JPS5728318A - Manufacture of insulated coil - Google Patents

Abstract

PURPOSE:To obtain a highly reliable insulated coil by a mehtod wherein a conductor is composed of an insulation treated strand, wound about by an earth dielectric layer, while the strand is divided into two groups at the time of impregnation and the extent of impregnation is detected by the change of a dielectric characteristic between the groups. CONSTITUTION:A strand S of copper wire S1 coated with glass S2 is bundled to be divided into a group 8 and a group 9. The strands in the groups are arranged zigzag to each other. The strands of both fellow groups 8 and 9 are mutually connected at the ends thereof through a lead wire 6 to be connected with a measuring apparatus for measuring a temporary change of a dielectric characteristic such as electrostatic capacity between both groups 8 and 9. When a coil is thus impregnated with the resin 4 in a tank 5, the capacity between the groups 8 and 9 is extremely big and when the resin is impregnated among the strands the capacity is greatly increased to make the detection easy. And until the start of impregnation the capacity does not change while being saturated with finished impregnation. Thereby the impregnation is finished in a proper time to obtain a highly reliable insulated coil.