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EN
In the paper friction phenomena test stand concept and technical solution is presented. Authors subjected on friction phenomena, based on motorbike disc brake assembly, prepared its original concept of friction and motorbike brakes research. In the publication, a detailed description of construction and system control is contained. Designed motorbike disc brake assembly friction test stand can offer few research programs. It is also possible to introduce own research program based on a real motorbike driving in different traffic conditions. Preliminary motorbike road test results are presented. A motorbike drive possesses characteristics of acceleration, speed, brake road distance, power of acceleration and deceleration. The initial investigation described in this paper can be a good introduction for a more advanced research where variable coefficient of friction and other friction phenomena values can be estimated. On the basis of presented methods, this can also develop an investigation of energy dissipation values. Energy parts designated in brake and friction process can be applied to mathematical description of friction phenomena and mechanical material destruction.
PL
Przedstawiono analizę zjawisk dynamicznych, które mogą wystąpić podczas pracy synchronicznej silnika indukcyjnego pierścieniowego. Zjawiska te spowodowane są typowymi stanami zakłóceniowymi jakie mogą wystąpić w układzie zasilania silnika. Do nich należy zaliczyć: obniżenie napięcia spowodowane procesami technologicznymi lub rozruchem silników dużej mocy, niesymetryczne obniżenie napięć fazowych spowodowane stanami awaryjnymi sieci, chwilowy zanik napięcia zasilania itp. Zjawiska te mogą wystąpić podczas pracy silnika, dlatego istotne jest poznanie ich wpływu na przebieg i wartość momentów dynamicznych, prądów i prędkości silnika pierścieniowego pracującego w stanie synchronicznym. W artykule przedstawiono wyniki badań symulacyjnych wybranych zakłóceń oraz sformułowano wnioski i zalecenia eksploatacyjne dla tego typu napędów.
EN
The paper presents the analysis of dynamic phenomena that may occur during synchronous operation of slip-ring induction motors. These phenomena are caused by the typical conditions that may occur in the motor. To them include: voltage reduction caused by technological processes or start high power motors, unbalanced phase voltages decrease caused by emergency power system conditions, momentary lack of supply voltages, etc. These phenomena may occur under normal operating conditions is therefore important to assess their influence on the course and value of dynamic torques, currents and rotational speed of slip-ring induction motor operating in the synchronous state. The article presents the results of simulations of selected interference and formulated conclusions and recommendations for this type of drive.
PL
W artykule przedstawiono problemy związane z procesem synchronizacji, utraty synchronizacji oraz ponownej synchronizacji typowych silników indukcyjnych pierścieniowych pracujących w napędach różnego typu. Przedstawiono metody pozwalające łagodzić niekorzystne stany dynamiczne podczas utraty synchronizacji wywołanej przez chwilowe przeciążenie maszyny lub zmniejszenie wartości napięć zasilających stojan. Badania obliczeniowe wykonano wykorzystując opracowany polowo-obwodowy model numeryczny dla wybranego typu silnika pierścieniowego dużej mocy.
EN
The paper presents the problems connected with the process of synchronization, loss of synchronization and resynchronization typical slip-ring induction motors, working in different types of drives. The paper also presents the methods to attenuate the dynamic waveforms during the synchronization loss caused by momentary overload the machine or reduce the value of the stator voltages. The computational studies were performer using a specially developed field-circuit numerical model for the selected type of high-power slip-ring induction motors.
EN
The work presents construction and realization technology of three types of rotors for use in low power permanent magnet synchronous motor, designed to synchronous starting. The results of synchronous starting calculations for a selected model of the surface mounted permanent magnet synchronous motor (SMPMSM) are presented. The influence of initial value of the stator voltage (f=0Hz) and initial rotor position on waveforms of the basic quantities during starting has been investigated. The calculations were performer using a specially developed field-circuit models of the motor. The calculation results are presented in the form of diagrams.
