The summary of the article An Improved Model of Induction Motors for Diagnosis Purposes – Slot Skewing Effect and Air–Gap Eccentricity Faults by Ghoggal, Zouzou, Razik, Sahraoui, and Khezzar in the journal Energy Conversion and Management will be presented in this paper. This paper will seek to provide a succinct summary of the key constructs of this research journal.
This paper offers a description of an improved method for modeling of axial and radial eccentricities in IM taking into account that induction motors remain a major concern in the engineering and related fields. The reasons that deal with the approach of new and improved description are clearly pointed out in this research paper.
First of all, there is a need to improve levels of reliability in IM. Secondly, engineers in all the fields grapple with a problem to improve operational safety and reduce costs in production. The authors posit that these objectives can be only achieved by acquiring the capacity to detect upcoming abnormalities. as a matter of fact, this article proposes a number of new features of sensor signals that have the capacity to detect faults and provide online protection of IM.
The differentiating factor in this proposed model of improved IM is that most of the works devoted to the detection of faults are related to the current harmonics derive equations from the winding function approach (WFA). However, this theory is an extension of WFA to MWFA which encompasses radial eccentricity modeling.
The authors support the works of other researchers in providing additional benefits from the improved IM. According to Goggle et al (1336), this approach “was found powerful because of its ability to consider, jointly or separately, the opening and skewing of the slots, the magnetic saturation, and the flux distortion due to the air–gap permeance effect with a relatively small computational time.”
There is a general abidance in the fact that quite a few studies have incorporated MWFA in radial eccentricity modeling. In adopting static, dynamic, and mixed eccentricity, this model proves the need for p-harmonic in delivery of better results. A great deal of literature fail to incorporate “the case of dynamic and mixed axial eccentricity, the inductance plots and the associated transient behaviors of the motor” (Ghoggal, Zouzou, Razik, Sahraoui, and Khezzar 1337).
Precise geometrical models must be used for extra terms of expansion of inverse of air-gap function given on the understanding that IM has a large number of poles. The successful achievement of these two objectives forms the main purposes of this research study.
Transient Model of the IM
When making use of the assumptions that permeance of the iron is infinite, there are no inter-bar currents and winding losses, eddy currents and corps saturation are negligible.
The authors argue that voltage and mechanical equations of the loaded IM in the case of a triple phase stator winding can be established. The authors of the article offer interesting calculations for inductances, such as types of eccentricities and global formulation, to demonstrate a shift from static, dynamic, and mixed eccentricity radial to a more precise geometrical model.
Simulation Results and Paper Analysis
The authors have stated an appropriate topic that made it clear what issues were to be discussed in the paper. The successful development of an extended form of MWFA under conditions that the motor is healthy or faulty is a clear indication of this fact. This essay is an accurate and comprehensive summarization of the entire thesis and works in tandem with the simulation results of the study.
The authors have also presented a clear introduction that clearly introduces the topic of research where the thesis statement has been explicitly stated. This involved the presentation of the existing gaps in the literature which are the reasons for the study.
The proposed model comes along with a number of capacities that reinforce the importance and significance of this study. According to Goggle et al (1338), the method enabled the “calculation of IM inductances taking into account, first, the harmonics due to the non-sinusoidal distribution of the MMF in the air–gap and, secondly, the effects of rotor bar skewing and the resultant linear rise of MMF across the slots.” The simplification of the integrals leading to the machine was achieved through the adoption of a plane representation in IM.
An organization of the thesis and the major headings under discussion has also been presented that helps the reader to understand the flow of the thesis. The literature review is detailed and accurate and hits the point. Unnecessary citations have not been presented, that’s why all the results are exact and consistent.
The methodology used in the article is also appropriate for the research as it follows a clear synthesis of the major findings which have been presented by various authors on the topic under discussion, based on empirical as well as theoretical research. The discussion represented in the article is detailed, comprehensive, and informative and helps the reader to understand the issues that are presented in the interpretation of the results that are concerned.
The strongest parts of the study are the introduction of the precise geometrical model or extra terms of the expansion of the inverse of the air–gap function. Furthermore, the injection of the acquired voltage data into the simulation tool offers a chance for the inclusion of the harmonics power supply.
The authors do not only give detailed information on these important aspects of this study but offer a simple approach through which inductances calculation on types of eccentricities and global formulation can be achieved. The authors also expound the calculation of the inductance providing and representing detailed examples and scenarios where they fit the precise geometrical models.
These form the strongest parts of the study as they seek to demonstrate that the authors have achieved a shift from WFA to MWFA. The conclusion and future research have also been succinctly presented, based on dissemination of the key findings generated from the research.
Perhaps, the study would have been better and more detailed if the models that can be applicable in the future had been proposed. This would have provided a firm foundation of the case of future research. However, based on the transient simulation and related inductances calculations, the accomplishment of relevant experiments have been achieved. This offers a breakthrough in a case that is of great importance to engineers in all the fields.
The advantages of the proposed model revolve around the understanding that it does not demand huge computational capacity and provides a firm basis for the development of even more precise geometrical models than the existing ones in the future. Improvements in reliability, safety, and reduction in production have been achieved due to this model.
Ghoggal, Adel, Zouzou, S.E., Razik, H., Sahraoui, M. and A. Khezzar. “An improved model of induction motors for diagnosis purposes – Slot skewing effect and air–gap eccentricity faults.” Energy Conversion and Management May 2009: 50 (1), 1336–1347.