Measurement of electrical variables on a dc furnace
AssigneeMintek
InventorsIan James BARKER, Quinn Gareth REYNOLDS, Christopher James HOCKADAY, Dominic Timothy JORDAN
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Abstract
A method of detecting an open arc in a DC plasma arc furnace which is based on detecting a linear decrease in the log of the magnitude of the frequency spectrum of the voltage between the anode and cathode.
Claims8
A method of detecting an open arc in a DC plasma arc furnace which includes a power supply, and an anode and a cathode connected to the power supply, the method including the steps of:
- a) measuring the magnitude of voltage between the anode and the cathode over a time interval;
- b) expressing the voltage magnitude as a function of time, over the time interval;
- c) deriving from the function of time a frequency spectrum of the voltage for the time interval;
- and
- d) examining the frequency spectrum of the voltage to determine a characteristic in the frequency spectrum which is indicative of an open arc in the furnace.
Apparatus for detecting an open arc produced by an electrode in a DC plasma arc furnace which includes a power source and an anode and a cathode which are connected to the power source, the apparatus including a circuit for measuring the magnitude of a voltage between the anode and the cathode over a time interval, a processor which produces a frequency spectrum of the voltage over the time interval and a discriminator which examines the frequency spectrum of the voltage to determine a characteristic in the frequency spectrum which is associated with an open arc in the furnace, and wherein the characteristic is a substantially linear decrease in the log of the magnitude of the frequency spectrum as a function of the log of the frequency.
Dependencies are inferred from the claim text.