PL
Przedstawiono problemy związane z procesem synchronizacji, utraty synchronizacji oraz resynchronizacji typowych silników indukcyjnych pierścieniowych pracujących w napędach różnego typu. W artykule przedstawiono propozycję rozwiązania problemu łagodnej synchronizacji tych silników po dokonaniu rozruchu asynchronicznego oraz wyniki badań symulacyjnych wskazujących na celowość stosowania tego rozwiązania w wielu napędach przemysłowych. Zaproponowano również metodę pozwalającą łagodzić niekorzystne stany dynamiczne podczas utraty synchronizacji wywołanej przez chwilowe przeciążenie maszyny. Obliczenia wykonano wykorzystując opracowany polowoobwodowy model obliczeniowy dla wybranego typu silnika pierścieniowego dużej mocy.
EN
The paper presents problems connected with processes of synchronization, loss synchronism and restoration synchronism for typical slip-ring induction motors applied in various industrial drive systems. The calculations were performed using a specially developed field-circuit calculation model for a selected model of the large power slip-ring induction motor. The calculation results are presented as diagrams over time.
EN
The problems connected with the synchronization process of typical slip-ring induction motors applied in various industrial drive systems. In comparison to synchronized induction motors (SAS) which have constructions designed for synchronization after starting the typical slip-ring induction motors are not suited for synchronization process. The main reason is that the control systems perform the synchronization process in the moment which is not optimal for that process. The article presents the solutions of this problem. The study results show that the presented method can be applied in many industrial drive systems.
PL
W artykule przedstawiono wyniki badań zmian podstawowych parametrów blach elektrotechnicznych stosowanych na magnetowody maszyn indukcyjnych, które mogą być wykorzystane do pracy w warunkach zbliżonych do kriogenicznych. Przeprowadzono także badania symulacyjne i zamieszczono uzyskane wyniki wpływu wyboru kształtu żłobka wirnika oraz materiałów z których mogą być wykonane pręty i pierścienie zwierające na podstawowe parametry silnika indukcyjnego klatkowego. Wykazano, że dobierając odpowiedni kształt pręta wirnika oraz materiał, z którego wykonana jest klatka, można wpływać na wartość i przebieg istotnych parametrów silnika. Badania symulacyjne wykonano dla silnika o mocy około 1 MW, 6 kV przeznaczonego do napędu pompy ciekłego gazu LNG wykorzystując w trym celu program Flux 2 D. Oprócz badania wpływu kształtu i materiału wirnika na parametry eksploatacyjne przeprowadzono także badania symulacyjne wpływu zamknięcia żłobków stojana klinami magnetycznymi na zmiany parametrów silnika. Rozwiązanie to posiada zarówno zalety jak i wady, które przedstawiono w artykule.
EN
In the paper the results of studies oriented info basic parameters of electrotechnical sheets are presented. The sheets are appropriated for magnetic circuits of induction machines working in very low temperatures. The simulation studies of the influence of the rotor slot shape and of the material kind of rods and end-rings on the electromagnetic parameters of squirrel-cage induction motor are performed. The simulation studies are realized with using Flux software for the 1 MW, 6 kV induction motor, designed for the drive system of liquid gas pump. It has been proved that through the proper shape design of rotor rods and the proper choice of squirrel-cage material kind it is possible to have an effect on the basic electromagnetic parameters of the motor.
EN
The paper presents the influence of slot geometry and resistivity of squirrel cage materials on characteristics high power motor’s. Changes of electromagnetic torque run and of electrical current run as they appear in the motor with given solutions were analyzed and compared. In the paper, works concern testing and selection of generator sheets for realization of motor working in liquid natural gasses with temperature -161°C are presented. Apart from this, the results of tests conducted in liquid nitrogen environment and room temperature are included. To choose the optimal kind and thickness of electrical sheet, the behavior of electrical sheets with different thickness and kind of insulation were examined. The magnetic parameters of the tested electrical sheets, such as: magnetic induction, total energy loss with division on hysteresis and eddy current loss were determined. Simulational analyses were conducted using circuit-field method.
9
Content available remote Modyfikacja układu łagodnej synchronizacji silników synchronicznych dużej mocy
PL
W pracy przedstawiono propozycje modernizacji rzeczywistego układu łagodnej synchronizacji silników synchronicznych dużej mocy. Modyfikacja zapewnia możliwość wyboru chwili załączenia napięcia wzbudzenia z uwzględnieniem zmiennych warunków pracy układu napędowego. W celu sprawdzenia przyjętej metody sterowania na przebieg procesu synchronizacji wykonano odpowiednie obliczenia wykorzystując opracowany obwodowy model silnika synchronicznego dużej mocy typu GAe 1716t. Wyniki obliczeń zamieszczono w postaci wykresów czasowych.
