Electromagnetic device
AssigneeABB AB
InventorMATS LEIJON
Life of this patent
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Abstract
An electromagnetic device comprises a magnetic field generating electrical circuit including a winding (1) having at least one electrical conductor (2). The winding comprises a solid insulation (4) surrounded by outer and inner layers (3, 5) serving for equalization of potential and having semiconducting properties. Said at least one electrical conductor (2) is arranged interiorly of the inner semiconducting layer (3). The invention also relates to methods for electric field control and production of a magnetic circuit as well as use of a cable for obtaining a winding.
Claims42
Electromagnetic device comprising a magnetic field generating electric circuit including at least one electric conductor having an insulation system, characterized in that the insulation system comprises an electric insulation (4) formed by a solid insulation material and exteriorly of the insulation an outer layer (5) which has an electrical conductivity which is higher than that of the insulation to make the outer layer capable, by connection to earth or otherwise a relatively low potential, of operating to equalise potential and substantially enclose the electrical field, arising as a consequence of said electric conductor (2), inwardly of the outer layer (5).
A device according to claim (1), characterized in that the insulation system comprises, interiorly of the insulation (4), an inner layer (3), that said at least one electric conductor (2) is located interiorly of the inner layer (3) and that the inner layer has an electrical conductivity which is lower than the conductivity of the electric conductor but sufficient for the inner layer to operate for equalisation of potential and accordingly for equalisation with respect to the electrical field exteriorly of the inner layer (3).
Electromagnetic device comprising a magnetic field generating electric circuit including at least one electric conductor (2) having an insulation system, characterized in that the insulation system comprises an electric insulation (4) formed by a solid insulating material and inwardly thereof an inner layer (3), that said at least one electric conductor (2) is provided inwardly of the inner layer (3), that the inner layer has an electrical conductivity which is lower than that of the electric conductor but sufficient for making the inner layer to function equalizing with respect to the electric field exteriorly of the inner layer (3).
Electromagnetic device comprising at least one electric conductor (2) having an insulation system, characterized in that the insulation system comprises at least two potential layers (3, 5) and between those layers an electric insulation (4) consisting of a solid insulation material, and that the potential layers and the solid insulation present substantially similar thermal properties.
A device according to any preceding claim, characterized in that said at least one conductor (2) forms at least one induction turn.
A device according to any preceding claim, characterized in that the inner and/or outer layer (3, 5) comprises a semiconducting material.
A device according to any preceding claim, characterized in that the inner layer (3) and/or the outer layer (5) has a resistivity in the range 10−6 Ωcm-100 kΩcm, suitably 10−3-1000 Ωcm, preferably 1-500 Ωcm.
A device according to any preceding claim, characterized in that the inner layer (3) and/or the outer layer (5) has a resistance which per length meter of the layer is in the range 50 μΩ-5 MΩ.
A device according to any preceding claim, characterized in that the solid insulation (4) and the inner layer (3) and/or the outer layer (5) are formed by polymeric materials.
A device according to any preceding claim, characterized in that the inner layer (3) and/or the outer layer (5) and the solid insulation (4) are rigidly connected to each other over substantially the entire interface.
A device according to any preceding claim, characterized in that the inner layer (3) and/or the outer layer (5) and the solid insulation (4) are formed by materials presenting substantially equal thermal coefficient of expansion.
A device according to any preceding claim, characterized in that the solid insulation (4) has been obtained by extrusion.
A device according to claim 15, characterized in that the conductor (2) and its insulation system constitutes a winding formed by means of a flexible cable (1).
A device according to any preceding claim, characterized in that the inner layer (3) and/or the outer layer (5) comprises a polymeric material containing an electrically conducting constituent.
A device according to any preceding claim, characterized in that the conductor (2) and its insulation system is designed for high voltage, suitably in excess of 10 kV, in particular in excess of 36 kV and preferably more than 72,5 kV.
A device according to any preceding claim, characterized in that it is constituted of a rotating electric machine.
A method for electric field control in an electromagnetic device comprising a magnetic field generating circuit having at least one winding (1) with at least one electric conductor (2) and an electric insulation (4) present externally thereof, characterized in that the insulation (4) is formed by a solid insulation material and that an outer layer (5) is provided externally of the insulation, said outer layer (5) being connected to ground or otherwise a relatively low potential and having an electrical conductivity being higher than the conductivity of the insulation (4) but lower than the conductivity of the electrical conductor (2) so as to function for equalization of potential and cause the electrical field to be substantially enclosed in the winding internally of the outer layer (5).
A method in production of a magnetic circuit for a rotating electric machine, where the magnetic circuit is arranged in the stator and/or rotor of the rotating electric machine and comprises a magnetic core (8) having slots (10) for a winding, said slots being formed with openings (12), characterized in that a flexible cable (1) is used as a winding and that this cable is threaded into the openings (12).
Use of a cable comprising at least one electric conductor (2) with an insulation system including at least two potential layers and between these layers an insulation made of a solid electric insulation material, where the potential layers and the solid insulation exhibit substantially similar thermal properties, for forming a magnetic field generating winding in an electromagnetic device.
Dependencies are inferred from the claim text.