The article presents the possibility to diagnose a machine – physical object – in particular diesel engine. Studies were organized to demonstrate the possibility to use LDV (Laser Doppler Vibrometry) in the fundamental (diagnostic) studies. The object tested is a common model of modern diesel engine, frequently used in currently available vehicles. This paper describes the results of researches performed based on the displacement and the velocity, which indicates usefulness of each of these variables. In addition, the article presents older type of vibration detection system uses in vehicles (based on accelerometers) and conditioning path of the received vibroacoustic signal to become complete and fully useful diagnostic information.
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Turbogeneratory są i w najbliższym czasie pozostaną podstawowym źródłem energii elektrycznej. Współcześnie produkowane są stojany o mocy powyżej 2 GW, w projektowaniu zaś są coraz to większe jednostki. Przy tak wielkiej koncentracji mocy szczególnego znaczenia nabiera niezawodność i trwałość maszyn. Badania teoretyczne, laboratoryjne, jak i doświadczalne analizy zjawisk w układach elektroizolacyjnych maszyn elektrycznych wysokiego napięcia zmierzają do określenia wskaźników diagnostycznych opisujących stopień zużycia izolacji. Działania te stanowią podstawowe cele prac w dziedzinie diagnostyki wysokonapięciowej. Układ izolacyjny jest to struktura przestrzennie złożona z materiałów nośnych, izolacyjnych i przewodzących, zapewniających odpowiednią wytrzymałość elektryczną i funkcjonalność urządzenia. Izolacja uzwojeń w maszynach elektrycznych – zwana często „złem koniecznym” – jest elementem wymagającym zwiększenia gabarytów maszyny lub zmniejszenia jej mocy przy zachowaniu dotychczasowych wymiarów.
EN
Paper contain laboratory study of partial discharge (PD) measurement on turbo-generator bars with a voids. Partial discharge patterns and PD interpretation were showed.
W pracy przedstawiono metody i sposoby prowadzenia diagnostyki maszyn elektrycznych podczas ich kolejnych faz życia. W dalszej części podjęto próbę dokonania oceny, biorąc pod uwagę rodzaje występujących uszkodzeń oraz przyczyny powstania awarii napędów przemysłowych.
EN
This paper presents the methods of diagnostics of electrical machines during the next phases of life. Later in an attempt to assess the industrial drive, taking into account the types of damage occurring and the reasons for the failure.
The paper aims at showing the possibilities for effective application of laser diagnostics vibrometers operational drives of electrical machines. To measure vibrations Laser Vibrometer VH-1000 is one of the few such facilities in Poland and brings a new quality and performance in vibration measurements and diagnostics of machines. Vibrometer laser provides a measurement of non-contact vibration, thus eliminating interference caused by ground sensors and high temperature measuring point. In addition, the measurement can be performed from a distance. As a vibration sensor can operate with any vibration analyzer for direct entry into the recording and analysis of the measured signal. There are a wide frequency band, allowing for vibration analysis of frequencies near zero, which gives the possibility of diagnosis for low rotor speed. Non-contact vibration measurement allows a direct measurement of shaft vibration machines, which brings new quality into the possibilities of their diagnosis. The authors describe the use of laser vibrometer in the diagnosis of low speed engines. We apply laser vibrometer diagnostics engines using vibration shaft, face the stator windings. The authors show the possibility of using laser measurement and vibration analysis of high voltage transformer and the resonant frequencies of electrical equipment. ased on the examples of laser vibrometers diagnostics of machines you can say that is a new and significantly expanding opportunities for diagnostic tool technical evaluation of electrical equipment.
FFT analysis of one of the stator currents has become a standard procedure for diagnosing the state of an induction machine. In this procedure the harmonics are all as if positive. However, if the stator currents are aggregated to a space vector, a direction of rotation of complex harmonics is determinable. The sign of a harmonic conveys additional information, important for diagnostic purposses. The paper presents analyses of calculated currents, based on an FFT algorithm for two currents. As, typically, a machine is fed through three cables, two currents are sufficient to establish a space vector of stator currents. The space vector is a complex quantity which can be put into an FFT analysis. A developed software is fitted with graphical interface. Unlike traditional display, separate amplitudes of harmonics are displayed above and below a horizontal frequency axis. The harmonics rotating in positive direction are displayed above, and the others below the frequency axis. The software automatically indicates zones where the slot harmonics are expected. The algorithm for this is based on a specific harmonic balance model. Based on the frequency of a slot harmonic, the rotor speed is determined. Preliminary analyses are uncluded.
