Diagnostics of electric motors technical condition using wavelet analysis

Author(s):  
O. Bolshunova ◽  
A. Kamyshian ◽  
A. Bolshunov
2020 ◽  
pp. 43-50
Author(s):  
A.S. Komshin ◽  
K.G. Potapov ◽  
V.I. Pronyakin ◽  
A.B. Syritskii

The paper presents an alternative approach to metrological support and assessment of the technical condition of rolling bearings in operation. The analysis of existing approaches, including methods of vibration diagnostics, envelope analysis, wavelet analysis, etc. Considers the possibility of applying a phase-chronometric method for support on the basis of neurodiagnostics bearing life cycle on the basis of the unified format of measurement information. The possibility of diagnosing a rolling bearing when analyzing measurement information from the shaft and separator was evaluated.


Author(s):  
Ildar Yamansarin ◽  
◽  
Mikhail Salikov ◽  
Alexander Padeev ◽  
Dmitry Surkov ◽  
...  

The article deals with the issues related to the possibility of diagnosing the technical condition of an asyn-chronous electric motor by an external magnetic field. The justification of the problems associated with the di-agnosis of electric motors is given. The difficulties that arise when measuring the external magnetic field of electric motors, as well as the devices with which it is possible to carry out measurements, are described. The re-lationship between the EMF of the sensor and the external magnetic field is shown. The results of processing the EMF waveforms induced by an external magnetic field in an inductive sensor for various electric motors are presented. The processing was carried out by the fast Fourier transform method. The external magnetic field contains the first harmonic and various harmonics that are multiples of the combination of the stator teeth, or the sum of the stator and rotor teeth that fall on one pair of poles. The ratio of the amplitudes of the first and tooth harmonics is affected by the measurement location and the orientation of the sensor. Diagrams showing the ratio of the main and tooth harmonics at different points of the motor body are constructed. The depend-ences of the harmonic amplitudes on the magnitude of the magnetizing current of the stator are given. Changes in the amplitudes and spectrum of harmonics in the presence and absence of an inter-turn short circuit in the stator winding are shown. Diagrams of the circular external magnetic field for the main and higher harmonics are constructed. The study shows the possibility of using an external magnetic field to detect inter-turn short circuits of the stator winding.


Designs ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 52
Author(s):  
Vladimir Sakharov ◽  
Sergei Chernyi ◽  
Sergey Saburov ◽  
Aleksandr Chertkov

The use of digital technologies in the systems of diagnostics and monitoring of units of a ship’s propulsion plant can significantly increase the efficiency and quality of assessing the technical condition of operated objects in the online mode as well as expand the class of practical problems to be solved. Digital processing of signals of complex configuration at a qualitatively new level is an indispensable condition for a critical improvement in the course of processing the current values of diagnosable parameters, increasing the reliability and trouble-free performance of a ship’s technical equipment during operation. A method of approximation has been discussed in the paper. Moreover, the paper provides an algorithm for analyzing the signal of the indicator diagram of a marine diesel engine, the spectrum of which contains high-frequency components and short-term pulses indicating deviations from the normal operating mode, the assessment of which is practically impossible with the traditionally applied methods of spectral analysis of signals. The approximation method is based on the use of wavelet analysis, which makes it possible to deeply explore such modes. Examples of using wavelet analysis to approximate one-dimensional signals of elements and systems of a ship’s power complexes are given.


2019 ◽  
pp. 52-58
Author(s):  
A. B. Vasenin ◽  
S. E. Stepanov ◽  
O. V. Kryukov

The present technical condition of the fleet of electric motors serving the actuators of the infrastructure facilities of the fuel and energy complex is presented. The statistics of damage and damage from abnormal operation of electric drive units operating on mechanisms with a fan and pump load are given. The analysis of the causes of the increase in the range of vibration displacement, which leads to premature failure of electric motors, is given. A method for reliably determining the causes of damage, based on measuring and analyzing the electrical parameters of the harmonic spectrum of the motor current, is proposed. Its essence consists in creation of the universal diagnostic system working at the physical principle at which any indignations in work of an electric and mechanical part of the engine and related actuator lead to modulation of the consumed current. Existence in a range of current of characteristic frequencies of a certain size demonstrates existence of these or those damages. The device for its implementation includes phase current sensors of the supply voltage, a signal conditioner for normalizing and filtering signals, an analog-to-digital converter with a USB interface, and a controller with software for analyzing, evaluating, and diagnosing the condition. Experimental results have been obtained confirming the adequacy of the methodology and technical means for monitoring electric motors of various mechanisms.


2021 ◽  
Vol 18 (3) ◽  
pp. 393-401
Author(s):  
Denis Yu. DROGOLOV ◽  
◽  
Pavel V. SOKOLOV ◽  
Alexey S. KUSHNIRUK ◽  
◽  
...  

Objective: Optimization of the rates of overhaul runs on the basis of the results of the study of the distribution of failures of traction motors caused by a critical decrease in the insulation resistance of the windings to reduce the cost of eliminating the consequences of unscheduled repairs of locomotives. Methods: Mathematical statistics, probability theory, theory of reliability of technical systems are applied. Results: A cause-and-effect analysis was carried out of cases when locomotives were placed for unscheduled repairs in 2019–2020. An element has been determined that limits the rates of overhaul mileage of traction electric motors of locomotives. The theoretical distribution of failures of traction electric motors due to a critical decrease in the insulation resistance of its windings is obtained. The optimization of the norms of overhaul runs of locomotives was carried out according to the conditions of current repairs in the amount of TR-2 relative to traction electric motors. It was revealed that the failures are mainly associated with the first period of operation of traction motors. As a result of the analysis of the reasons for the failure of traction electric motors, it was found that most cases of unscheduled repairs fall on the first interval of locomotive runs due to the poor quality of repairs. In this case, the first normal peak of failures falls on the mileage in the modal interval from 156 to 234 thousand kilometers, when the overhaul mileage on TP-2 is 250 thousand kilometers, which necessitates its optimization within the preceding modal interval. Practical importance: The presented version of optimization of overhaul runs can be used to determine the rationality of establishing the norms for the periods of maintenance and repair operations on locomotive units under the conditions of a planned preventive control system for their technical condition


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