Investigation of Linear Induction Motor Braking Modes by Spectral Method

Abstract

The article investigates the issues of electrical braking for induction motors the operation of which is based on the sliding magnetic field. It has been revealed that one of the most progressive analytical research methods of such type modes is considered the method of spectral magnetic fields analysis. To compile mathematical model there have been derived the main assumptions according to which all the measures of electric braking have to be investigated by means of the analysis of one dimensional magnetic field. The braking processes have been analysed in the motionless right – sided Descartes system of coordinates x, y, z. There have been presented the expressions of volumetric density of braking current which have been regarded the non – periodic functions of coordinate x. Besides that in cases of single – phase and capacitor braking these expressions are also regarded as the non – periodic functions of time. Therefore when compiling the mathematical model there have been applied Laplace and Fourier integral transformations. After having applied Fourier transformation there have been received the expressions of the spectra amplitudes of braking current volumetric density, under the condition that the number of excited zones in the inductor is even, uneven and fractional. The continuous spectra of amplitudes have been calculated by the software Mathcad 2001 Profesional. The results of the calculations indicate that the maximum amplitude density of dynamic braking current is obtained if the number of excited zones is uneven . Il.1, bibl. 7 (in English; summaries in English, Russian and Lithuanian).