GB910297A - Coil coating method - Google Patents

Abstract

910,297. Coil coating methods. CHRYSLER CORPORATION. May 3, 1961 [May 12, 1960], No. 16002/61. Class 35. A method of protectively coating electrical coils such as stator or rotor windings with an insulator comprises the steps of applying a source of electrical power to the coils to heat the same resistively and then bringing the heated coils into contact with powdered fusible and subsequently hardenable resin whereby the resin is picked up by the coils in sufficient quantity to fuse and subsequently set to form a continuous coating on the coils. Fig. 3 shows a slotted stator structure coated on the inner parts of its upper and lower surfaces with a plastic layer 14, the inner face 16 being left uncoated as shown in the sectional view of Fig. 2. The coils are heated by connecting them to a source of power and are then dipped into or sprayed with fluidized thermosetting or thermoplastic resin powder which sticks to the heated insulating covering for the wires of the coils. The powder may be of thermosetting epoxy resin or of thermoplastic cellulosic, vinyl, nylon, polyethylene or chlorinated-polyether resin. The material used is preferably an epoxy resin blended with dicyandiamide curing agent. In this case sufficient heat must be applied to the resin to cure it as well as to cause it to fuse to the surface of the windings. If insufficient heat is retained by the coils for this purpose a conventional curing oven may be used to provide the final step.