Air-core choke coil
First Claim
1. An axially symmetric air-core choke coil, comprising:
- at least one winding, said at least one winding having a plurality of helically wound, spaced apart, wire cable turns, said coil having an inner cylindrical periphery inside said coil and an outer periphery concentrically surrounding said inner periphery;
a plurality of axially extending, electrically non-conductive, strips, spaced circumferentially around said at least one winding, each strip including a plurality of folded sections, respective ones of said folded sections being fitted between respective adjacent turns, a plurality of air gaps being defined between said turns and said strips, said strips being arranged to permit radial and longitudinal air flow through said air gaps;
means for generating an axial air flow along said inner cylindrical periphery of said coil, said axial air flow being adapted to reduce the air pressure at said inner periphery to induce outside air to flow through said air gaps;
said means for producing an axial air flow comprises a screen, said screen being adapted to block air flow through the center of one axial end of said coil and to define an axial gap between the circumferential periphery of said screen and said at least one winding of said coil, whereby air entering said axial gap is accelerated to produce said reduced air pressure along said inner periphery of said coil; and
means for axially prestressing said at least one winding.
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Accused Products
Abstract
An axially symmetric air-core choke coil for high voltage applications. The coil includes a plurality of radially concentric, helically wound layers of windings. Non-insulated wire cable is used to produce each winding. Therefore, adjacent turns of each winding, as well as adjacent layers are spaced from one another. Separation between adjacent turns of each layer is provided through longitudinally extending, non-conductive, strips which are circumferentially spaced around the outer periphery of each winding layer. The strips are folded radially inward at the open spaces between turns. The layers are separated by a plurality of longitudinally extending non-conductive bars. The bars can be positioned to overlap the strips. Numerous air gaps are thereby defined between adjacent turns and adjacent layers which allow air to easily flow in a radial direction into the center of the air-core coil. A screen is provided at one axial end of the air-core coil to block the axial flow of air through the center of the air-core and to direct the axial air flow over the inner periphery of the air-core. This creates a Bernulli effect which reduces the air pressure within the air-core so that the radial air flow is substantially increased. Means are provided for axially compressing the windings of the coil to increase its mechanical strength to withstand disruptive forces which develop during short-circuit conditions.
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Citations
14 Claims
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1. An axially symmetric air-core choke coil, comprising:
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at least one winding, said at least one winding having a plurality of helically wound, spaced apart, wire cable turns, said coil having an inner cylindrical periphery inside said coil and an outer periphery concentrically surrounding said inner periphery; a plurality of axially extending, electrically non-conductive, strips, spaced circumferentially around said at least one winding, each strip including a plurality of folded sections, respective ones of said folded sections being fitted between respective adjacent turns, a plurality of air gaps being defined between said turns and said strips, said strips being arranged to permit radial and longitudinal air flow through said air gaps; means for generating an axial air flow along said inner cylindrical periphery of said coil, said axial air flow being adapted to reduce the air pressure at said inner periphery to induce outside air to flow through said air gaps;
said means for producing an axial air flow comprises a screen, said screen being adapted to block air flow through the center of one axial end of said coil and to define an axial gap between the circumferential periphery of said screen and said at least one winding of said coil, whereby air entering said axial gap is accelerated to produce said reduced air pressure along said inner periphery of said coil; andmeans for axially prestressing said at least one winding. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification