Electrical cable jacket and conductor eccentricity detector including energizing coil formed about a toroid core and movable pickup coil
AssigneeBeta Instrument Company Limited
InventorJohn Kyriakis
Life of this patent
Estimating the term…
Abstract
An apparatus for use in determining the thickness of the insulated coating of an electrical cable manufactured in an extrusion process having means for generating an alternating current in the cable core coupled with means for detecting the magnetic field produced by the current flow in the cable such that in combination with a measurement of the distance from the detection means to the coated cable surface, a determination of coating thickness may be made.
Claims18
Apparatus for use in determining variations in the thickness of an insulated coating on an electrical cable along the length thereof, said electrical cable including an electrical conductor, said electrical cable being manufactured in an extrusion process wherein said insulated coating is extruded about said electrical conductor as said electrical conductor is drawn through an extrusion machine, comprising:
- generating means for generating an alternating current;
- a toroidal transformer core wound with a primary winding and circumferentially enclosing said electrical cable such that said electrical cable forms a secondary winding of said toroidal transformer core for inducing an alternating current in said electrical conductor when said primary winding is energized by said generating means;
- feedback means associated with said generating means for maintaining said alternating current in said electrical conductor at a constant level;
- detection means consisting of a search coil for detecting a varying magnetic field formed around said electrical cable resulting from the passage of said alternating current through said electrical conductor and for providing an output signal representative of the distance between said detection means and said electrical conductor in relation to the strength of said magnetic field, said detection means being located a predetermined and fixed distance from an exterior of said insulated coating;
- and
- processing means responsive to said output signal of said detection means for determining the thickness of said insulated coating by subtracting said predetermined and fixed distance between said detection means and said exterior of said insulated coating from said distance between said detection means and said electrical conductor and for generating an output signal representative of said thickness of said insulated coating.
The apparatus set forth in any preceding claim and further comprising a first and a second diameter measuring gauge means for determining the respective diameters of said conductor and said electrical cable and for outputting said respective diameters to said processing means to calibrate said processing means.
A method for determining variations in the thickness of an insulation jacket on an electrical cable along the length thereof, said electrical cable including an electrical conductor, said electrical cable being manufactured in an extrusion process wherein said insulation jacket is extruded about said electrical conductor cable as said electrical conductor is drawn through an extrusion machine, comprising the steps of:
- (a) passing said electrical cable through a central opening of a toroidal core, said toroidal core having a primary winding wound thereon;
- (b) applying an alternating electrical current to said primary winding of said toroidal core to induce an alternating electrical current to flow within said electrical conductor;
- (c) providing detection means consisting of a search coil disposed a predetermined and fixed distance from an exterior of said electrical cable for sensing a time varying magnetic flux formed around said electrical cable resulting from the passage of said alternating current through said electrical conductor and for providing an output signal representative of the distance between said detection means and said electrical conductor in relation to the strength of said magnetic flux;
- and
- (d) providing processing means in communication with said detection means for calculating the thickness of said insulation jacket from said output signal of said detection means and for producing a further output signal representative of said thickness of said insulation jacket.
Dependencies are inferred from the claim text.