Stress relieving member for encapsulated transformer windings

Claim 2

A winding assembly for electrical inductive apparatus, said winding assembly comprising high-voltage and low-voltage winding sections encapsulated in a resinous insulating material, each of said winding sections comprising a plurality of concentric turns of electrical conductor, a stress relieving member positioned between a first of said winding sections and the encapsulating resinous insulating material to permit relative movement therebetween, said stress relieving member comprising a first layer of electrical conducting foil disposed in contact with an outer turn of said first winding section, there being substantially no encapsulating material between said outer turn and said steess relieving member, said first layer of electrical conducting foil of said stress relieving member having first and second ends with said first end physically and electrically connected to said outer turn of said first winding, said first layer of foil having a height dimension substantially equal to the height dimension of said first winding sectIon, and said first layer of foil extending substantially along the entire circumference dimension of said first winding section.

Claim 3

The winding assembly of claim 1 wherein the first and second ends of the first layer of foil are eletrically insulated from each other.

Claim 4

The winding assembly of claim 2 wherein the second end of the first layer of foil is located at a position along the circumference of the first winding section that provides a gap between the first and second ends of the first layer of foil.

Claim 5

The winding assembly of claim 1 wherein the first end of the first layer of foil is electrically connected to the outer turn of the first winding section by a terminal member which crimps the outer turn and the first layer of foil together.

Claim 6

The winding assembly of claim 1 wherein the first winding section is wound with sheet type conducting materials.

Claim 7

The winding assembly of claim 1 wherein the stress relieving member comprises a second layer of electrical conducting foil disposed between the first layer of foil and the resinous insulating material, said second layer of foil having first and second ends with said first end electrically connected to the first end of the first layer of foil, said second layer of foil having a height dimension substantially equal to the height dimension of the first layer of foil, the second end of said second layer of foil being positioned substantially adjacent to the second end of the first layer of foil with an adhesive material disposed between the first layer of foil and the outer turn of the first winding section.

Claim 8

The winding assembly of claim 6 wherein the first and second layers of foil comprise a single foil sheet having a height dimension substantially equal to the height dimension of the first layer of foil, said single foil sheet being folded about an axis parallel to the height dimension of said single foil sheet.

Claim 9

The winding assembly of claim 6 wherein the first and second layers of foil comprise a single foil sheet having a height dimension substantially equal to twice the height dimension of the first layer of foil, said single foil sheet being folded about an axis perpendicular to the height dimension of said single foil sheet.

Claim 10

The winding assembly of claim 6 wherein the first and second layers of foil comprise a single foil sheet having a height dimension substantially equal to twice the height dimension of the first layer of foil, said single foil sheet being folded about two axes which are perpendicular to the height dimension of said single folded sheet.

Claim 11

The winding assembly of claim 6 wherein adhesive material is placed between the first and second layers of foil with openings between adhesive locations to provide means for gases to escape from between the layers of foil.

Claim 12

The winding assembly of claim 6 wherein the layers of foil include slots which provide means for gases to escape from between the layers of foil.

Claim 13

An encapsulated transformer winding assembly comprising an inner low-voltage winding section, an outer low-voltage winding section, a high-voltage winding section disposed between said inner and outer low-voltage winding sections, said outer low-voltage winding section being wound with an electrical conducting sheet material to form start and finish conductor-turns, said transformer winding assemly being encapsulated with a resinous material, a stress relieving member positioned in contact with the start conductor-turn of said outer low-voltage winding section and the encapsulating material, said stress relieving member permitting relative movement between said encapsulating material and said outer low-voltage winding section, there being substantially no encapsulating material between said start conductor turn and said stress relieving member, said stress relieving member comprising a layer of electrical conducting sheet material having first and second ends, said first end of said layer being physically and electrically connected to the start Conductor-turn by a terminal member, and said second end of said layer being positioned to provide a gap between the first and second ends of said sheet material.

Claim 14

An encapsulated transformer winding assembly comprising an inner low-voltage winding section, an outer low-voltage winding section, a high-voltage winding section disposed between said inner and outer low-voltage winding sections, said outer low-voltage winding section being wound with an electrical conducting sheet material to form start and finish conductor-turns, said transformer winding assemly being encapsulated with a resinous material, a stress relieving member positioned in contact with the start conductor-turn of said outer low-voltage winding section and the encapsulating material, said stress relieving member permitting relative movement between said encapsulating material and said outer low-voltage winding section, there being substantially no encapsulating material between said start conductor turn and said stress relieving member, said stress relieving member comprising a layer of electrical conducting sheet material having first and second ends, said first end of said layer being physically and electrically connected to the start Conductor-turn by a terminal member, and said second end of said layer being positioned to provide a gap between the first and second ends of said sheet material.