This short document describes represents question about maintenance and diagnostic of electric drive system . Preventive working are important element in work of plant. Qualification of technical state of machines lies out the directions of repairs and observation Industrial plant which they work in continuous system they require different way of repairs. Author represents his working for assurance of correct work of devices. The task of maintenance was introduced for on-line and off-line.
Current-based diagnostics of electric motors is most common in the industry. Almost all basic defects of the motor are "reflected" in the current of the stator in the induction motor. Using measurements and analysis of a current signal, we can detects the following, among others, in the motor: cage damages; gap asymmetry; the lack of centricity in the setting of the motor in respect of the driving machine; unbalance of the rotor; bearing damages; partial discharges in the insulation. In the article, the authors presented the issue of measurement and analysis of a current signal; they also analysed the use of individual measuring detectors. The article shows possibilities of using Rogowski coils for utilisations diagnostics of squirrel-cage induction motors. It presents possibilities of application for: detection of non-alignment in the drive; cage damages; and air-gap asymmetry.
The paper presents application of the radial neural network for detection of faults in induction motor stator winding. The decision of stator winding condition has been taken using the artificial neural network with radial basis function based on axial flux. The axial flux has been measured for different configuration of stator winding. It can be concluded that the axial flux can be used in detection of faults in induction motor stator winding.
The article is a summary of dozen-year experience of workers researching at Institute of Electrical Machines of Warsaw University of Technology and at Institute of Power Engineering. The professional experience has been related to technical diagnosis of engines, generators and energetic transformers. The authors form postulates to constructors and electrical machine creators. The aim of these statements is to prepare the devices suitably to be able to conduct efficient diagnostics offline as well as online. Even though the diagnostics has been taken into consideration what has succeeded in an improvement , services of motion maintenance and technical supervision have still been encountering numerous problems connected with receiving signals needed in the process of creating the right diagnosis. Crucial difficulties appear every time when the examined machine junctions are tried to be reached or appropriate sensors are installed, etc. The analysis has been done with the connection of types of signals listed below: vibration, electromagnetic, thermal.
This paper deals with 3D scanning in power electrical engineering. Specifically, using a scanner company Z800 Z-Corporation. This scanner was used to diagnose the structure of the electric machine coil. After taking all necessary steps to create 3D models from scanned data the model was obtained. This model was compared with the model that was created in one of modern CAD systems. This model made for the primary model for the production of measured coil. The variations in the construction of a coil were identified. Subsequent analysis identified the causes of changes in dimensions.
This short document describes represents question about maintenance and diagnostic of electric drive system . Industrial plant which they work in continuous system they require different way of repairs. Preventive working are important element in work of plant. Qualification of technical state of machines lies out the directions of repairs and observation. Every element of driving system should possess supervisory apparatus. Author represents his working for assurance of correct work of devices. The task of maintenance was introduced for on-line and off- line.
Fault diagnosis is currently a target of wide research activities. There is large number of diagnostic methods based on various source of diagnostic signal, signal processing and data evaluation approach. Stator current is traditional diagnostic signal for fault detection of induction machines. Monitoring of this signal is mainly effective in case of diagnosis of broken rotor bars and rings. However, analysis of external magnetic field appears to be more powerful in case of rotor eccentricity detection. The measurement system based on LabVIEW platform is now presented and it includes both stator current and external magnetic field analysis.
The paper presents a concept of realization of an expert system for monitoring and diagnostics of electric direct current commutator machines. A perceptron regulator of the current of commutation poles is sometimes incapable of eliminating or reducing the sparking of brushes. This may be due to mechanical or other additional factors, which were not taken into consideration in the process of instruction of the artificial neural network ANN described in the previous paper. That is why the application of a damage detector will allow to control states of emergency or machine failures and to inform the system operator or shut down.
Celem artykułu jest przedstawienie możliwości zastosowania automatycznego systemu dialogowego w diagnostyce maszyn elektrycznych [5], [6], [7], [8]. Automatyczny system dialogowy pozwala nawiązać kontakt pomiędzy użytkownikiem i komputerem [9]. Ten system dialogowy analizuje zdania użytkownika i generuje swoje zdania w języku naturalnym. Język naturalny jest zdefiniowany za pomocą metod formalnych, w tym gramatyk i automatów. W artykule przedstawiono wyniki badań.
EN
The paper aims at presentation of potential of use of an automatic dialogue system designed for diagnostics of electric machines [5], [6], [7], [8]. The automatic dialogue system allows a user to establish a contact with a computer [9]. The dialogue system analyses the user's tasks and generates its tasks in a human language. The human (natural) language is defined by formal methods including a grammar and automatic mechanisms. The results of research have been presented as well.
