The Effect of Alternating Current Frequency on the Mass and Size Parameters of Transformers and Small-Power Induction Motors

Resumo

The ac frequencies of 50 and 60 Hz, which are accepted in world practice, have not been substantiated technically and economically as the best for all components of the electric power systems, electrical installations and electrical equipment. Moreover, theory and practice show that, for many electromagnetic and electromechanical devices used in aircraft and water vessels, in construction and road construction machinery with motorwheels, in the agriculture industry, in the timber and timber-processing industry, and in other economic and infrastructural spheres, ac overfrequencies (f > 60 Hz) are preferable. Meanwhile, on the one hand, the wide range of frequencies (100–500 Hz) is considered the optimum, and, on the other hand, the cumbersome analytical expressions for substantiation and calculation of specific machines equipped with the electromagnetic devices, normally including transformers and the widely used inductions motors, are proposed. Simplified procedures for the analysis of the effect of ac frequency on the mass and size parameters of transformers and low-power induction motors are proposed in this article. They allow narrowing the optimum frequency range down to 200–400 Hz and obtaining acceptable results from engineering calculations of this effect.