EN
The work presents proposal modernization of real soft-synchronization system for high power synchronous motors. The modification allows to select of the moment of the beginning synchronization process with consider change in work's parameters of the drive. The influence of the modernization on synchronization process has been investigated. The calculations were based on the examined circuit model for the high power motor, type GAe 1716t. The results of calculations were presented as time curves of state variables.
PL
W artykule przedstawiono możliwości wykorzystania silników reluktancyjnych o rozruchu asynchronicznym do pracy w ciekłych gazach dielektrycznych. W szczególności dotyczy to urządzeń pracujących w ciekłym gazie naturalnym LNG o temperaturze -161 °C. Podano wyniki badań materiałów konduktywnych i magnetycznych w niskiej temperaturze. Uzyskane wyniki badań umożliwiły wykonanie obliczeń symulacyjnych podstawowych zmian parametrów eksploatacyjnych silnika reluktancyjnego małej mocy po schłodzeniu go do temperatury ciekłego gazu. Uzyskane wyniki porównano z wynikami badań eksperymentalnych typowego silnika indukcyjnego klatkowego o analogicznej mocy.
EN
The paper presents the possibility of application of reluctance motor with asynchronous starting which was designed for work in dielectric liquid gases. Particularly it concerns the devices working in Iiquid natural gas (LNG) in temperature of-161 °C. The results of conductive and magnetic materials in cryogenic temperatures were presented. The obtained test results were applied to the computer simulation of changes of basic operational parameters of Iow-power motor after cooling up to liquid gas temperature. The simulations results were compared with operational parameters of typical induction squirrel-cage motor with analogical power.
EN
The paper presents test results concerning the influence of the kind of frequency converter used on static and dynamic parameters of a drive with reluctance motor at asynchronous startup. Vector- and scalar controlled converters most widely applied in the industry underwent tests. It was found that there exists the dependence between the kind of converter employed and the parameters of the drive with this type of reluctance motor. The frequency of input voltage modulation also influences the dynamic parameters. Basing on the study carried out, it was demonstrated that SVL vector controlled converters should be mainly used for the powering of such kind of motors. Vector controlled frequency converters of higher quality may introduce engine trouble, as far as the work of drives with such motors is concerned.
12
Content available remote Zagadnienia sterowania napędów przemysłowych
PL
W artykule przedstawiono informacje dotyczące prowadzonych prac badawczo-wdrożeniowych z zakresu sterowania przemysłowych układów napędowych. Prowadzone prace dotyczyły bardzo różnorodnych zagadnień obejmujących zarówno problematykę przemysłu ciężkiego, maszynowego, kopalń i przemysłu lekkiego. Pomimo różnorodności przeznaczenia i wymagań stawianych realizowanym pracom można wyróżnić pewną wspólną ich cechę, którą był energoelektroniczny system sterowania silników napędowych. Przedstawiono krótki przegląd prac realizowanych w latach 1975-2004.
EN
The paper presents information concerning research and development works conducted in the field of power transmission systems control. Works conducted were concentrated on various issues encompassing both the issues of heavy and light industry, as well as those of engineering and mining industry. Despite the differences as far as the designation and requirements imposed on the realized works, a certain common feature can be distinguished which is power electronical motor drives control system. A short review of works realized between 1975 and 2004 is included in the paper.
PL
W artykule przedstawiono wyniki badań silnika reluktancyjnego z rozruchem asynchronicznyrn w dwóch wersjach konstrukcyjnych: bez dowzbudzenia od magnesów trwałych i z dowzbudzeniem od magnesów trwałych. Przeprowadzone badania miały na celu zbadanie możliwości zasilania tych silników z przemienników częstotliwości stosowanych do zasilania silników indukcyjnych klatkowych. Wykorzystano do badań przemienniki częstotliwości o sterowaniu skalarnym i wektorowym: typu SLV i VVC plus , najbardziej popularne w przemyśle. Przedstawiono wyniki badań statycznych i dynamicznych napędu z silnikami reluktancyjnymi o dwóch konstrukcjach wirnika oraz podano wnioski wynikające z badań co do możliwości wykorzystania różnych typów przemienników do zasilania tego typu silników.
