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Single-phase induction motor (SPIM) has been widely used in home appliances due to its simplicity, low cost, low noise and ruggedness. However, to produce a cost effective high efficiency SPIM is necessary to have a good knowledge and good control of process parameters. Dynamometer's results of motors made with different process parameters show that rotor cages are more sensitive to process variations than stators and that they can to worsen the motor efficiency and torque characteristics. The aim of this work is to evaluate some steps of rotor cage process, namely rotor laminates coating, aluminum die-cast methods and rotor annealing and to analyze the effect of such parameters on motor performance. Results obtained from tests with a 2-pole, 100 W, high-efficiency SPIM are presented.

Generator air gap non-uniformity causes an imbalance of magnetic forces that result in Unbalanced Magnetic Pull - UMP. This phenomenon can cause high vibrations on the rotor. The addition of equipotential connections leads to an increment of the circulating current among parallel circuits of the stator winding, decreasing the magnetomotive force of armature reaction. Since the forces of magnetic attraction are proportional to the square of the resulting air gap magnetic induction, a change in their values along the circumference of the rotor, with the help of equipotential connections, will reduce the UMP. This solution is economically advantageous and the machine stop time can be shortened.

Cogging torque is produced in a permanent magnet machine by magnetic attraction between the rotor permanent magnets and the stator teeth. It is an undesirable effect that contributes to torque ripple, vibration and noise of the machine. In this paper, the resultant cogging torque values are computed using a three-dimensional (3D) finite element analysis. For this, the rotor movement is modeled by means of the moving band technique in which a dynamic allocation of periodic or anti-periodic boundary conditions is performed. The 3D finite element method is the most accurate tool to carry out cogging torque. However, it does not easily allow a parametric study. For this reason, an analytical model was developed in order to predict the cogging torque. The tools are intended to be used for the study of transverse flux machines.