступает период полного хода, в течение которого движущее усилие следует за всеми изменениями статического усилия. В предположении статически неуравновешенной системы подъема статическое усилие, а следовательно, и движущее усилие, развиваемое двигателем, работающим на естественной характеристике R 2 , пусть изменяется от значения F' s 2 в начале периода полного хода (точка N')до величины F" s 2 в конце этого периода (точка N). По окончании периода полного хода наступает период замедления t 3 , в течение которого предположен тормозной режим, осуществляемый в виде динамического торможения. Асинхронная машина с двигательного режима на характеристике R 2 при скорости v н переводится на динамический режим путем переключения статора с переменного тока на постоянный.
Система динамического торможения в последнее время получила значительное распространение на каменноугольных шахтах применительно к наклонным подъемам в случаях, когда требуется производить спуск груза или людей с уменьшенной скоростью. По сравнению с режимом противотока динамическое торможение является более экономичным. В соответственных случаях динамическое торможение может также найти применение и при вертикальных подъемах.
In practice, it may be necessary to lower people down a mine shaft at a reduced speed compared to the full speed of lifting the load. This makes it necessary to use braking operations, which in practice are often carried out using a mechanical brake. However, prolonged operation of a mechanical brake is accompanied by undesirable phenomena: excessive heating and wear of the brake pads, which necessitates the use of cooling devices and frequent replacement of worn pads with new ones. Electric braking systems are free from these drawbacks, of which in the case under consideration both counter-current (counter-switching) and dynamic braking can be used. To be able to implement the counter-current mode, the lifting unit must be equipped with a load rheostat, which, compared to an ordinary starting rheostat, must be designed for longer operation. In addition, this rheostat must have additional sections with a correspondingly increased resistance to be able to obtain small braking moments. The main disadvantage of counter-current braking is its uneconomical nature, due to the significant consumption of energy from the network. As is known, the power consumed in the counter-current mode from the network depends on the magnitude of the braking torque and synchronous speed and does not depend on the actual speed of descent. The energy consumed from the network is inversely related to the speed of descent.
Для правильного функционирования подъемной установки прежде всего должно быть обеспечено исправное действие смазки главных подшипников, осуществляемой при помощи двух маслонасосов, из которых один рабочий, а другой запасной. Управление маслонасосами производится при помощи переключателя маслонасосов. После замыкания цепи катушки 1РП замкнется ее контакт 1РП и тем самым перекроет разомкнутый при рабочих положениях командо-контроллера контакт КК-0, обеспечивая замыкание цепи катушки 1РП до тех пор, пока эта цепь не будет разорвана конечным выключателем ЗВК, размыкаемым при окончании подъема соответственной клетью. При замкнутой цепи катушки реле 1РП окажется замкнутым контакт этого реле 1РП, находящийся в цепи катушек реверсивных контакторов В и И. В результате этого в данном месте получится замыкание цепи катушек указанных реверсивных контакторов.
The idea of using a hydroelectric drive for a mine hoist occurred to the author of this article in 1944. In order to implement it, at the author's suggestion and under his scientific supervision, research work was organized in 1945 at the Leningrad Mining Institute with the participation of Assoc. Prof. A. E. Maksimov as the person in charge. After receiving theoretical and experimental results of the study, the first hydroelectric hoisting machine in mining practice was implemented in 1947 by joint efforts of researchers from the Department of Mining Electrical Engineering of the Leningrad Mining Institute and a group of engineers. The operating principle of the hydroelectric drive is as follows. Between the constantly rotating electric motor and the machine-tool, in this case - the hoisting machine, a hydraulic link is inserted - a centrifugal fluid coupling, due to which, depending on the degree of filling of the fluid coupling with working fluid, it is possible to obtain various values of the lifting speed - from zero to maximum.
The author examines in detail 1) centrifugal fans: fan drive systems, fan control of electric drive units; 2) axial fans, fan drive systems and electric drive control of fan units.
