Analytical formulation of the no-load magnetic field in IPM tubular machines with translator eccentricity

The design of electrical machines requires a suitable procedure in order to highlight the main machine parameters. Among them, the knowledge of the no load magnetic field as a function of the main geometry machine parameters helps designers in formulating optimal design choices. Inevitably, tubular machines are subject to eccentricity of the mover, therefore a non uniform distribution of the no load magnetic field in the air-gap arises. This yields attractive radial forces that must be taken into account in the choice of the bearings. This paper illustrates an analytical formulation of the no load magnetic field distribution in tubular IPM machines with translator eccentricity in order to facilitate the computation of the radial forces.