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Literature agrees that cutting may damage the electromagnetic properties of electrical steel sheets, notably along the cut edge. However, statements on the depth of the deterioration vary. An analysis of the various results presented would allow for a better consideration of the material degradation in the modeling of electromagnetic properties of the cut steel sheet in electric machines. To this aim, this paper analyzes and summarizes the deterioration depths presented in the literature. It not only provides an overview of the quantitative results, but discusses these in the context of the respective measurement method, since every technique used only provides an image of some of the aspects of the cut material affected by the cutting process. [ABSTRACT FROM AUTHOR]

The degrading effect of laser cutting on steel sheet material, and thus on the material's magnetic characteristics, is much less understood than that of mechanical cutting. Furthermore, the degrading influence on the magnetic properties is still difficult to determine. This paper focuses on the modeling of the degrading influence of laser cutting on the magnetic properties of electrical steel sheets. As the degradation depth and the degradation profile are still difficult to define, a method is needed, which takes the effect of laser cutting into account, but without the need of knowing the degradation profile exactly. This paper shows that a method that does not require any information on the physical phenomena that are introduced by the cutting process and that has already been verified for mechanically cut samples can also be applied to laser-cut samples, although the deterioration mechanisms and the resulting degradation profile and depths differ. Magnetic characteristics are identified for two different material zones and subsequently inserted into a finite-element model, which accounts for arbitrary geometries. The simulation results for the influence of laser cutting on the magnetic characteristics of the stator lamination stacks are verified by measurements, including three different materials and frequencies. [ABSTRACT FROM AUTHOR]

In this paper, the influence of three different cutting techniques, in particular mechanical cutting, solid-state laser cutting, and carbon dioxide laser cutting, on the quasi-static hysteresis curves of three different materials, commonly used with electric machines, is investigated. Furthermore, the additional effects of sample size and cutting direction are discussed. In contrast to the commonly used Epstein frame or ring sample tests, the examinations are carried out with a permeameter. A significantly different shape of the hysteresis curves of the small laser-cut in contrast to the mechanically cut samples is found. Furthermore, for some samples a point of intersection is observed above which the magnetic behavior of laser-cut samples is better than that of the mechanically cut samples. [ABSTRACT FROM PUBLISHER]

The cutting process has a substantial influence on the ferromagnetic material properties of electrical steel sheets. In this paper, the properties of the degraded and nondegraded zones result from data obtained by two Epstein frame measurements using sample strips of two different widths. The magnetic characteristics of the degraded and nondegraded material are inserted into a finite-element model, which accounts for arbitrary geometries. The simulation results for the influence of degradation on a stator lamination stack are verified by measurements at three different frequencies and two different materials. [ABSTRACT FROM AUTHOR]

Aiming to better understand and model the different loss mechanisms occurring within electric machines during operation, we present a method to consider the degradation of steel during manufacturing due to punching in finite-element modeling of electric machines. The approach introduces a certain number of boundary layers along the punched edges, with the relative permeability decreasing toward the edge. The method, its implementation, and two example applications are presented and supported with experimental results. [ABSTRACT FROM AUTHOR]