Analysis of no-load force pulsations, and cogging torques in induction machines
Analysis of no-load force pulsations, and cogging torques in induction machines
An accurate method is given for the determination of no-load tooth-ripple force and flux pulsations produced by relative motion of the slotted stator and rotor. The relationship between the force pulsations and the defining air-gap dimensions is investigated. It is shown that a simple relationship exists between the tangential component of tooth-ripple forces and the main flux pulsations into the teeth. Results are presented in the form of graphs, and relatively simple equations for the basic force and flux quantities are derived and examined. Conclusions of practical values are drawn from the results obtained.When using the conformal transformation method to solveLaplacian fields it is sometimes necessary to numerically evaluate integrals containing singularities. Quadrature methods for performing this are reviewed, and a novel method is given for the numerical evaluation of the Cauchy principal values typically encountered.Cogging torques in induction motors with squirrel cage rotor scan be made negligibly small by a correct choice of design parameters. A method of analysis has been described previously by Binns for the determination of their magnitude and this method is used to show that simple rules can be derived for the effective elimination of the cogging tendency without recourse to slot skewing. It is demonstrated that the rules are not so restrictive that they cannot be applied to most machines in conjunction with other criteria for the choice of slot combinations.
University of Southampton
1977
Rowlands-Rees, Graeme
(1977)
Analysis of no-load force pulsations, and cogging torques in induction machines.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
An accurate method is given for the determination of no-load tooth-ripple force and flux pulsations produced by relative motion of the slotted stator and rotor. The relationship between the force pulsations and the defining air-gap dimensions is investigated. It is shown that a simple relationship exists between the tangential component of tooth-ripple forces and the main flux pulsations into the teeth. Results are presented in the form of graphs, and relatively simple equations for the basic force and flux quantities are derived and examined. Conclusions of practical values are drawn from the results obtained.When using the conformal transformation method to solveLaplacian fields it is sometimes necessary to numerically evaluate integrals containing singularities. Quadrature methods for performing this are reviewed, and a novel method is given for the numerical evaluation of the Cauchy principal values typically encountered.Cogging torques in induction motors with squirrel cage rotor scan be made negligibly small by a correct choice of design parameters. A method of analysis has been described previously by Binns for the determination of their magnitude and this method is used to show that simple rules can be derived for the effective elimination of the cogging tendency without recourse to slot skewing. It is demonstrated that the rules are not so restrictive that they cannot be applied to most machines in conjunction with other criteria for the choice of slot combinations.
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Published date: 1977
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Local EPrints ID: 458688
URI: http://eprints.soton.ac.uk/id/eprint/458688
PURE UUID: 80b78ecd-fc26-48b2-9cdd-04ffbeb59659
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Date deposited: 04 Jul 2022 16:54
Last modified: 04 Jul 2022 16:54
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Author:
Graeme Rowlands-Rees
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