Induction motors are presently the most widespread kind of electric machinery used in industrial and vehicle applications. In the engineering practice, it frequently happens that designers or final users have to roughly estimate the size, weight and some basic performance data of an induction motor based on few specification requirements such as its rated speed and power. This paper describes a heuristic approach which can help make a first-attempt dimensioning in an approximate but reliable way. The method uses homothety as the theoretical basis and derives practical laws by identifying homothetic law parameters through the statistical analysis of a set of sample built machines. The results obtained are compared to those derived from classical books showing significant discrepancies which fully justify the adoption of more sophisticated heuristic models as those being presented.