EN
The paper presents test results of reluctance motor with asynchronous startup in two of its construction versions: with no permanent magnet excitation and with permanent magnet excitation. Conducted tests were aimed at verification of such motors' powering from frequency converters used for powering of squirrel cage induction motors. The most popular in industry, scale- and vector controlled frequency converters of the type SLV and VVC plus were used for the tests. The paper includes test results from static and dynamic tests of a drive with reluctance motors of two rotor constructions. Furthermore, it presents the conclusions drawn from the tests, as far as the possibility of using various kinds of converters for powering of such motors is concerned.
14
Content available remote Częstotliwościowe sterowanie napędów pośrednich przenośników taśmowych
EN
Indirect drive in long belt conveyors can lessen the stresses in the belt and in the load bearing structure of the conveyor because of the distribution of the belt's pulling force into several components of force. The indirect drives without pouring point are interesting solutions both from the technical, and the economical points of view. Most frequently used solution is an auxiliary conveyor which drives the runners of the main conveyor. The problem in manufacturing this sort of drives is both the variability of thermal compression between the belt and runners in belt load function, and the necessity to adjust the driving velocity of the auxiliary drive's motor to the current parameters of the main belt's load. All these requirements cause the driving motors of the auxiliary drive to be powered from the frequency converter Typical methods of frequency changer control do not always provide satisfactory results in the difficult working conditions of the auxiliary drives, the use of positioning system of induction motors was suggested. Conducted laboratory tests of the drives showed the advisability of usage of machine tool motor for the realization of indirect drive for belt conveyors.
EN
Selected problems relating to positioning by means of typical squirrel-cage induction motors supplied from a frequency converter equipped with a special positioning controller are considered. The dynamics of the drive during positioning, the selection of PID controller parameter values and its effect on the accuracy of positioning and speed mapping are discussed. The results of bench tests of the power transmission system for different controller parameter, load torque and M.I. values are presented. The measurements were performed for different prescribed rates of increment and decrement in drive parameter (ramp) values and under different frequency converter current constraints whereby the requirements which the motor and the supply converter in drives of this type must meet could be determined.
16
Content available remote Przemienniki częstotliwości w wielosilnikowych napędach współbieżnych
EN
This paper presents a multimotor concurrent drive whose slave drives are induction squirrel-cage motors supplied from frequency converters equipped with control systems for synchronizing the drives. The control system of the multimotor concurrent drive, the results of tests carried out on the drive and the problems encountered in its realization are discussed. The concurrent operation of drives in multimotor systems and the equalization of the loads carried by the drives still pose a problem. The proper concurrent operation of the drives is crucial for the quality of the operation of the whole system, the proper loading of the individual motors and for reducing the losses associated with the equalization of the loads. If the problems with proper and energy-saving equalization of loads and detracing of the set speed are solved, this will facilitate, among others, the construction of long belt conveyors equipped with intermediate drives. In many cases, the use of frequency-controlled drives as the slaves can be a satisfactory solution. A frequency-controlled drive or a conventional induction drive (e.g. with a soft-start starter) can be the master drive. A crucial problem in the realization of detracing drives is the proper choice of both the control system structure and the settings of the frequency converters' controllers. Conventional and digital PID controllers and equalizers preventing any velocity or acceleration errors are used in the control systems of frequency-controlled concurrent drives. A suitable control structure and proper controller settings ensure that the drive performs well in both static and dynamic states. The results of bench tests of a power transmission system in which the slave drive adjusts its speed to changes in the speed of the master drive, whereby a concurrent drive is formed, are presented. The influence of control system structure and controller settings on the quality of the realization of the set speed by the slave drive is analysed. Conclusions and recommendations concerning the realization of this type of drives are given. The function which pre-emptive velocity and acceleration equalizers perform in the considered drives is highlighted and the principles of programming the equalizers are explained.
