The study investigates the influence of the lamination geometry on the building factor of stator magnetic cores, quantifying by experiments the influence of the punching and the annealing process. The research and the experimental activity are focused on small-fractional-power synchronous reluctance motors, where the effect of the punching process is expected to be very impacting, not only for the stator iron losses increase, but also because the current magnetizing component is dominant in the total input current. However, the obtained results are particularly interesting for any fractional and low power electric machines, whose cores are built with punched or laser-cut laminations.

Electrospinning is a very interesting method that allows the fabrication of continuous fibers with diameters down to a few nanometers. This paper presents an overview of electrospinning systems as well as their comparison using proposed three-dimensional parameterized numerical models. The presented solutions allow an analysis of the electric field distribution.

The paper deals with the accurate flux map modeling of synchronous reluctance motors, using finite element analyses. Non-negligible discrepancies were initially observed by comparing 2D-FEM simulation results with measured flux maps of real machines. Conversely, the 3D FEM-based flux mapping offers more accurate estimation of the aforementioned flux linkage characteristics, and gives evidence of the 3D end effects being also a function of the relative position between the magneto-motive force waveforms of the rotor and the stator. The paper investigates such three-dimensional end effects for different rotor geometries and winding structures, utilizing 2D and 3D FEM analysis in comparison to experimental data. The paper confirms that the 3D effects are non-negligible both in concentrated and distributed-winding machines. A simple mathematical approach is proposed for the concentrated-winding machine, capable of off-line correction of the 2D FEM flux maps. The proposed closed-form equation is validated through 3D FEM and experiments.

This paper deals with the results of measurements, calculations, and computer simulations, leading to the determination of the stator core's building factor (BF) of the fractional power synchronous reluctance motor (350 W). In the process of calculation, the authors indicated the part of the BF factor resulting from the punching process, the geometry of the stator core, and the fabrication process carried out during manufacture of the core. The obtained results indicate that for the analyzed core, the BF factor component resulting from the punching is greater than the sum of the components coming from clamping and pressing the core into the housing. The factor component dependent on geometry is less important. The data necessary for the finite-element method modeling were obtained from the modified SST system, whose idea has been described in detail.

The paper deals with experimentally-based comparative analyses aimed at quantifying the annealing process effects on the magnetic core properties of small synchronous reluctance motors. For this purpose, ‘ad hoc’ prototypes have been produced by adapting two twin normal-production, 120 W, line-start synchronous machines and, for one of them, the stator and rotor cores have been annealed. As an attempt to discriminate the iron losses reduction due to the annealing, no-load tests with sinusoidal supply have been performed, while the magnetizing currents and the related torque capability of the machines is also approached measuring their flux mappings (magnetic models). Finally, the performed tests have been replicated using 2D finite element method models that include the damaged material zones in the lamination edges due to the punching. Very good agreements between measurement and simulation results have been obtained.

The paper describes calculations method of heat transfer coefficient for finned induction motor housing and equivalent thermal conductivity for air zones inside this housing. The method is based on Computational Fluid Dynamics(CFD). In addition, the results of thermal calculations to verify calculated values of coefficient are presented.