Analysis of the Methods for Determining Losses in the Transformer Magnetic Core

To effectively minimize magnetic losses and increase the efficiency of machines, particularly transformers, exact separation of total losses in the magnetic cores of electrical appliances into hysteresis and eddy current is required. To address this issue, the author proposes three variants of the wattmeter method, based on different dependences of eddy current and hysteresis losses on the magnetization reversal frequency, magnetic flux, and temperature, referring to the methods of two frequencies, two densities, and two temperatures. Two experiments were performed for each of the three methods under different conditions. In no-load experiments at two frequencies, at two magnetic flux densities, and two temperatures of the magnetic core, the active powers spent on heating the core were measured, and expressions for the powers of hysteresis and eddy current losses were obtained. The experimental results obtained using different methods are consistent with each other. The advantages and difficulties of each method are analyzed. The combination of methods determines the degree of density index for the magnetic flux in the hysteresis loss power expression (Steinmetz factor) in a particular transformer.