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Proceedings of the Technical university of Sofia, 1995 -: Recent submissions

Now showing items 561-580 of 853

Title: Повишаване точността при определяне на електрическите характеристики на електродъгови пещи Author: Господинов, Васил Спасов Date: 1995 Abstract: To increase the accuracy when defining the electrical characteristics one must known actual values of the reactance of electric circuit of electrical arc furnaces. The suitable model of defining inductive reactance will be dissented in the article. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Оптимално отношение между активната и конструктивната маса в някои електромагнитни уреди Author: Русев, Димитър Симеонов; Rusev, Dimitar Simeonov Date: 1995 Abstract: In this paper the influence of the active mass (moveable ferromagnetic element) on the torque of electromagnetic measurement instruments with round coil and light opening is discussed. On this base the optimal relationship between active and constructive mass, providing maximum coefficient of mechanical quality factor is determined for various instruments. Library:
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Title: Метод на частичния разряд и приложението му при изпитване на нисковолтови електрически устройства Author: Колев, Николай Петков; Манолов, Емил Христов; Kolev, Nikolai Petkov; Manov, Emil Hristov Date: 1995 Abstract: The application of partial discharge for testing of low-voltage equipment (up to 1000 has significantly grown in the last year. In this paper the basic theoretical statements and measurement structures for partial discharge testing are discussed. The possibilities fin-designing of intelligent measurement systems that simplify the processing ... Library:
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Title: Възстановяващи се напрежения на прекъсвачи 35kV при комутиране на шунтови реактори Author: Колев, Валентин Генов; Kolev, Valentin Genov Date: 1995 Abstract: Calculation of recovery voltage is made in correction with posibility of adding of a vacuum surge breacker type VCI 1-36/25/1250 of company Holec. A tree phase model was investigated using the method of state varyables in the process of switching off of a shunt reactor. A special software is designed for calqulating the transient processes ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Статистически характеристики на хармоничните съставки на тока на газоразрядни светлинни източници Author: Сидеров, Сидер Тонев; Диканаров, Георги Иванов; Dikanarov, Georgi Ivanov; Siderov, Sider Tonev Date: 1995 Abstract: The report treats the results of the experimental research on the harmonic components of the electric current of the different types discharge light sources, applied in different circuits. The probability-statistical components of the current are defined. The obtained results alow to carry out an analysis of the nonsinuous regimes of the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Изследване на пулсациите на потока на източниците на светлина Author: Диканаров, Георги Иванов; Пачаманов, Ангел Саракинов; Dikanarov, Georgi Ivanov; Pachamanov, Angel Sirakov Date: 1995 Abstract: The report treats the results of the research on the pulsations of the radiant flux of a broad scale of lighting sources and the most widely distributed nowadays huninaries with fluorescent lamps, produced in the country or imported by leading companies. The experimental circuits for carrying out the measurements, the methods of research ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Анализ на честотната зависимост на tgδ за оценка на стареенето на кабелна изолация Author: Тодорова, Антоанета Константинова; Дюстабанов, Георги Иванов; Todorova, Antoaneta Konstantinova; Dustabanov, Georgi Ivanov Date: 1995 Abstract: A method for valuation of the change in the state of compounded insulation in the process of its ageing is proposed. The ageing degree is observed by periodically measuring of frequency dependancy of tgδ and by calculating the quantity... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Изследване на електромагнитното поле в двуслойни плоски среди, възбудено от стрикциомагнитен преобразувател със сложна форма Author: Гунински, Стефчо Георгиев; Guninski, Stefcho Georgiev; Цанов, Димчо Димитров; Tsanov, Dimcho Dimitrov Date: 1995 Abstract: In this paper the magnetic vector-potential is analitically determinated and thus the magnetic field in the system "magnetoelastic transducer with complex shape (with jive poles)-ferromagnetic conductive two-layer plane object" is calculated. The obtained results allow its to make various optimization investigations of magnetoelastic, ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Изчислителен метод за определяне на параметрите на асинхронна машина Author: Илиев, Тотьо Илиев; Iliev, Totyo Iliev Date: 1995 Abstract: The paper offers a new method of approach for determination of asynchronous electric motors There are offered relationships and approximative expressions, determining parameters depending on power of the electric motor, which may be used or projecting electric motors of definite class. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Механични характеристики на мощни асинхронни двигатели Author: Тодоров, Георти Тодоров; Todorov, Georgi Todorov Date: 1995 Abstract: The rotor winding parameter's variation is described taking into account the skin effect and unsteady heating in height of the rotor bar at starting. Its effect on the tomtit,- slip characteristics is analysed at a different duration of starting. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Определяне на средногодишния разход на електроенергия на подемно-транспортни механизми с циклично действие Author: Йорданов, Светослав; Yordanov, Svetoslav; Кутрянски, Крум; Kutryanski, Krum Date: 1995 Abstract: The application of technical-economical criterion for choose and selling-up of electric drive system needs finding of average annual energy consumption for compared variants and parameters of systems. This problem is very difficult for cyclic duty mechanisms because of the necessity of accounting the laws of probability distribution of ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Изчисляване на механичните характеристики на асинхронен двигател в режим на кондензаторно спиране Author: Райнов, Румен Иванов; Raynov, Rumen Ivanov Date: 1995 Abstract: A method for computing of mechanical characteristics of an asynchronous motor operating of condenser stoppage mode is proposed. The essential influence of the magnetization curve over the form of mechanical characteristic by is shown. The method allows to examine the particular parts of the mechanical characteristics at the beginning and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Определяне на номиналните параметри на асинхронни двигатели по табелните им данни Author: Йорданов, Светослав; Райнов, Румен Date: 1995 Abstract: A method for determination of the equivalent circuit parameters of induction motors, based on the name plates data and using of the statistic relations is propoused. Evaluations of the maximal and the average errors are represented. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Противобоксуващи схеми за токоизправителни електрически транспортни средства Author: Българанов, Любомир Борисов; Balgaranov, Lyubomir Borisov Date: 1995 Abstract: The realised adhesion coefficient is influensed very much by the way of collecting the tractive motors, by the way of their control as well as by the existence and the character of the protection against sliping.In this article are suggested and analised some schemes against sliping for alternative current rolling stock. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Към определянето на вероятността за безотказна работа в заден интервал от време в условията на стационарен процес с моментално възстановяване Author: Цочев, Христо Цветанов; Tschev, Hristo Tsvetanov Date: 1995 Abstract: The determination of the steady-state probability R+(h) of no failure on the interval (t, t +11) in conditions of renewal process is considered as a problem of designing. A formula for calculation the probability R+(h) in a case of simplified presentation the relationship between the failure rate X and time t is proposed. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Експериментално определяне на динамичните характеристики на електромеханични измервателни уреди Author: Маджарова, Мария Димитрова; Madjarova, Marija Dimitrova Date: 1995 Abstract: The amplitude — frequency characteristic of a permanent-magnet moving - coil (PrifIliC) instrument has been experimentally obtained. The prelimenary frequency response characteristic has been determined through the approximation of the logarithmic amplitude —frequency curve. The both performances: Theoretical and experimental, has been ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Върху инвариантността на определителните изрази при различните състояния на променливотоковите измервателни мостове Author: Ставракев, Желязко Анастасов; Иванов, Иван Николаев; Туренков, Васил Николаев; Stavrakev, Zhelyazko Anastasov; Ivanov, Ivan Nikolaev; Turenkov, Vasil Nikolaev Date: 1995 Abstract: In the article, it is shown, that for every equilibrated or quasiequilibrated state for a given type of four branches bridge, the determinated expression of the unknown parameter, which can be measured, is the same. It is shown as well, that if one of quasiequili-brated states is possible (amplitude, zero-phase, square phase) the same ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Теорема за съществуването на ефективен коефициент на усилване на веригата на правото предаване Author: Станчев, Иван Борисов; Stanchev, Ivan Borisov Date: 1995 Abstract: A theorem, according to which the three, transmission circuit of each amplifier with negative feedback is characterized by a coefficient of transmission, named efficacious gain. This coefficient according to the theorem is deffinited as multiplication of the gain's own of the electronic amplifiers and the coefficient of transmission of the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Възможности за намаляване на грешките от входните токове на операционните измервателни усилватели Author: Станчев, Иван Борисов; Куртев, Иван Александров; Иванов, Иван Николаев; Stanchev, Ivan Alexandrov; Kurtev, Ivan Alexandrov; Ivanov, Ivan Nikolaev Date: 1995 Abstract: Possibilities to decrease the input current errors at some circuits of measurement amplifiers are examined. First a method is suggested for compensation of the voltage drop, which appears in math-wig precise tension divider placed at the input of the amplifier. At the second for-the inverting amplifier with variable gain an .optimal value ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Transient processes in three-phase three-winding autotransformers after switching on at open-circuit conditions Author: Tagarov, Kiril D.; Тагаров, Кирил Д. Date: 1995 Abstract: One of the most difficult problems by the computation of electromagnetic tran-sients in power autotransformers is, that in most cases some of the necessary data for the transformer paranzetres are not available. In this paper is proposed a method to complete those data that are needed for the computation of electromagnetic transients but ... Library:
TECHNICAL UNIVERSITY - SOFIA