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Article
Publication date: 1 April 2006

J. Gyselinck and X.M. López‐Fernández

To study the inclusion of inter‐bar (IB) currents in a multi‐slice finite element (FE) model of induction motors and in particular the effect of the associated skew…

Abstract

Purpose

To study the inclusion of inter‐bar (IB) currents in a multi‐slice finite element (FE) model of induction motors and in particular the effect of the associated skew discretisation. To validate the model experimentally.

Design/methodology/approach

Both a classical uniform distribution and a gauss distribution of the slices and the lumped IB resistances are considered. Measurements on a 3 kW induction motor allows one to estimate its IB resistance and to validate the FE model.

Findings

A gauss distribution of the slices allows one to use fewer slices and thus reduces the computational cost. The simulation results show that, at full load, skew changes the different loss components significantly, while the IB currents have a minor effect.

Research limitations/implications

The direct measurement of the IB resistance is by no means trivial. In the frame of this paper, it was indirectly determined, namely by means of a short‐circuit test.

Originality/value

The gauss distribution of the slices and the IB resistance; the systematic study of the skew discretisation; the experimental determination of the IB resistance.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 26 August 2014

Rosario Miceli, Yasser Gritli, Antonino Di Tommaso, Fiorenzo Filippetti and Claudio Rossi

The purpose of this paper is to present a diagnosis technique, for rotor broken bar in double cage induction motor, based on advanced use of wavelet transform analysis. The…

Abstract

Purpose

The purpose of this paper is to present a diagnosis technique, for rotor broken bar in double cage induction motor, based on advanced use of wavelet transform analysis. The proposed technique is experimentally validated.

Design/methodology/approach

The proposed approach is based on a combined use of frequency sliding and wavelet transform analysis, to isolate the contribution of the rotor fault components issued from vibration signals in a single frequency band.

Findings

The proposed technique is reliable for tracking the rotor fault components over time-frequency domain. The quantitative analysis results based on this technique are the proof of its robustness.

Research limitations/implications

The validity of the proposed diagnosis approach is not limited to the analysis under steady-state operating conditions, but also for time-varying conditions where rotor fault components are spread in a wide frequency range.

Practical implications

The developed approach is best suited for automotive or high power traction systems, in which safe-operating and availability are mandatory.

Originality/value

The paper presents a diagnosis technique for rotor broken bar in double cage induction motor base on advanced use of wavelet transform which allows the extraction of the most relevant rotor fault component issued from axial vibration signal and clamping it in a single frequency bandwidth, avoiding confusions with other components and false interpretations.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 19 November 2021

Amir Darjazini, Abolfazl Vahedi, Amin Nobahari and Saber Gharehseyed

Pulsating torques cause a number of problems in electrical machines, including mechanical vibrations, acoustic noise and the depreciation of mechanical equipment. In induction…

Abstract

Purpose

Pulsating torques cause a number of problems in electrical machines, including mechanical vibrations, acoustic noise and the depreciation of mechanical equipment. In induction motors, the slot skewing method is an effective way to solve these issues; however, it has some drawbacks such as output torque drop, stray loss intensification due to inter-bar currents and iron loss increment. Besides, slot skewing may not be practical in higher-rated induction motors. In this regard, this paper introduces a modified non-skewed rotor (MNSR) structure as a possible alternative to the skewed designs.

Design/methodology/approach

The proposed structure includes a two-segmented rotor with an intermediate ring between the rotor parts that are mounted on the shaft with a relative shift angle. Detailed information about the idea and structure of the MNSR as well as its manufacturing aspects will be presented in the second section of the paper. First, the working principle of the proposed design is described via analytical equations to provide an insight into the concept. The shifting angle will then be calculated by analyzing the harmonic contents of the electromagnetic torque. Finally, the validity of the analytical method will be verified by developing three-dimensional finite element models.

Findings

It is demonstrated that by using the proposed rotor structure, the torque ripple has been reduced to a satisfactory level without significantly affecting the mean torque, unlike the skewing method. Furthermore, the new method could avoid the disadvantages of the skewing method while enhancing other motor characteristics such as iron loss. Also, the total volume of the MNSR is equal to the initial design, and the mass and material differences are also negligible.

Originality/value

In this paper, a MNSR is introduced as a possible alternative to the skewed patterns. The study mainly focused on electromagnetic torque profile characteristics, i.e. the mean torque enhancement and the ripple reduction. The MNSR structure can be used for general purposes and high-performance applications, especially where excellent torque characteristics are required.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 41 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 2 January 2018

Ashish Kumar Sinha, Sukanta Das and Tarun Kumar Chatterjee

Condition monitoring of squirrel cage induction motors (SCIMs) is indispensible for achieving fault-free working environment. As broken rotor bars (BRBs) are one of the more…

Abstract

Purpose

Condition monitoring of squirrel cage induction motors (SCIMs) is indispensible for achieving fault-free working environment. As broken rotor bars (BRBs) are one of the more frequent faults in a SCIM especially where direct-on-line starting is indispensible, as in underground mines, a priori knowledge of fault severity in terms of the number of BRBs assists in effective fault monitoring. In this regard, this paper aims to propose a unique empirical relation to facilitate the determination of number of BRB.

Design/methodology/approach

Fast Fourier transform is used to obtain fault sideband amplitudes under varying number of BRBs and load torque for 5.5 kW, 7.5 kW, 10 kW, three-phase, 415 V, 50 Hz SCIMs in MATLAB/Simulink. The nature of variation is decided by an appropriate curve fitting technique for comprehending a unique empirical relation. The proposed empirical relation is validated by bootstrapping and z-test. Furthermore, hardware validation is done using 1 kW laboratory prototype with Labview interface.

