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Showing 3 results for Subject: Induction Machines

H. Shadfar, H. R. Izadfar,
Volume 16, Issue 1 (3-2020)

Single-phase induction motors have a wide range of domestic and industrial applications. These motors have a squirrel cage rotor and their stator usually has two windings: main and auxiliary. The use of auxiliary winding in the structure of single-phase induction motors creates two unbalance and asymmetric phases. This causes to increase the spatial harmonics of the field in the air gap, and also useless electromagnetic forces. The purpose of this paper is the reduction of the electromagnetic forces in single-phase induction motors, focusing on the effect of the stator winding distribution. For this purpose, two new and different winding distributions for the motors used in the water coolers will be provided. The produced electromagnetic forces in several conventional single-phase induction motors will be compared with new and conventional windings by means of numerical methods. Numerical analysis is performed by Maxwell software. The results of this analysis indicate improvements in the quality of the performance of these motors in the presence of the provided windings.

M. Ghaseminezhad, A. Doroudi, S. H. Hosseinian, A. Jalilian,
Volume 17, Issue 1 (3-2021)

Nowadays study of input voltage quality on induction motors behavior has become a controversial subject due to the wide application of these motors in the industry. The impact of grid voltage fluctuations on the performance of induction motors can be included in this area. The majority of papers devoted to the influence of voltage fluctuations on the induction motors are focusing only on the solving of d-q state equations or steady-state equivalent circuit analysis. In this paper, a new approach to this issue is investigated by field analysis which studies the effects of voltage fluctuations on the magnetic fluxes of induction motors. New analytical expressions to approximate the airgap flux density and the torque under-voltage fluctuation conditions are presented. These characteristics are also calculated directly by the finite-element method considering the magnetic saturation and the harmonic fields. Finally, experimental results on a typical induction motor are employed to validate the accuracy of analytical and simulation results.

F. Rezaee-Alam, B. Rezaeealam, S. M. M. Moosavi,
Volume 17, Issue 3 (9-2021)

Poor modeling of air-gap is the main defect of conventional magnetic equivalent circuit (CMEC) model for performance analysis of electric machines. This paper presents an improved magnetic equivalent circuit (IMEC) which considers all components of air-gap permeance such as the mutual permeances between stator and rotor teeth, and the leakage permeances between adjacent stator teeth and adjacent rotor teeth in the air-gap. Since the conformal mapping (CM) method can accurately take into account the air-gap region, IMEC gets help from the CM method for calculating the air-gap permeance components. Therefore, the obtained model is a hybrid analytical model, which can accurately take into account the magnetic saturation in iron parts by using the CMEC, and the real paths of fringing flux, leakage flux, and the main flux in the air-gap by using the CM method. For a typical wound rotor induction motor, the accuracy of the results obtained by IMEC is verified by comparing them with the corresponding results determined through CMEC, improved conformal mapping (ICM), finite element method (FEM), and the experiment results.

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© 2022 by the authors. Licensee IUST, Tehran, Iran. This is an open access journal distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.