METHOD AND APPARATUS FOR MANUFACTURING A VARIABLE INSULATED HELICALLY WOUND ELECTRICAL COIL

摘要

A method and apparatus for manufacturing a variable insulated helically wound electrical coil is disclosed. Insulated rectangular wire is fed from a supply reel to a coating zone and within the coating zone liquid resin insulation is selectively applied to the wire so it has additional insulation only in those areas of the coil where the dielectric strength is needed. The insulated wire is fed through a curing station to allow curing of the additional insulation prior to winding the cured insulated wire into a coil. The cured insulated wire is wound into a coil of predetermined shape at a winding station whereby the portions of the wire having the additional insulatin are located in the areas of the coil where the greatest dielectric strength is needed. The timing of the resin application to the wire is coordinated with the winding of the coil so that the proper insulation thicknesses are achieved at the required locations in the coil. There is also disclosed a variably insulated helically wound high voltage electrical coil for a transformer wherein a variable thickness of cured synthetic resin insulation is applied to the turns in each layer of the coil so that the insulation increases in thickness from substantially zero at one end of the layer where layer-to-layer voltage stresses will be low and the required maximum thickness at the opposite end of the layer where voltage stresses will be high and this progression and insulation thickness is repeated on each adjacent layer of the coil.