Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Attenuation of magnetic field components through an AC machine stator

Attenuation of magnetic field components through an AC machine stator Purpose – Non‐intrusive magnetic measurements in AC machines are possible with small flat coils stuck on the external surface of the housing of a running motor. The aim of the paper consists in determining transmission coefficients able to give a direct relationship between the weak external flux density and the airgap one. Design/methodology/approach – An experimental approach shows that the decoupling principle can be applied. Transmission coefficients are determined separately for the stator yoke, the motor housing and the external air. Findings – For low frequencies and a housing made of steel, eddy current can be neglected. The transmission coefficient depends strongly of the mode (number of poles) of the rotating field. Conversely, for higher harmonic ranks, the additional attenuation caused by eddy currents in the housing does not practically depend on the mode but is strongly dependant on the frequency. Research limitations/implications – The transmission coefficients are determined considering a 2D electromagnetic model and several simplifying hypothesis. Experiments prove the validity of the proposed approach up to 550 Hz. Practical implications – Up to now, many fault detection systems are based on the presence of additional harmonics in the external magnetic field spectrum. With the knowledge of simple transmission coefficients, an analysis of the variation of the magnitude of critical spectrum lines is now possible for a more precise fault detection in AC machines. Originality/value – To the authors' knowledge, the only alternative way for the interpretation of external field measurements consist in using a numerical method with a full model of the machine which takes a lot of computation time. The proposed transmission coefficients provide a faster method valid for most of the interesting spectrum lines. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering Emerald Publishing

Loading next page...
 
/lp/emerald-publishing/attenuation-of-magnetic-field-components-through-an-ac-machine-stator-Ft1SGyWljL

References (16)

Publisher
Emerald Publishing
Copyright
Copyright © 2008 Emerald Group Publishing Limited. All rights reserved.
ISSN
0332-1649
DOI
10.1108/03321640810878144
Publisher site
See Article on Publisher Site

Abstract

Purpose – Non‐intrusive magnetic measurements in AC machines are possible with small flat coils stuck on the external surface of the housing of a running motor. The aim of the paper consists in determining transmission coefficients able to give a direct relationship between the weak external flux density and the airgap one. Design/methodology/approach – An experimental approach shows that the decoupling principle can be applied. Transmission coefficients are determined separately for the stator yoke, the motor housing and the external air. Findings – For low frequencies and a housing made of steel, eddy current can be neglected. The transmission coefficient depends strongly of the mode (number of poles) of the rotating field. Conversely, for higher harmonic ranks, the additional attenuation caused by eddy currents in the housing does not practically depend on the mode but is strongly dependant on the frequency. Research limitations/implications – The transmission coefficients are determined considering a 2D electromagnetic model and several simplifying hypothesis. Experiments prove the validity of the proposed approach up to 550 Hz. Practical implications – Up to now, many fault detection systems are based on the presence of additional harmonics in the external magnetic field spectrum. With the knowledge of simple transmission coefficients, an analysis of the variation of the magnitude of critical spectrum lines is now possible for a more precise fault detection in AC machines. Originality/value – To the authors' knowledge, the only alternative way for the interpretation of external field measurements consist in using a numerical method with a full model of the machine which takes a lot of computation time. The proposed transmission coefficients provide a faster method valid for most of the interesting spectrum lines.

Journal

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic EngineeringEmerald Publishing

Published: Jul 11, 2008

Keywords: Measurement; Electric machines; Magnetism

There are no references for this article.