Renewal coil insulation systems for AC stator windings

Author(s):  
H. C. Lauroesch
Vestnik MGTU ◽  
2021 ◽  
Vol 24 (4) ◽  
pp. 361-371
Author(s):  
A. I. Kashin ◽  
A. E. Nemirovsky

This work is a continuation of the fundamental study on implementing an innovative method of repairing electric motors using ultrasound. A study of the method of dismantling windings based on ultrasound has been carried out for the purpose of energy efficiency, environmental friendliness and less time spent on the repair cycle of electric motors in terms of removing the stator winding. The investigated dismantling method is optimal for a number of technical issues in comparison with the existing methods for dismantling electric motor windings. In the work, the main focus is on the material of the winding insulation. Lacquer and compound types of insulation of industrial electric motors, which are the main ones everywhere, have been analyzed. The analysis of the impregnating electrical insulating compositions of the stator windings of electric motors and the influence of ultrasound on them during dismantling of the windings of electric motors at different levels of influence of forcing factors: duration and power of ultrasonic action, concentration and temperature of the working solution. The applied mathematical software systems for calculation and modeling guarantee the reliability and rationality of the results of the experiments obtained during the work. A system of equations has been modeled and models of the effect of useful factors relative to each other have been constructed, the results obtained have been optimized and the optimal parameters of both varnish and compound insulation systems have been identified. The optimal parameters of the investigated types of insulation show encouraging results on many important points: duration, energy consumption, environmental friendliness.


Vestnik MGTU ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 354-363
Author(s):  
A. E. Nemirovsky ◽  
A. I. Kashin

For the purposes of energy efficiency, ecology and less time for the cycle of repairing electric motors in the part of the excavation of the stator winding, an innovative method for dismantling ultrasound-based windings has been investigated. From a technical point of view the method has shown to be more optimal in comparison with existing methods of removing the winding. The paper is a continuation of fundamental research on the development of an innovative method of repairing electric motors. It is in this article that the main emphasis is placed on the material from which the insulation of windings is made. Lacquer and compound insulations have been considered being the main types of insulation of industrial electric motors in our country. The analysis of impregnating electrical insulation compositions of motor stator windings has been carried out; the ultrasound effect during the dismantling of motor windings at different levels of influencing factors has been studied, namely duration and power of ultrasonic action, concentration and temperature of the working solution. The validity of the scientific results obtained in the work is confirmed by the correctness of the applied mathematical apparatus and the methods of mathematical modeling, the convergence of the results of numerical modeling and full-scale experiments. A system of equations has been simulated and models of the effect of useful factors relative to each other have been built, the results obtained have been optimized during the experiment and the optimal parameters of both lacquer and compound insulation systems have been identified. The optimal parameters of the types of insulation under study have shown encouraging results on many important points compared to the existing ones: duration, energy consumption, and environmental friendliness. The validity of the conclusions regarding the adequacy of the mathematical models used has been confirmed by the results of experimental studies conducted in the framework of this work of the process of depolymerization of the electric motors' stator windings.


1984 ◽  
Vol 45 (C1) ◽  
pp. C1-615-C1-617
Author(s):  
H. Becker ◽  
P. G. Marston

2013 ◽  
Vol 62 (4) ◽  
pp. 605-612
Author(s):  
Marek Szmechta ◽  
Tomasz Boczar ◽  
Dariusz Zmarzły

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.


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