METHOD OF CONTROL AND REPAIR OF WIRE INSULATION Russian patent published in 2018 - IPC G01R31/08 H02G1/16 

FIELD: electricity.

SUBSTANCE: method of control and repair of winding wire insulation involves detecting a defect in the insulation of a moving wire by control devices and measuring its extent. Further, when passing a defective area under the enamel application unit, an electrostatically charged enamelling lacquer is applied to the detected defect. For high-strength heat-resistant enamelled winding wires PETV, the enamel insulation of which is made of PE-939 lacquer, a composition for electrostatic coating of film binder on the defective area, for which the liquid PE-939 lacquer of B grade is added with dioxane and the surface tension coefficient is controlled. Then, when the specified coefficient reaches the values (4÷5)⋅10⁶ N/cm, the dilution of the lacquer with dioxane is terminated and 1% ammonia is added to the resulting composition, while measuring the specific resistance of the mixture obtained. Addition of ammonia is stopped when the composition reaches the value of the volume resistivity lying in the range of (10^-5÷10^-6) Om^-1 m^-1. Thereafter, said mixture is electrostatically charged by passing it through a nozzle to which a negative high voltage potential pulse is applied in the range of (-2÷-4) kV, the duration of which is equal to the time of passing the defective area under the nozzle. After the application of the liquid enamel film to the defective area excess enamel is removed, then the defective area with the liquid enamel applied to it is subjected to baking and drying.

EFFECT: increasing the accuracy of detection of defective areas in the insulation of the wire and their extent with further repairs, improving the efficiency of repair.

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