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The paper presents the use of the two-dimensional finite element method for modeling the three-phase squirrel-cage induction motor by using circuit coupled method. In order to analyze the machine performances, the voltage source is considered. The Ansys magnetic analysis software is used for calculating the magnetic field of an induction motor havi...
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A flat double-stator linear induction machine (DSLIM) with short cage mover is designed for high thrust force at moderate speed ≤ 5 m/s. The performance and motor parameters are determined on the basis of a 2D time-transient simulation with the finite element (FE) software Maxwell 2015. Design guidelines and transformation rules for space vector th...
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Citations
... f usb = f 1 (1 + 2s)Hz (21) Otherwise, the side-band frequencies (f sb ) around the higher-order slot harmonics can be obtained as [35]: ...
The requisite of Direct-on-line (DOL) starting for various applications in underground mines subjects the rotor bars of heavy-duty Squirrel Cage Induction Motors (SCIMs) to severe stresses, resulting in sustained fault in the rotor bars, unlike the applications where mostly reduced voltage starting is preferred. Furthermore, SCIMs working in underground mines are also affected by unforeseen frequency fluctuations. Hence, the paper proposes a Discrete Wavelet Transform (DWT)-based broken rotor bar detection scheme using stator current analysis of SCIM when subjected to frequency regulation (±4% of 50 Hz supply) in steady-state, as prevalent in underground mines. In this regard, the level-seven detailed coefficient obtained by DWT-based multi-resolution analysis of stator current corresponding to the healthy rotor is compared with that of the faulty rotor to extract necessary features to identify the fault. Further implementation of the proposed scheme is done using Artificial Neural Network (ANN)-based pattern recognition techniques wherein both feed-forward backdrops and cascaded forward backdrop type ANNs have been used for fault pinpointing based on the feature extraction results obtained from DWT. The scheme is developed and analysed in MATLAB/Simulink using 5.5 kW, 415 V, 50 Hz SCIM, which is further validated using LabVIEW-based real-time implementation.
... Generally the induction motor is excited by an external voltage source, from many models based on finite elements method, only the Circuit-Coupled Finite Element Method (Circuit-Coupled FEM) can close this reality, here the external electric circuit which contains the three voltage sources is coupled to the finite element domain which contains the magnetic circuit of the electric machine [5]- [6]- [7]. In table 1, specifications of the studied induction motor. ...
It is well known that the number of broken bars and varying load affect on the amplitudes of specific harmonic components in the process analysis of induction motors under broken rotor bars. The location of broken bars is an important factor which affects the diagnosis of the broken bars defect. In this paper the simulation is determinate for different cases for distribution of broken bars under induction motor pole in order to show the impact of broken bars location upon the amplitude of harmonic fault. The simulation results are obtained by using time stepping finite elements (TSFE) method. The geometrical characteristics of motor, the effects of slotting and the magnetic saturation of lamination core are included in induction motor model.
... Several authors head to the application of this technique for studying and analyzing eccentricity fault in induction motors [10], for them the assumption that currents and fluxes are sinusoidal varying restrict the solution if information such as stator current harmonics and torque pulsation are required, the alternative would be the full timestepping. Several papers have been used TSFE method to diagnose different faults in induction motors, most of these papers are focused on the diagnosis of broken rotor bar [25]- [26][27][28], in case of eccentricity analysis [10,29,30], in case of stator winding turn fault [31]. ...
... Generally the induction motor is excited by an external voltage source, from many models based on finite elements method, only the Circuit-Coupled Finite Element Method (Circuit-Coupled FEM) can close this reality, here the external electric circuit which contains the three voltage sources is coupled to the finite element domain which contains the magnetic circuit of the electric machine ( fig. 2) [32]- [28]. In table 1, specifications of the studied induction motor. ...
Unfortunately, motor current signature analysis (MCSA) cannot detect the small degrees of the purely static eccentricity (SE) defects, while the air-gap magnetic flux signature analysis (FSA) is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE) method. In order to show the impact of magnetic saturation upon the diagnosis of SE fault, the analysis is carried out for saturated induction motors. The index signatures of static eccentricity fault around fundamental and PSHs are detected successfully for saturated motor.
... Several authors head to the application of this technique for studying and analyzing eccentricity fault in induction motors [10], for them the assumption that currents and fluxes are sinusoidal varying restrict the solution if information such as stator current harmonics and torque pulsation are required, the alternative would be the full timestepping . Several papers have been used TSFE method to diagnose different faults in induction motors, most of these papers are focused on the diagnosis of broken rotor bar [25]- [26] [27] [28], in case of eccentricity analysis [10] [29] [30], in case of stator winding turn fault [31]. N. Halem et al. ...
Unfortunately, motor current signature analysis (MCSA) cannot detect the small degrees of the purely static eccentricity (SE) defects, while the air-gap magnetic flux signature analysis (FSA) is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE) method. In order to show the impact of magnetic saturation upon the diagnosis of SE fault, the analysis is carried out for saturated induction motors. The index signatures of static eccentricity fault around fundamental and PSHs are detected successfully for saturated motor.
A lot of African countries are underdeveloped owing to the lack of good education. In most African countries the poor economic health is responsible for the lack of proper infrastructure in the education sector. Therefore, the need for alternative means to educate the future generation arises. In Engineering a lot of laboratory work and apparatus are required, whereas only a few Universities can afford this. In Electrical Engineering for instance,” electrical machines” is a very vital topic that requires a lot of laboratory work. The analysis of induction machines is very expensive to experiment on in the lab, and this machine is the most widely used in the industry. This educational gap means that graduates are underequipped and unable to perform optimally in the industry without rigorous training exercise. This study investigates the use of a virtual laboratory (LabVIEW) to model and analyse induction motors with the aim of achieving results that closely conform to the standard characteristics of induction motors. The results obtained confirm that the use of virtual laboratories should be encouraged where finance is a problem as accurate results were obtained from the study.
Static eccentricity produces low frequency air gap flux components, however they can be observed in stator current spectrum only under mixed eccentricity, and for high degrees of rotor shifting. Unlike motor current signature analysis, the air-gap magnetic flux signature analysis allows to detect small degree of purely static eccentricity. The simulation results are obtained by using time stepping finite elements method. In order to indicate the influence of the magnetic saturation upon the analysis of the faulty induction motor, two constant and non-liner permeability; are included in this paper. It is shown that the fault index amplitudes of obtained signals from the constant permeability are larger than that of the real case. In this paper the amplitudes of characteristic frequency components
$ f_{ecc} = \left| {f_{s} \pm k{\kern 1pt} f_{r} } \right| $
f
ecc
=
|
f
s
±
k
f
r
|
with low degrees of purely static eccentricity fault are detected using air-gap magnetic flux signature analysis. Moreover, new index signatures are detected around the third time harmonics in air-gap magnetic flux density spectrum for saturated motor, those components are expressed by
$ f_{ecc} = mf_{s} \pm f_{r} $
f
ecc
=
mf
s
±
f
r
.
The objective of this work was to study thermogenesis during the process of Co-composting to assess the possibilities of thermal destruction of the germination capacity of weeds seeds. A regular monitoring of temperature has been achieved, using a probe thermometer, at nine locations of heap crafted. The outlines of temperature profiles allowed the identification of the four phases of the process, from a temperature monitoring, which is taken twice a day. The mid-monthly monitoring of temperature showed no significant differences for the first three dates of monitoring, whatever the depth and whatever time study. The bimonthly monitoring showed insignificant differences for the first three dates, whatever the depth of the heap and whatever the studied time. The last three dates showed insignificant differences for the time of recording, whereas for the depth, the results obtained were significant.
