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The concept of Predictive Maintenance includes techniques based on developing a periodic or continuous follow-up of the state of any device, for predicting faults with certain anticipation. As essential part of this activity, are the essays of diagnosis to the machines and most important equipments of an installation. It is known that the power factor of isolation, it is a parameter that offers valuable information of the state of the insulating system of the electric machines in general and of the transformers in particular. In this article the results of the measurements of power factor of isolation of three power transformers of three windings of subtransmission substations of 110/34,5/6,3 kV are presented. Information that recommends the immediate intervention on some studied cases in avoidance of exits on duty by damages is given. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Concreta is the property of Editorial Concreta and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The tests that are carried out to electric machines need of: taking of data, their prosecution and determination of their parameters or performances. All that you can automate, being more important if it is about repetitive processes. In this work the open circuit, short circuit and zero power factor tests of a synchronous machine were automated in what concerns to obtaining data for determines the generator performance relative to its voltage regulation utilizing Potier method. It utilizes a very simple hardware based on an acquisition card in orde to introduce them to a computer and by means of a software implemented in Matlab, to determine the regulation of voltage. In order to simplify the calculations, an analytic method is used instead of the known graphical method. The proposed method can be introduced in the Electric Machines Laboratories without changing the existent equipment. [ABSTRACT FROM AUTHOR]

The work evaluated the technological and exploitation indicators of the CASE IH Austoft 8000 sugarcane harvesters used in the CAI Heriberto Duquesne de Villa Clara, during the period of time between the months of March to May 2019. For the study was used the methodological basis necessary to characterize the climatic conditions of exploitation, to evaluate the training of the combine drivers and through the Cuban Standard IAgric (2013), determine their technological and exploitation indicators in the given conditions, harvesting different varieties of cane. As a result, it was shown that the weather conditions in the area did not have any influence on the work of these machines and that the preparation of the combine drivers is adequate. However, they worked with technological and operating indicators that should and can be improved if for this purpose they are able to reduce the times for the performing of daily technical maintenance (T31) and fundamentally to eliminate technical failures (T42). [ABSTRACT FROM AUTHOR]

A good electric engineer should not only know and to be up-to-date of the new technologies, but rather he should know how that wonderful world of the technique was born effective today; the electric machines are the heart of the modern life, transformers, motors and electric generators, those that daily facilitate us the life filling each corner. it is objective to bring near to that luminous birth of the modern world where the electricity began to be everything for each human of this planet. In that birth of the electric power like part of each citizen's life day by day, and in the fact of being constituted an unit of measurement of the development of each country, the Exhibition of Paris went without place to doubts, a key factor. Starting from 1889 the man discovered the reality of living a dream: it's borning the machines and electric driving. [ABSTRACT FROM AUTHOR]

The present work was developed in the United Basic Cooperative Production (UBPC) “Marcos Martí” and “Williams Soler” of the Agricultural Enterprise “April 19”, Mayabeque province, during the 2017-18 potato campaign with the objective of determining the technical-economic parameters in central pivot machines and its influence on crop yield. The evaluation was carried out on Valmont 1-2 and Urapivot 2-3 machines, following the methodology proposed in NC ISO 11 545 for the evaluation of pivots, where the uniformity coefficient is decisive for the definition of irrigation quality. The incidence of irrigation in crop yields was also analyzed. The results obtained show the Uniformity Coefficient in the whole machine and its behavior between towers allowed it to define the sections where measures for improvement should be applied, taking into account that this equipment have been in operation between 13 and 18 years. For de the Valmont machine were classified as 86,67% as good and Urapivot as 79,10% as bad. In the economic analysis, it was found that the uniformity coefficient affects the operating parameters since, by improving the quality of irrigation and the standards applied, yields between 30,14 and 27,41 t∙ha-1 are achieved. The cost benefit ratio in the machines studied was 0,92 and 0,97, both values lower than the unit, which indicates the non-profitability irrigation management in the campaign studied. [ABSTRACT FROM AUTHOR]

Copyright of Revista Española de Sociología is the property of Federacion Espanola de Sociologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The stator core of an electric machine for teaching applications, with 12 teeth and open slots, is used and a rotor, of sintered magnetic material, is constructed to configure a flux switching three-phase heteropolar inductor alternator. The optimization of the rotor design consists of obtaining the best number of teeth that provides a waveform of the output voltage closest to a sinusoidal function and with a higher effective value (rms). An analytical model is presented, allowing to establish a comparison of the values of the permeances, depending on the number of teeth of the rotor. Results are compared with simulation values, using a finite element program. The conclusion reached is that seven is the ideal number of teeth and slots of the rotor. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Lengua para Fines Específicos is the property of Revista de Lengua para Fines Especificos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study was performed in Sugar Mill Antonio Guiteras Holmes, municipality Puerto Padre, Las Tunas province in the 2012 harvest, the behaviour of induction motors Mills on current operating conditions with the knowledge of the measurements of the electrical parameters is evaluated voltage, current and power factor with these minimum elements and applying the method of their energy data badges indicators were obtained, these results allowed us to know the load factor, efficiency, the actual power output of the engine to achieve standards a more rational and efficient energy use in the company. A proposal for resizing these engines is performed. [ABSTRACT FROM AUTHOR]

This document presents the study results of the wavelet 1D multi-level decomposition of perturbed electromagnetic torque and shaft speed signals, of the three-phase induction motor, when it is subjected to different types of voltage sags, as characterization ABC, Bollen (2000). The three-phase voltage sags (3 variables) are analyzed in the effect on a perturbed variable (the electromagnetic torque and mechanical speed) that contains indirect information from the voltage sag occurred in the stator. The study examines seven different types of voltage sags, also considering the influence of duration and retained voltage. For each case, a vector whose elements are the energy levels at different wavelet decomposition levels of the analyzed variable is obtained, showing that the way 1D signal energy is distributed at different levels of decomposition set a unique signature for each case. This form of description of the voltage sags, produced in the stator, based on the multi-level decomposition, reduces the amount of variables to be analyzed and subsequently allows the classification of the disturbances using artificial intelligence techniques; storage is advantageous because the vectors of energy levels of approximation in databases used less amount of space required for a temporary signal, and employing a reversible DWZ, it's also possible to reconstruct the state variable. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As an alternative in the energetic utilization of energy of periodical nature, it becomes a study of generators to use directly the movements translational, without the need to make conversions to rotational energy. The operation of the generator is based on the law of induction of Faraday, in the same way that makes all the electrical machines. This document is focused on the use of the waves as part of the tidal power, it is therefore requires the implementation of some concepts of the hydrostatic and statistical data of the waves for a supposed place of mounting the machine. With the previous information is developed a program in Matlab® to provide the necessary data for the subsequent design of the machine. [ABSTRACT FROM AUTHOR]

The article robustness, simplicity and maintenance of asynchronous motors. These motors occasionally suffer mishaps but are possible to change when repaired under certain design parameters. Their original data are significant in repairing even without following a method with basements in the design of the electric machines. A calculation software was established for annoying calculations of redesigning these machines and of changing speed and voltage operation frequency.