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Author

Virgiliu Fireteanu

Other affiliations: University of Bucharest
Bio: Virgiliu Fireteanu is an academic researcher from Politehnica University of Bucharest. The author has contributed to research in topics: Induction motor & Rotor (electric). The author has an hindex of 9, co-authored 57 publications receiving 246 citations. Previous affiliations of Virgiliu Fireteanu include University of Bucharest.


Papers
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Proceedings ArticleDOI
03 May 2007
TL;DR: In this article, the optimal design of squirrel cage rotor slots and copper bars of high power induction motors with respect to the values of starting torque, breakdown torque, rated values of efficiency and power factor as well as rotor heating is discussed.
Abstract: This paper deals with the optimal design of squirrel- cage rotor slots and copper bars of high power induction motors with respect to the values of starting torque, breakdown torque, rated values of efficiency and power factor as well as rotor heating. Three geometries of rotor slots and of bars cross-section, keeping the same cross-section area, are considered: rectangular shape, stepped shape and step-holed shape. This study is based on the finite element analysis of the induction motor where only the rotor slots and bars cross-section configurations change from an application to another. The comparison of simulation results proves that important increase of starting torque and high values of efficiency of copper squirrel-cage type induction motors can be obtained in case of step-holed shape of rotor bars cross-section, without significant decrease of the breakdown torque. Criteria for evaluation of optimal geometry of rotor bars and of optimal value of bars cross-section area are studied.

31 citations

Proceedings ArticleDOI
01 Nov 2011
TL;DR: In this paper, the influence of different faults of a squirrel-cage rotor in induction motors on the near-magnetic field is studied. And the 2D finite element analysis of electromagnetic field is used to investigate the detection of broken rotor bars and rotor eccentricity faults.
Abstract: The influence of different faults of squirrel-cage rotor in induction motors on the near-magnetic field are studied in this paper. The 2D finite element analysis of electromagnetic field is used to investigate the detection of broken rotor bars and rotor eccentricity faults. This analysis is focused on the low frequency harmonics of the near-magnetic field, which are much modified under faulty conditions and less attenuated by the motor frame.

15 citations

Proceedings ArticleDOI
01 Sep 2008
TL;DR: In this paper, the teaching of electromagnetic structure of induction machine, of steady state characteristics and of dynamic and transient machine behaviors based on finite element models and analysis of simulation results is discussed.
Abstract: This paper refers to the teaching of electromagnetic structure of induction machine, of steady state characteristics and of dynamic and transient machine behaviors based on finite element models and analysis of simulation results. Magnetoharmonic and transient models are used to solve field-circuit, respectively field-circuit-rotating motion problems.

13 citations

Proceedings ArticleDOI
23 May 2013
TL;DR: In this article, the effects of short-circuit faults in the stator winding of an induction motor and the influence of this fault on the magnetic field outside the motor were investigated.
Abstract: Based on the finite element analysis of the electromagnetic field in time domain, this paper studies effects of the short-circuit faults in the stator winding of an induction motor and the influence of this fault on the magnetic field outside the motor. The detection of the short-circuit fault through the magnetic field is based on the comparison of harmonics of the output voltage of coil sensors for the healthy and faulty motor states. The influence of the magnetic saturation of the motor on the fault diagnose efficiency is studied.

13 citations

Proceedings ArticleDOI
01 Aug 2013
TL;DR: In this paper, the effects of the short-circuit fault in the stator winding of an induction motor and the influence of this fault on the magnetic field outside the motor were investigated.
Abstract: Based on a time domain finite element analysis of the electromagnetic field, the paper studies effects of the short-circuit fault in the stator winding of an induction motor and the influence of this fault on the magnetic field outside the motor. The detection of the short-circuit fault through the magnetic field in the motor neighboring is based on the comparison of harmonics of the output voltage of coil sensors in the healthy and faulty motor states. The influence of the motor frame on the efficiency of fault detection is studied.

