The study and analysis of processes of winding defects precipitation in electric machines of printing complexes

In recent years, higher demands for quality and reliability of electrical machines are developed and approved. An important role in solving the increase in reliability is given to insulation materials. Nevertheless, the processes of cracking and isolation failures during heat aging are to be fully researched, physical and chemical interactions of impregnating materials in the construction with wire enamel are not shown. As a result of interaction an electrical strength of interturn insulation may increase or decrease. Distribution of internal stresses in interturn isolation has a complex character and may depend on the random position of wires in a groove, the groove filling factor, etc. The aim of this work is to study the probability of cracking of wire penetrating parameter and the groove filling factor and also of wire diameter and number of turns in the coil. Based on the results of the study it is found that the probability of cracking of polymer insulation is reduced more than 5 times with the increase of wire geometric parameters from 1 to 1.4, and the factor of groove filling by enameled wire has virtually no effect on the probability of cracking of polymer medium. Mathematical model of interturn isolation cracking allows to evaluate the impact of cracking on physical and mechanical parameters of impregnating materials and structural factors, such as enameled wire diameter, groove filling factor, the number of wires in the coil