EN
A design of a mine fan whose supply system includes a frequency converter operating at a constant frequency of 16.6 Hz and the results of tests carried out on the fan are presented. The frequency converter is supplied from a separating transformer and it is used during mining downtimes or in periods of lower demand for air in the ventilated area. Owing to its characteristic the fan offers considerable savings in electricity. An inexpensive, simple but robust frequency converter can be used to provide the required low frequency. This solution can be used in all cases where no continuous control of capacity is needed and where the use of a conventional frequency converter would be inadvisable for economic and technical reasons. In an alternative solution, a two-speed motor with a variable speed difference (e.g. 3 : 1) is used. But this solution is inferior since a two-(or more) speed motor is needed to adjust the low speed to the individual requirements of the quite complex speed switching system and the drive's efficiency and power factor cos phi without individual compensation are rather low. The employed compensating capacitors may cause resonances in the mains, the more so that static converters are more and more widely used. The performance of the fan's drive when a two-speed motor with a fractional speed ratio is used and that of the drive with an additional inverter supplying a conventional motor and a motor with a winding consisting of two parallel conductors are compared. The proposed solution is shown to be both economically and technically viable, introduces little interference into the mains and the motor, can be used in the drives of pumps and fans operating in different industries and the investment quickly pays off.
EN
The paper presents the frequency controlled drive system with squirrel-cage induction motor, PWM voltage source inverter and power feedback unit used for energy regeneration during regenerative braking operation of induction motor. By using power feedback unit the braking energy which otherwise is most often wasted in resistors is supplied to the three phase AC grid. The basic circuits of power converter system with application of power feedback unit are presented. The analytical-economical criterion for applying power feedback unit is discussed. The equations used in economical analysis and for selection the proper configuration of the drive system are presented. The results of experimental studies of the drive system with power feedback unit are presented and discussed. The laboratory equipment consisted of induction motor coupled with direct current motor. During the motor operation the induction motor was fed from a PWM voltage source inverter. As an inverter the industrial frequency converter produced by Danfoss was used. During the braking operation the dc motor was used as a drive motor and the induction motor worked in the state of regenerative operation. During that operation the power feedback was used in the drive system for energy regeneration. The industrial power feedback unit produced by REVCON was used in the drive system. The power feedback unit was switched on by the control circuit. The other equipment used in measurements was described.
EN
A two - speed synchronous motor of a salient - pole rotor and with windings of changeable pole - pairs number is presented. The GAe 1510/12p motor of 1250 kW is equiped with switchable windings in the stator as well as in the rotor. The motor characteristics make it suitable for drives of fan - type machines. Application of this kind of motors as drives for ventilators in underground mines permits the two - step control of the ventilator output which results in considerable energy savings. Curves of ram pressure delta(p), power N and efficiency eta as a function of flow V at rotational speeds n = 600 and 500 rpm show this effect (fig. 3). The capital cost of such a speed control method is much lower than if an electronic converter were applied (table 2). There is possibilty of reactive power compensation at both motor speeds. "V" curves measured at open guide apparatus and two different rotational speeds are presented in fig. 4. A proper choice of rotor winding improves the motor starting current and dynamic torque characteristics. Some results of testing of GAe 1510/12p motor of 1250 kW, obtained during its normal working conditions are given in the paper. Transients of starting currents at n = 500 obr/min and n = 600 obr/min show figs. 5 and 6. The stator currents and supply voltage wave at n = 500 obr/min are given in figs. 7 and 8.
PL
Przedstawiono opis przekształtnikowego układu napędowego złożonego z silnika indukcyjnego klatkowego, falownika napięcia MSI oraz urządzenia energoelektronicznego do zwrotu energii elektrycznej z obwodu pośredniczącego falownika do trójfazowej sieci zasilającej. Omówiono ekonomiczne aspekty wyboru układu hamowania i celowości stosowania urządzenia do zwrotu energii podczas stanów hamowania elektrycznego silnika indukcyjnego. Przedstawiono wyniki badań laboratoryjnych przekształtnikowego układu napędowego, sterowanego przez falownik napięcia MSI dla stanów pracy silnikowej i hamowania odzyskowego silnika indukcyjnego.
EN
The drive system consisting of a squirrel-cage induction motor, a PWM voltage source inverter and a power feedback unit used for recuperation of braking energy from a dc circuit to the three-phase mains is described. The economical criterion for selecting the braking scheme and application of a power feedback unit are discussed. The results of experimental investigations of the motor and regenerative braking operations of the drive system with inverter-fed induction motor and power feedback unit are presented.
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