Abstract: A method of manufacturing a transformer coil encapsulated in casting resin utilizing a disposable casting mold where the disposable mold acts both as a winding mandrel and as an inner mold shell for resin encapsulation. The disposable casting mold may be oval shaped or circular shaped depending upon the desired shape of the coils to be encapsulated. The inner and outer mold shells are made from thin sheet metal and thus may be adjusted for the manufacture of a wide variety of sizes of oval shaped or circular shaped epoxy encapsulated coils.

Abstract: A method of manufacturing transformer windings embedded in casting resin is disclosed which utilizes an integrated winding mandrel for producing a non-standard oval shaped epoxy encapsulated low voltage coil for dry type distribution transformers. The method includes a process of winding a low voltage oval coil over a disposable mold which acts as both a winding mandrel and as an inner mold shell for epoxy encapsulation. Both the inner and outer molds are made of low cost sheet metal utilizing a “wrap and band” process The complete winding and molding processes can all be conducted on a standard winding machine.