Induction Motor Equivalent Circuit Including the Stray Load Losses in the Machine Power Balance

Boglietti, Aldo; Cavagnino, Andrea; Ferraris, Luca; Lazzari, M.

doi:10.1109/tec.2008.921467

Cited by 72 publications

(32 citation statements)

References 13 publications

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“…Because of the complex nature of the stray load losses, it is difficult where to locate the resistance R ad to quantify these losses more appropriately. The models in Figure evaluate the stray load losses according to rotor current , whereas those in Figure evaluate these losses on the basis of stator current . Considering the different effects included in these losses (e.g., additional losses on the stator windings), R ad would seem better placed in the stator.…”

Section: Proposed Equivalent Circuitsmentioning

confidence: 99%

Estimation of equivalent circuits for induction motors in steady state including mechanical and stray load losses

Torrent

2011

Int Trans Elec Energy Syst

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SUMMARY This paper presents equivalent circuits for analysing induction motors, including parameters that evaluate the mechanical losses and additional load losses, with the objective of achieving a power balance with all losses included in the equivalent circuit parameters. The different options of the circuits are presented, including two resistors that evaluate the losses with three commonly used models: single‐cage, double‐cage and slip‐dependent rotor parameters. Using nonlinear programming techniques, the equivalent circuit parameters were calculated in the different models from rated motor specifications on three induction motors (0.75, 1.5 and 5.5 kW). These motors were tested according to Standard IEC 60034‐2‐1 to compare the mechanical and additional load losses obtained in the proposed equivalent circuits analysis to those obtained according to standard tests. The equivalent circuit was calculated to the manufacturer's data for a four‐pole, 50‐Hz, class B, standard efficiency motors, with rated output power between 0.75 and 200 kW. Finally, a losses study was performed, and the separation of losses to the rated point was obtained for the studied motors. Copyright © 2011 John Wiley & Sons, Ltd.

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Section: Proposed Equivalent Circuitsmentioning

confidence: 99%

Estimation of equivalent circuits for induction motors in steady state including mechanical and stray load losses

Torrent

2011

Int Trans Elec Energy Syst

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“…It is important to remark that the rotor resistance value estimated by locked rotor tests takes into account not only the fundamental joule losses effect in the rotor bars, but also other secondary contributions, such as the losses in the cage short circuit rings, the additional losses due to induced currents by the airgap MMF spatial harmonic, and so on [11]. The obtained results seem to confirm that for the selected machine size these secondary contributions play a marginal role in the skin effect problem.…”

Section: Elm Experimental Validationmentioning

confidence: 99%

Skin effect experimental validations of induction motor squirrel cage parameters

Boglietti

Cavagnino

Ferraris

et al. 2008

2008 18th International Conference on Electrical Machines

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The paper deals with the experimental validations of the corrective coefficient used to take into account the skin effect in the equivalent circuit rotor resistance of induction motors with squirrel cages. Locked rotor tests have been performed at several supply frequencies on different induction motors; the collected experimental data have been used to validate the rotor parameters analytical estimation obtained by means a numerical procedure previously proposed by the authors. The reported comparison between experimental and calculated skin effect corrective coefficients shows that the adopted model allows to get satisfactory results in terms of accuracy, taking into account the objective difficulties to estimate the rotor parameters from the experimental tests.Keywords: induction motors, skin effect, and squirrel cage.978-1-4244-1736-0/08/$25.00 ©2008 IEEE

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“…Another useful technique is to change the stator winding [18][19][20][21][22], such as Y-∆ hybrid windings [18][19][20], concentric single-double layer windings [21] or adjust the parameters of single layer and double layer windings [22], to increase motors efficiency. Therefore, techniques for changing the type of stator windings and the air gap length are investigated in this paper.Many calculation methods have been developed to predict the running performance of induction motors [2,21,[23][24][25][26][27][28]. The steady-state performance of induction motors, including losses distribution, can be obtained by improving algorithms in FEM [2,23-25], but this method usually need researchers to write their own FEM program, which may be too complex to realize by other researchers and manufacturers.…”

mentioning

confidence: 99%

“…The steady-state performance of induction motors, including losses distribution, can be obtained by improving algorithms in FEM [2,23-25], but this method usually need researchers to write their own FEM program, which may be too complex to realize by other researchers and manufacturers. The steady-state and transient-state of induction motors can be carried out through circuit models [2,21,[26][27][28]. Researchers have used FEM to determine the parameters of the equivalent circuit model which considers the impacts of stray losses and harmonic torques [26].…”

mentioning

confidence: 99%

“…Researchers have used FEM to determine the parameters of the equivalent circuit model which considers the impacts of stray losses and harmonic torques [26]. The equivalent circuit is able to calculate the stray load losses of induction motors through modifying its structure based on motor power balance [27]. Based on the manufacturer's data, the parameters of the equivalent circuit model are optimized to improve its precision of calculating starting and full-load performance [28].…”

mentioning

confidence: 99%

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A Hybrid Methodology for Analyzing the Performance of Induction Motors with Efficiency Improvement by Specific Commercial Measures

Lee

Kirtley

et al. 2019

Energies

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This paper presents a hybrid methodology to analyze the commercial measures of changing stator windings and adjusting air gap length to upgrade efficiency of typical three-phase direct-on-line induction motors with die-cast copper rotor (DCR). The calculation is carried out through combining the time-stepping and time-harmonic finite element analysis (FEA) and the circuit equivalent circuit model. Typical full-load performance of stator windings with different air gap lengths are computed by MATLAB invoking the 2D transient and eddy current field analysis in ANSYS/MAXWELL. Then, MATLAB scripts about post-processing of the FEA results are used to obtain the full-load running performance including the loss distribution and circulating current. The MATLAB scripts of circuit model built based on the FEA results is used to compare the overload and starting performance. After that, four stators with the four windings and three DCRs with different air gap of an 11 kW motor are fabricated and tested to validate the calculations. By comparing results from both calculations and measurements, it is shown that the factors of stator windings and air gap length can effectively improve the efficiency of the 11 kW DCR induction motor without the addition of extra materials. The motor with the 11/12 pitch Y-∆ series winding and 0.6 mm air gap has the best performance, in terms of efficiency, overloading capability and starting performance. Its efficiency can increase from 90% to the highest 92.35% by sole adjustment of stator winding and air gap length.Many technical measures have been investigated for improving the efficiency of induction motors. The higher efficiency can usually be achieved by increasing the active materials, such as increasing the stack length [5,6], in induction motors. Another measure of upgrading materials such as premium electrical grade lamination steel is used for decreasing core losses and Ohmic losses [6][7][8].The efficiency can also be improved by enhancing the performance of cooling and bearing systems to reduce the mechanical losses [7] and improving cooling performance to make Ohmic losses less significant [9]. These methods either rise the raw material cost or increase manufacturing complexity. Although geometry optimization techniques [10][11][12][13][14][15][16] can be used to increase the efficiency of induction motors without increasing the active materials, this technique ends up producing a different design from the original one. Consequently, a new stator and rotor punching mold is required and additional cost results. It can be seen that in practice these measures can only be used to design a new motor, therefore many manufacturers have paid more attention to ways of increasing the efficiency of their induction motors with the least cost. That means the techniques should change construction or parameters of the existing motors as little as possible. Die-cast copper rotor (DCR) technology that involves the development of heated nickel-base alloy dies presents a potential route to design hi...

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Induction Motor Equivalent Circuit Including the Stray Load Losses in the Machine Power Balance

Cited by 72 publications

References 13 publications

Estimation of equivalent circuits for induction motors in steady state including mechanical and stray load losses

Estimation of equivalent circuits for induction motors in steady state including mechanical and stray load losses

Skin effect experimental validations of induction motor squirrel cage parameters

A Hybrid Methodology for Analyzing the Performance of Induction Motors with Efficiency Improvement by Specific Commercial Measures

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