AIR-CORE CHOKE COIL AND METHOD OF MANUFACTURING IT

摘要

AIR-CORE CHOKE COIL 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 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 shortcircuit conditions.