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1. (WO2001037619) METHOD AND APPARATUS TO FACILITATE RESTRIKING IN AN ARC-FURNACE

Pub. No.:    WO/2001/037619    International Application No.:    PCT/CA2000/001367
Publication Date: Sat May 26 01:59:59 CEST 2001 International Filing Date: Fri Nov 17 00:59:59 CET 2000
IPC: H05B 7/00
H05B 7/144
H05H 1/36
H05H 1/48
Applicants: CENTRE D'INNOVATION SUR LE TRANSPORT D'ÉNERGIE DU QUÉBEC
BEAUREGARD, François
FRANCOEUR, Bruno
Inventors: BEAUREGARD, François
FRANCOEUR, Bruno
Title: METHOD AND APPARATUS TO FACILITATE RESTRIKING IN AN ARC-FURNACE
Abstract:
To re-ignite efficiently an arc-furnace arc extending between an electrode and a material to be melt, a second energy supply is provided to maintain a plasma link between the electrode and the melting material when the arc-furnace arc is interrupted. The electrode is supplied by a large current power supply including a large current conductor having a self inductance and being connected to the electrode. The second energy supply is an electrical power supply wherein a high frequency bypass impedance is provided in a supply path to the large current conductor at a distance from a capacitive circuit to allow a high frequency resonant circuit to be formed by the conductor section between the capacitive circuit and the bypass impedance without adversely affecting the large current power supply of the arc furnace. The capacitive circuit comprises an HF power supply injected in resonance with the resonant circuit to build an oscillating voltage and use the oscillating voltage to inject an HF current between the electrode and the melting metal in order to maintain the plasma link.