Dehtiarenko O. Improving the diagnostics of laminated stator cores of synchronous motors

The purpose of the paper consists in the theoretical and experimental sub-stantiation of the ways for improving the efficiency of application of local methods of diagnostics of stator laminated cores and taking into account the change of their properties when determining the current state of synchronous motors. The basic reasons of the change of properties of sheet steel and stator cores are considered in the paper, the assessment of the core condition influence on pa-rameters and characteristics of the repaired machines is given. The analysis of the existing ways of the control and diagnostics of cores is carried out. The possibilities of increase of efficiency of process of diagnostics at the re-search of the dynamic magnetic characteristics of cores by local variable magnetic reversal with the help of measuring inductor at the change of amplitude and fre-quency of supply voltage are theoretically proved. The experimental verification of the basic points of the proposed way of di-agnostics is executed; its results have confirmed expediency of modulation of the supply voltage during testing the core. On the basis of experimental data the com-plete set of independent diagnostic parameters describing the change of electrical and magnetic properties of a core and being sensitive to presence of damages is de-termined. The results of the experimental research of the efficiency of contact and non-contact local testing tooth zone of cores of the electric machines are presented. The influence of the value of the air gap between measuring inductor and under the analyzed tooth surface on the sensitivity diagnostic parameter for existing type of the damages of cores is assessed. The generalized method of determining the current state of synchronous mo-tors, which takes into account the change of properties of stator laminated cores and other structural units in time and their interaction on the basis of neural net-work technologies and allows taking decisions on the need for repair operations is determined. The results of the diagnostics allow improving the quality of the repair of cores, taking into account the changes to the cores steel when calculating their pa-rameters and characteristics and determining their current condition thus improv-ing the efficiency and reliability of the post-repair operation.