In rolling bearing analysis Hertzian contact theory is used to compute local contact stiffness. This theory does not have a closed form analytical solution and requires numerical calculations to obtain results. Using approximations of elliptical functions and with a mathematical study of Hertzian results, an empirical explicit formulation is proposed in this paper and allows us to obtain the dimensions, the displacement, and the contact stress with at least 0.003% precision and it can be applied to a large range of ellipticity of the contact surface.

This papers deals with an original way to optimize the pre-designing of a switched reluctance motor (SRM). The analytic equations are treated to make the complete design depend only on two parameters. Particular attention is paid to high rotational speeds and the hypotheses they induce on the design. The hypothesis of a current control is assumed and the methodology tackles the design problem through the angle of the power electronics constraints.The specific problem set by the trapezoidal current shape is highlighted, as much as the direct constraints induced on the motor shape design. Mechanical and thermal limitations, modeled in function of the main material characteristics are deterministically taken into account. An optimization is finally performed, reducing the losses of the motor in terms of the mere lasting parameter.

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