Evaluating FEMM for Torque Analysis in Induction Machines: A Complementary Tool for SMEs

Abstract:
This paper discusses the challenges faced by small and medium-sized enterprises (SMEs) in electrical machine design, particularly the high costs of commercial software for electromagnetic analysis. Traditional analytical methods remain in use, but advances in material data and standardized type testing demand greater accuracy. This study benchmarks the free software FEMM (Finite Element Method Magnetics) as a cost-effective alternative. Its performance is evaluated for a 420W induction machine, with results compared against measurements and the company’s analytical method. Three torque calculation approaches are assessed: FEMM’s built-in torque function, a regression-based equivalent-circuit method, and the flux–current cross-product method. The built-in function shows good agreement with measurements, the regression method enables parameter identification, and the cross-product method yields similar accuracy while allowing harmonic analysis of the flux linkage. The results show that FEMM, combined with MATLAB, provides a viable low-cost workflow for preliminary design and educational use, provided its two-dimensional limitations are considered.