Power supply circuit for a direct current arc furnace
First Claim
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1. A power supply circuit for providing a continuous DC arc between two electrodes of an electric arc furnace, comprising:
- a three-phase AC power source for providing an AC current and an AC voltage;
rectifier means having three input terminals and first and second output terminals, one of said electrodes being connected to the first output terminal of said rectifier means;
a DC inductance having a first terminal connected to the second output terminal of said rectifier means and a second terminal connected to the second of said electrodes;
transformer means having primary windings and secondary windings;
first, second and third linear reactors for producing a change in phase angle between the AC current and AC voltage in response to a change in DC arc length to control the DC arc current and power input to the furnace; and
circuit means connecting the linear reactors and the transformer means in series between the AC power source and the rectifier means.
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Abstract
A power supply circuit for providing a continuous DC arc between two electrodes of an electric arc furnace comprises a three-phase AC power source, transformer means having primary and secondary windings and three linear reactors. One of the outputs of a three-phase full-wave rectifier is connected to one of the furnace electrodes. The other output of the rectifier is connected through a DC inductance to the second furnace electrode. The linear reactors and the transformer means are connected in series between the AC power source and the rectifier.
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Citations
21 Claims
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1. A power supply circuit for providing a continuous DC arc between two electrodes of an electric arc furnace, comprising:
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a three-phase AC power source for providing an AC current and an AC voltage; rectifier means having three input terminals and first and second output terminals, one of said electrodes being connected to the first output terminal of said rectifier means; a DC inductance having a first terminal connected to the second output terminal of said rectifier means and a second terminal connected to the second of said electrodes; transformer means having primary windings and secondary windings; first, second and third linear reactors for producing a change in phase angle between the AC current and AC voltage in response to a change in DC arc length to control the DC arc current and power input to the furnace; and circuit means connecting the linear reactors and the transformer means in series between the AC power source and the rectifier means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 13, 14, 17, 19, 20, 21)
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8. A power supply circuit for providing a continuous DC arc between two electrodes of an electric arc furnace comprising:
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a three-phase AC power source for producing an AC current and an AC voltage; transformer means having primary windings and secondary windings, the primary windings being connected to the AC power source; first, second and third linear reactors having first and second terminals for producing a change in phase angle between AC current and AC voltage in response to a change in DC arc length to control the DC arc current and power input to the furnace, the first terminal of each of said reactors being connected to the secondary windings of the transformer means; rectifier means having three input terminals and first and second output terminals, the rectifier means input terminals being connected to the second terminals of each of the linear reactors, one of said electrodes being connected to the first output terminal of said rectifier means; and a DC inductance having a first terminal connected to the second output terminal of said rectifier means and a second terminal connected to the second of said electrodes. - View Dependent Claims (9, 10, 11, 12, 15, 18)
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16. A power supply circuit for providing a continuous DC arc between two electrodes of an electric arc furnace, comprising:
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an AC power source for producing an AC current an AC voltage; transformer means having primary windings connected with the AC power source and secondary windings; rectifier means having an AC input connected with the secondary windings of the transformer means and a DC output connected with the two electrodes of the furnace; and linear reactor means provided in series with the transformer means between the AC power source and the rectifier means for producing a change in phase angle between the AC current and AC voltage in response to a change in DC arc length to control the DC arc current and power input to the furnace.
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Specification