High frequency electromagnetic emissions of cylindrical laminated cores

Abstract

Purpose

This paper aims to propose a high‐frequency (HF) model able to compute the flux density in the vicinity of the laminated stator core of an AC machine.

Design/methodology/approach

Experiments form the main approach. Analytical results previously obtained with a simplified rectangular laminated structure are confirmed with a standard cylindrical magnetic core.

Findings

Three frequency domains are defined, depending on the skin depth relative to the thickness of the magnetic sheets. A methodological approach is proposed for each domain. For higher frequencies, the magnetic core can be considered as transparent for external field computation.

Research limitations/implications

The HF model is valid for skin depths much lower than the thickness of the magnetic sheets.

Practical implications

The proposed HF model provides a link between the weak field measured in the natural void existing between the stator core and the housing of large electrical machines. With such a link, it is possible to develop a new monitoring system able to detect and to localize the partial discharges in the stator winding of a large machine.

Originality/value

The low‐frequency limit of the model has been measured. It corresponds to a ratio of 1/40 between the skin depth and the magnetic sheet thickness. Therefore this model offers a new perspective for maintenance applications.

Citation

Duchesne, S., Lecointe, J., Périsse, F. and Napieralska‐Juszczak, E. (2008), "High frequency electromagnetic emissions of cylindrical laminated cores", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 27 No. 4, pp. 735-743. https://doi.org/10.1108/03321640810878135