Ogar V. Induction Motors Characteristics When Changing Steel Properties

The theses deal with the problem of advancing the steel estimation methods with taking into account magnetic system properties changing during induction motor characteristics investigation. The paper presents the analysis of existing techniques for IM iron loss determination. It has proved the necessity of the development of the technique for the iron loss estimation taking into account the magnetization curve nonlinearity. The IM equivalent circuit has been proposed with the additional e.m.f. of the magnetization loop. The circuit takes into account higher current harmonics characterizing the saturation duty. The paper presents the dependencies of the instantaneous power on the inductive element including nonlinearity and hysteresis. One of the IM characteristics describing the physical properties of the machine magnetic system is a nonlinear characteristic of the inductive element of the magnetization loop. So the proposed technique is based on the instantaneous voltage and current and parameters of the non-saturated equivalent circuit to determine the nonlinear characteristic of the inductive element of the magnetization loop, when there is no additional technical tool for testing. The instantaneous voltage and current are measured with the computer-based complex The effect of the magnetic system properties such as the magnetization curve nonlinearity and Eddy currents increasing on the induction motor characteristics has been investigated. To decrease the energy consumption, the corrected pattern for the frequency control has been proposed taking into account Eddy currents effect. The problem of the computer-based measuring and diagnostic complex design for the experimental determination of the IM iron loss and characteristics has been considered.