Determination of components of losses in the steel of the magnetic circuit of electric machines

Abstract

The division of total losses in electrical steel of the magnetic circuit of electric machines into three components is considered: hysteresis, classical eddy current and anomalous eddy current. The solution to this technical problem will make it possible to effectively design and construct electrical machines with magnetic cores having low magnetic losses. At present, such a separation of losses is associated with time-consuming measurements on special equipment and is performed with large errors. Each of these components depends differently on the magnetization frequency and temperature, and these dependences are known. Based on this, the paper proposes two methods for determining losses in steel – the method of three frequencies and the method of three temperatures. In order to fi nd three unknown quantities, three no-load experiments are proposed, carried out at three frequencies or at three temperatures of electric machine cores. Using the results of measurements of active powers spent on core heating, expressions of hysteresis, eddy-current classic and eddy-current anomalous losses are obtained. The results of the experiments carried out by the method of three frequencies and the method of three temperatures agree well with each other, which confi rms the adequacy of the methods and the possibility of their application in practice. The article analyzes the advantages and diffi culties of implementing each method. The methods can be applied to effectively minimize losses in the steel of electrical machines.