Through defect development in interturn insulation of low voltage windings of electric machines

For the electric drives of lot production the problem of quality improving is the most actual. Their quality relates to their reliability and to the reliability of the mechanisms put in action by these drives. About 90% of the failures of electric drives results from the failure of the insulation system. Interturn insulation is the weakest part of this system. The failure of turn insulation is due to the presence of through defects in it, i.e. due to the defects in adhesive and enamel insulation of contiguous winding wires. The investigation of the change of physical and mechanical properties of the components of interturn insulation during heat ageing allows one to estimate the dynamics of this system stability change to cracks formation (i.e., the probability of the through defect formation). That in its turn allows one to conduct accurate estimate of the reliability of the whole system of insulation and the electric machine as a whole.