Тестирование гипотезы о зависимости массы электрических машин от мощности и частоты вращения

Abstract

The hypothesis stating that the mass of any rotating electric machine is proportional to its power capacity taken to a power of 0.75 and is inversely proportional to the square root of its rotation frequency is tested. The testing is carried out on the material of permanent magnet synchronous machines. The infl uence of such factors as voltage, shape of active parts, cooling, effi ciency level, overloads, presence of supporting structures, power supply frequency, and number of poles is studied. The hypothesis is tested by predicting the mass of machines in the widest possible range of power capacities (from 0.03 W to 36 MW) and rotation frequencies (from 2 to 500 000 rpm). The accuracy of the preliminary estimate of the machine mass within about 50% can be considered acceptable, given that the masses of the machines being estimated range from less than a gram to more than 100 t. Based on the study results, the formulation of a new law of electromechanics is proposed, which describes how the machine mass is predetermined in terms of its power capacity and rotation frequency. The ratio of machine power capacity taken to a power of 0.75 to the square root of its rotation frequency is to some extent similar to the “gravity” which the designers try to overcome working on weakening the eff ect of the above-mentioned infl uencing factors.