Findings

The analytical study reveals the dependence of lower and upper sideband amplitudes on the number of BRBs, load torque and machine rating. Therefore, fault severity in terms of number of BRBs is accurately calculated using the proposed empirical relation if load torque, machine rating and amplitudes of lower and upper sidebands are known.

Originality/value

The unique empirical relation proposed in the present work provides accurate knowledge of fault severity in terms of the number of BRBs. This facilitates maintenance scheduling which shall reduce effective downtime and improve production.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 3 January 2017

Yoshihiro Kawase, Tadashi Yamaguchi, Yoshiki Iwai, Koki Akiyama, Naotaka Toida, Tomoyasu Furukawa and Hiroshi Kawano

The interbar current of a squirrel-cage induction motor (IM) flows in the steel sheets when the secondary conductor is not insulated from the laminated steel sheets. It was…

Abstract

Purpose

The interbar current of a squirrel-cage induction motor (IM) flows in the steel sheets when the secondary conductor is not insulated from the laminated steel sheets. It was reported that the interbar current loss was increased when skewing the rotor core. This paper aims to analyze a skewed IM using the three-dimensional (3D) finite element method. The effects of rotor skew on the interbar current are clarified.

Design/methodology/approach

In this paper, a skewed squirrel-cage IM is analyzed in three patterns of skewed angle. The calculated results were compared with each other. If all laminated steel sheets are divided by the mesh with actual thickness, the huge calculation time is required. In the method applied in the study, several steel sheets are divided by the mesh with the actual thickness and some steel sheets are assumed to be the steel lump between them to shorten the calculation time.

Findings

The paper describes that the distribution of interbar current loss when rotor is skewed is different from that when rotor is not skewed. In addition, the paper suggests that the larger the skew angle becomes, the larger the interbar current loss becomes.

Originality/value

In this paper, a skewed IM with the consideration of the interbar current in the laminated steel sheets was analyzed using the 3D finite element method. The influences of the rotor skew on the interbar current are clarified.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Content available
Article
Publication date: 1 April 2006

M. Dems and K. Komeza

269

Abstract

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 2
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 1 January 2013

José Antonio Barrado Rodrigo, Xavier Munté Puig, Hugo Valderrama Blavi and Luis Guasch Pesquer

The purpose of this paper is to develop and test a prototype of the dual stator‐winding induction generator (DWIG) and its dynamic model to verify the validity of this machine…

Abstract

Purpose

The purpose of this paper is to develop and test a prototype of the dual stator‐winding induction generator (DWIG) and its dynamic model to verify the validity of this machine design as variable speed generator for renewable energy systems.

Design/methodology/approach

Implementation and laboratory test of a DWIG prototype. Analysis and simulation of the developed DWIG model.

Findings

The proposed DWIG makes a better use of energy than a squirrel cage induction generator (SCIG) in variable speed applications. The performance of DWIG with a bidirectional converter is very similar to those described in other studies with brushless doubly‐fed induction generators.

Research limitations/implications

The results can be used to test different control techniques and to analyse the dynamic performance of DWIG‐converter system in variable load and speed conditions.

Originality/value

The stator winding design does not involve a significant increase in the complexity of the machine assembly and cost of this induction machine.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 14 August 2007

Jerzy Kołowrotkiewicz, Mariusz Barański, Wojciech Szelęg and Lech Długiewicz

The paper aims to elaborate the method and algorithm of analysis of induction motor working in cryogenic temperature.

Abstract

Purpose

The paper aims to elaborate the method and algorithm of analysis of induction motor working in cryogenic temperature.

Design/methodology/approach

This paper presents the design and investigation of performance characteristics of three‐phase high voltage squirrel‐cage submerged motor. The motor is intended to work at cryogenic temperature −161°C in liquefied natural gas (LNG). The time‐stepping finite element method of transients analysis in induction motor working in cryogenic temperature has been presented. The nonlinearity of the magnetic circuit, the movement of the rotor and skewed slots have been taken into account.

Findings

The study finds that presented method and elaborated software are used to determine the steady state and dynamic performance of the high voltage squirrel‐cage submerged motor. The results of simulations and measurements of constructed model motor have been presented.

Research limitations/implications

The problem has been considered as the 2D one. In order to take into account the skewed slots of the rotor the multi‐slice finite element method has been used.

Practical implications

Investigation presented in the paper has been performed in order to study the influence of the temperature on motor characteristics and to verify design calculations. No‐load current, starting torque and short‐circuit current during short‐circuit test, obtained on the basis of measurements and received from calculations, are in good concordance.

Originality/value

The paper proposes a method to determine the steady state and dynamic performance of the high voltage squirrel‐cage submerged motor working in cryogenic temperature.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 October 2004

Alvaro Valencia and Williams Calderón

Flow structure and convective heat transfer in a plane channel with in‐line mounted rectangular bars have been investigated for different bar sizes in the Reynolds number range…

Abstract

Flow structure and convective heat transfer in a plane channel with in‐line mounted rectangular bars have been investigated for different bar sizes in the Reynolds number range corresponding to steady laminar flow to unsteady transitional flow. Numerical results are reported for the thermal entrance region with six in‐line mounted bars and for the case with spatially periodic mounted bars. Data for heat transfer and pressure drop are presented for 100≤Re≤1,000 and bar heights 0.24≤d/H≤0.48. The unsteady Navier‐Stokes equations and the energy equation have been solved by a finite‐volume code with staggered grids combined with SIMPLEC pressure correction. Flow and heat transfer characteristics in the different rows are strongly dependent on Re and d/H. The flow structure and temperature field around the sixth row are compared qualitatively well with those calculated with periodic boundary conditions, however, the comparison of mean Nusselt number and friction factor shows differences for high Reynolds numbers.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 14 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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