Method for manufacturing a molded transformer

Claim 1

A method of manufacturing a molded transformer, said method comprising the steps of: (a) forming each of at least two coils by: (i) winding on a frame a first insulated electrical wire in a coil and in layers with first insulating layers interposed between the adjacent layers of said first insulated electrical wire and with first insulating end members of high resin impregnability disposed on both ends of the respective layers of said first insulated electrical wire; (ii) winding on said first insulated electrical wire a first outer peripheral insulating layer on the outer surface of which a curing accelerator has previously been applied; (iii) winding on said first outer peripheral insulating layer a corrugated main insulating layer which form air ducts; (iv) winding on said corrugated main insulating layer an inner peripheral insulating layer on the inner surface of which a curing accelerator has previously been applied; (v) winding on said inner peripheral insulating layer a second insulated electrical wire in a coil and in layers with second insulating layers interposed between the adjacent layers of said second insulated electrical wire and with second insulating end members of high resin impregnability disposed on both ends of the respective layers of said second insulated electrical wire; (vi) winding on said second insulated electrical wire a second outer peripheral insulating layer on the outer surface of which a curing accelerator has previously been applied; and (vii) applying a dissolved curing accelerator on said first and second insulating end members on one end of each of said at least two coils; (b) forming a core-coil assembly by: (i) combining a one-turn, cut-type wound core with said at least two coils and (ii) putting spacers between said at least two coils and said one-turn, cut-type wound core, thereby making said at least two coils immovable relative to said one-turn, cut-type wound core; (c) drying said core-coil assembly in a drying furnace; (d) immersing said core-coil assembly with the insulating end members applied with said curing accelerator facing downwardly in a tank containing resin; (e) impregnating said core-coil assembly with the resin by first producing a vacuum in said tank, then pressurizing said tank to complete impregnation; (f) taking out said core-coil assembly when the resin on and close to said curing accelerator starts to gel due to the action of said curing accelerator and while the remaining portion of the resin is still in a liquid state; and (g) heating said core-coil assembly in a drying furnace, thereby setting the resin impregnated in said first and second insulating end members, in said first and second outer peripheral insulating layers, in said inner peripheral insulating layer, and on said one-turn, cut-type wound core.

Claim 2

A method of manufacturing a molded transformer, said method comprising the steps of: (a) forming each of at least two coils by: (i) winding on a frame a first insulated electrical wire in a coil and in layers with first insulating layers interposed between the adjacent layers of said first insulated electrical wire and with first insulating end members of high resin impregnability disposed on both ends of the respective layers of said first insulated electrical wire; (ii) winding on said first insulated electrical wire a first outer peripheral insulating layer on the outer surface of which a curing accelerator has previously been applied; (iii) winding on said first outer peripheral insulating layer a corrugated main insulating layer which form air ducts; (iv) winding on said corrugated main insulating layer an inner peripheral insulating layer on the inner surface of which a curing accelerator has previously been applied; (v) winding on said inner peripheral insulating layer a second insulated electrical wire in a coil and in layers with second insulating layers interposed between the adjacent layers of said second insulated electrical wire and with second insulating end members of high resin impregnability disposed on both ends of the respective layers of said second insulated electrical wire; (vi) winding on said second insulated electrical wire a second outer peripheral insulating layer on the outer surface of which a curing accelerator has previously been applied; and (vii) applying a dissolved curing accelerator on said first and second insulating end members on one end of each of said at least two coils; (b) forming a core-coil assembly by: (i) combining a one-turn, cut-type wound core with said at least two coils and (ii) putting spacers between said at least two coils and said one-turn, cut-type wound core, thereby making said at least two coils immovable relative to said one-turn, cut-type wound core; (c) drying said core-coil assembly in a drying furnace; (d) immersing said core-coil assembly with the insulating end members applied with said curing accelerator facing downwardly in a tank containing resin; (e) impregnating said core-coil assembly with the resin by first producing a vacuum in said tank, then pressurizing said tank to complete impregnation; (f) taking out said core-coil assembly when the resin on and close to said curing accelerator starts to gel due to the action of said curing accelerator and while the remaining portion of the resin is still in a liquid state; and (g) heating said core-coil assembly in a drying furnace, thereby setting the resin impregnated in said first and second insulating end members, in said first and second outer peripheral insulating layers, in said inner peripheral insulating layer, and on said one-turn, cut-type wound core.