12 citations


Cited by
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Journal ArticleDOI
TL;DR: This paper reviews IH technology summarizing the main milestones in its development and analyzing the current state of art of IH systems in industrial, domestic, and medical applications, paying special attention to the key enabling technologies involved.
Abstract: Induction heating (IH) technology is nowadays the heating technology of choice in many industrial, domestic, and medical applications due to its advantages regarding efficiency, fast heating, safety, cleanness, and accurate control. Advances in key technologies, i.e., power electronics, control techniques, and magnetic component design, have allowed the development of highly reliable and cost-effective systems, making this technology readily available and ubiquitous. This paper reviews IH technology summarizing the main milestones in its development and analyzing the current state of art of IH systems in industrial, domestic, and medical applications, paying special attention to the key enabling technologies involved. Finally, an overview of future research trends and challenges is given, highlighting the promising future of IH technology.

559 citations

Proceedings ArticleDOI
11 Mar 2013
TL;DR: An overview of typical failure mechanisms and their causes is presented in this article, where recent advances and future perspectives are discussed as well as important and fundamental papers are reviewed and reported in a comprehensive list of references.
Abstract: This paper investigates diagnostic techniques for electrical machines with special reference to rotor faults in induction motors. An overview of typical failure mechanisms and their causes is presented. Also recent advances and future perspectives are discussed. To this aim the most recent related works along with important and fundamental papers are reviewed and reported in a comprehensive list of references.

105 citations

Proceedings ArticleDOI
11 Mar 2013
TL;DR: In this article, a simple model of the external magnetic field is presented and a study in healthy and faulty conditions is developed for stator inter-turn short-circuit and rotor broken bar.
Abstract: The stray flux in the vicinity of an electrical machine is inherent to its running. It is tied to the magnetic state of the machine and therefore can be affected by the presence of a fault in the machine. Accurate modeling of the external magnetic field is quite complicated and simple models are required in order to analyze the effect of an internal fault on the stray flux. This paper displays the possibilities offers by the stray flux for fault detection. A simple model of the external magnetic field is presented and a study in healthy and faulty conditions is developed. Two kind of fault in induction machine are considered: stator inter-turn short-circuit and rotor broken bar. Experimental results are in agreement with the theory, they highlight the differentiation between the radial flux and the axial flux.

96 citations

Journal ArticleDOI
TL;DR: In this paper, numerical mixed-dimensional models, composed of multiple high-aspect-ratio thin layers, are developed to study the underlying behavior that drives quench propagation at the micrometer-scale level.
Abstract: YBa2Cu3O7-δ coated conductors have very slow normal-zone propagation velocity, which renders quench detection and protection very difficult. To develop effective quench detection methods, it is paramount to study the underlying behavior that drives quench propagation at the micrometer-scale level. Toward this end, numerical mixed-dimensional models, composed of multiple high-aspect-ratio thin layers, are developed. The high-aspect-ratio modeling issues are tackled by approximating the thin layers either as a 2-D surface or as an analytical contact resistance interior boundary condition, which also acts as a coupling bridge between the 2-D and 3-D behaviors. The tape models take into account the thermal and electrical physics of each layer in actual conductor dimensions and are implemented using commercial finite-element analysis software. In the first part of this two-part paper, the mixed-dimensional models are introduced and then computationally and experimentally validated. Validations are gauged by comparisons in normal-zone propagation velocity and in the time-dependent voltage and temperature profiles. Results show that the mixed-dimensional models can not only effectively address the high-aspect-ratio modeling issues of thin films but also accurately and efficiently reproduce physical quench phenomena in a coated conductor.

75 citations

Journal ArticleDOI
TL;DR: The design flexibility of the proposed method is confirmed to obtain National Electrical Manufacturers Association (NEMA) designs satisfying different torque characteristics.
Abstract: Induction motors are widely used in various industrial applications with different torque-speed characteristics. Since the configuration of the rotor slot has a great impact on the electromagnetic torque-speed characteristics, a design optimization process is necessary to improve the motor performance of the induction motor. The material boundaries of the rotor slot are represented by a level set function, and a voltage driven time-harmonic field analysis is performed to estimate the characteristics of the induction motor. An optimization problem is formulated to maximize the torque at one speed either a rated or starting condition constrained by the torque at other speeds, starting currents and efficiency. A level set equation with an augmented Lagrangian method is derived to find the optimal design. Optimal results are achieved by updating the sequential changes of the material region driven by the shape derivative. The design flexibility of the proposed method is confirmed to obtain National Electrical Manufacturers Association (NEMA) designs satisfying different torque characteristics.

61 citations