In the section concerning the actuator, machines with a constant winding radius are considered, as they have received preferential distribution in the USSR. Along with the kinematics and dynamics of hoisting with ordinary cages, considerable attention is paid to hoisting with tipping vessels and skips with bottom unloading. It is necessary to note that when considering various hoisting modes, in some cases, instead of the corresponding references, some formulas are repeated, which serve to determine the forces and powers in similar conditions, while maintaining, however, the identity of the numbering of the said formulas. Such a system of presentation allows for more convenient calculations for the corresponding hoisting modes, without having to search for the necessary expressions in different places in the book. A special section of the book is devoted to the consideration of the kinematics and dynamics of lowerinh with three-period tachograms carried out during operation by ordinary cages. With regard to the drive and control of the hoisting machine, a study was made of the physics of the processes occurring in various hoisting modes, both simple and the most complex, based on the coordination of the kinematics and dynamics of hoisting with the mechanical characteristics of the hoisting motors of both systems, i.e. asynchronous and in the Leonard drive. The calculation side, illustrated with numerical examples, relates to the definition of elements of the kinematics and dynamics of hoisting, energy consumption for hoisting, efficiency of hoisting units, starting rotor resistances of asynchronous hoisting motors and acceleration relay settings during automation of the starting period, the power of the hoisting motors, as well as the power of individual machines that make up the converter unit in the Leonard system. In conclusion, it should be noted that the issues considered in the proposed work, which is the result of many years of research by the author in the field of electric mine hoisting, are presented mainly in his own original interpretation. F. Shklyarskii June 1943
November 2, 1944 marked the 70th anniversary of the birth of one of the largest specialists in the field of mining mechanics, Academician Alexander Petrovich German.
The initial data for determining the starting resistance in the case under consideration are the following values. The power and type of lifting motor, for which, based on the corresponding catalogs, in turn, can be found: a) the ratio of the breaking (maximum) torque to the rated torque b) the rated rotor voltage Enom; c) rated rotor current In; d) engine efficiency; f) synchronous Ps and nominal Pnom number of revolutions of the latter. Calculated starting torque values. 3) Values of static moment of resistance corresponding to the starting period. 4) The number of stages (sections) of the rotor rheostat. 5) Starting period t1 and the full period of the working cycle T, including pause θ, in relation to a given tachogram. According to the given graphical method for determining starting resistances, it is necessary first of all to construct the mechanical characteristics of the engine: natural, corresponding to the own resistance of the rotor winding, and artificial, caused by the inclusion of certain stages (sections) of starting resistances in the rotor circuit. For this purpose, it is necessary to set the limiting (maximum and minimum) values of fluctuations in the starting torque, varying around its calculated value.
Synchronous motors are currently started at both full and reduced voltage. 4 Regardless of the method used for starting a synchronous motor, the rotor of the latter, in addition to the excitation winding powered by a normally direct current, is also equipped with a short-circuited starting winding, which during the starting period turns the synchronous motor into an asynchronous one with a squirrel-cage rotor with the starting properties inherent in this motor. Both of these rotor windings, not being electrically connected to each other, during the start-up period represent, as it were, two independent secondary circuits participating in the creation of the torque developed by the engine. When the engine is running at full (synchronous) speed, the short-circuited starting winding plays the role of a damper winding. The synchronous motor can be started either at full or at reduced voltage. This article discusses the operations of automatic control of compressor units driven by a synchronous motor, which is started at full voltage; automatic protection of these installations from possible accidents is also provided.
Вполне точное определение отдельных параметров трехпериодной тахограммы рудничного подъема, как известно, имеет место при тахограмме, представляющей собою трапецию с прямолинейными боками. Ниже предлагаются точные методы определения элементов тахограммы для двух систем подъема, при наличии прямолинейных сторон для периода пуска t1, и соответственных криволинейных сторон для периода замедления t2. Точное определение отдельных элементов трехпериодной тахограммы возможно: 1) в случае прямолинейных ее сторон, соответствующих периодам пуска и замедления; 2) в случае наличия одной прямолинейной стороны, соответствующей периоду пуска, и другой, изменяемой по закону синуса или гиперболического синуса криволинейной стороны, соответствующей периоду замедления при обязательном условии, что искомым при этом является период пуска t1 .
The use of a motor-generator set with a flywheel (Ward-Leonard-Ilgner) as the main motor of a synchronous motor is dictated by the presence of a hydraulic coupling connecting the main motor shaft to the shaft on which the alternating voltage is located. Dynamo and flywheel installed. This clutch replaces the automatic flywheel slip controller, which operates at a constant speed of the synchronous main engine. This article describes the installation of a fluid coupling, as well as the idea of using it in a Ward-Leonard-Ilgner system with a synchronous main motor.
