Patent ID: 6221297
Filing Date: 2001-04-24
Classification: B29C,B29L,H01F,Y10T

Abstract:
A method of manufacturing a transformer coil encapsulated in casting resin utilizing a disposable casting mold comprising the steps of:forming an annular mandrel by applying to a mandrel shaft, a plurality of annular shaped support plates spaced on the shaft,forming a disposable inner mold by wrapping sheet metal over the annular shaped support plates during the winding setup process, to produce an integrated winding form/mandrel/inner mold, for use in the winding process,placing the integrated winding form/mandrel/inner mold in a winding machine,winding a coil around the inner mold while in the winding machine,forming an outer mold by wrapping a plurality of sheet metal layers over the finished coil and mechanically attaching the layers to the finished coil to hold the sheet metal in its starting position,spirally wrapping non-adhesive glass tape over the outer mold to secure it in position and completing the outer mold by banding the outer mold with banding strip at a plurality of spaced positions,removing the manufactured coil and mold assembly from the winding machine,up righting the coil and mold assembly and attaching a base thereto,providing a seal between the base and the coil and mold assembly to prevent epoxy leaks during the encapsulation process, andfilling the mold with epoxy to encapsulate the coil with casting resin.