Possibilities of inverter-fed motor damages modeling may radically simplify building of on-line working diagnostic algorithms. Choice of those signals and coefficients, on which real-time working algorithms could estimate motor drive's technical state is an important problem. The way of numerical modeling, based on the original program solution using object C++ programming techniques is presented in the paper. Results of numerical modeling of field-oriented controlled motor drive, including motor damages such as rotor bar braking or rotor eccentricity are included. Effects indicate on the possibility of use of moving RMS current value and flux error signal-based estimation coefficients for on-line diagnostics of a motor drive.
The paper presents a concept of realization of an expert system for monitoring and diagnostics of electric direct current commutator machines. A perceptron regulator of the current of commutation poles is sometimes incapable of eliminating or reducing the sparking of brushes. This may be due to mechanical or other additional factors, which were not taken into consideration in the process of instruction of the artificial neural network ANN described in the previous paper. That is why the application of a damage detector will allow to control states of emergency or machine failures and to inform the system operator or shut down.
It is possible to execute diagnostics of induction motor on the basis of the moving rms stator current signal in cases of non-sinusoidal supplying. The results of using of this signal in diagnostics of induction motor supplied by non-symmetrical, sinusoidal 3-phase voltage have been presented in this paper. It has been used the moving rpm for analysis different damages of induction motor and perform review of results to use this signal in diagnostics. Dynamical model of this machine calculates harmonics of stator, rotor and stator-rotor inductances accounting for only global saturation of the air-gap region. The model considered various rotational speeds of the rotor.
The diagnostics of insulating system of electric machines under pulse stress is at the present one of the most focused fields. The converters produce repetitive pulses with the high level of voltage rise fronts (slew rates). Rise fronts attain values of up to the tens of kilovolts per microsecond and voltage pulse repetition frequency up to some tens of kilohertz. However, this technology is an advantage for a drive control; the voltage waveforms generated by power frequency converters may significantly affect the reliability of the electric motor insulation systems. To improve understanding of the processes in the electrical insulation materials during the pulse voltage aging, it is necessary to monitor values of the electric parameters within a pulse stress aging process. For the studying of the main-wall insulation material pulse voltage aging processes there were chosen these electrical parameters: the dissipation factor, capacity, absorption and resorption currents, corona inception voltage (CIV) and partial discharges (PD) activity level. These parameters are easily detectable and their development characteristics are very well known in the terms of sinusoidal voltage aging process. This paper presents experimentally measured data of the observed electric parameters during the pulse and sinus voltage aging. The difference between the sinusoidal voltage aging and pulse voltage aging time dependencies is shown as well observable in this paper as well.
PL
Diagnostyka układu izolacji maszyn elektrycznych metodą impulsową nabiera coraz większego znaczenia. Przemienniki wytwarzają powtarzające się impulsy o wielkiej stromości narastania napięcia osiągające wartość kilkudziesięciu kilowoltów na mikrosekundę i częstotliwość dziesiątków kiloherców. I choć technologia ta ma wyraźne zalety dla regulacji prędkości obrotowej napędów, fale napięciowe generowane przez przemienniki mogą znacząco wpływać na trwałość układu izolacyjnego maszyny. Dla poprawy zrozumienia procesów starzeniowych układu izolacyjnego zachodzących w trakcie impulsów napięciowych koniecznym jest monitorowanie wartości elektrycznych występujących w czasie trwania impulsu. Dla analizowania starzenia izolacji głównej wybrano takie parametry jak: współczynnik rozproszenia, pojemność, prąd absorpcji i resorbcji, napięcie początkowe korony, i poziom wyładowań niezupełnych. Te parametry są łatwe do pomiaru a ich przebiegi są dobrze znane dla procesów starzeniowych od napięcia sinusoidalnego. W artykule przedstawiono zależności czasu starzenia układu izolacji skutkiem działania napięcia sinusoidalnego i starzenia izolacji od impulsów napięciowych.
This article presents information about issues requiring particular attention during thermal tests of electrical machines. It presents mistakes that can be made and describes the influence of parameters such as: relative humidity, reflected temperature, atmospheric temperature, distance from an object and emissivity, on the results of the tests
The article presents short history (2001-2006) of diagnostic of insulation using dc-voltage method. The diagnostic was made on the middle voltage AC-motors. The paper describes method of DC-voltage and shows criterion of estimation. The paper presents results of diagnostics and trends of changes proseed in insulation of mantiend motors for e few years. Authors shows that is possible to predict the damage of the motor and reduce the costs of repairs.
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