A temperature sensor including a sapphire optical fiber and a nanoporous cladding layer covering at least a portion of the sapphire optical fiber.

A non-linear load in the form of an arc furnace with an upstream furnace transformer is supplied with electric power from a power supply device with a plurality of converter units. The converter units have a plurality of main modules with inputs connected to a respective phase of a three-phase grid. The converter units have a common star point between the main modules and the primary side of the furnace transformer. Each main module has a series circuit with a coupling inductance and a plurality of submodules. The submodules have a bridge circuit with four self-commutated semiconductor switches and a bridge path with a storage capacitor between input and output. The semiconductor switches of the submodules can each be switched independently of the semiconductor switches of the other submodules of the same main module and of the other main modules.

A non-linear load in the form of an arc furnace with an upstream furnace transformer is supplied with electric power from a power supply device with a plurality of converter units. The converter units have a plurality of main modules with inputs connected to a respective phase of a three-phase grid. The converter units have a common star point between the main modules and the primary side of the furnace transformer. Each main module has a series circuit with a coupling inductance and a plurality of submodules. The submodules have a bridge circuit with four self-commutated semiconductor switches and a bridge path with a storage capacitor between input and output. The semiconductor switches of the submodules can each be switched independently of the semiconductor switches of the other submodules of the same main module and of the other main modules.

An electric power apparatus for an electric arc furnace comprises at least one electrode and is connectable to a power network to supply to the electrode the electric energy to generate an electric arc to melt a metal mass. The apparatus comprises an electric regulation unit interposed and connected to the power network and to the electrode and configured to regulate at least one electric quantity for powering the electrode. The apparatus comprises at least one detection device to detect the electric quantity, interposed between the electrode and the electric regulation unit, a positioning device to move the at least one electrode nearer to/away from the metal mass to be melted and a control and command unit.

A heating control system and method for switching on a heating load, wherein the heating load is controllable via forward-phase control, and wherein, at a particular instant in time, the forward-phase control has a corresponding phase control angle, where the heating load is switched on via a specifiable initial phase control angle and an ascertained effective current and a definable switch-on current curve are taken into account in order to determine the subsequent phase control angles such that an efficient cold start with any heating loads can be performed.

A heating control system and method for switching on a heating load, wherein the heating load is controllable via forward-phase control, and wherein, at a particular instant in time, the forward-phase control has a corresponding phase control angle, where the heating load is switched on via a specifiable initial phase control angle and an ascertained effective current and a definable switch-on current curve are taken into account in order to determine the subsequent phase control angles such that an efficient cold start with any heating loads can be performed.

The invention provides for a DC brush-arc furnace comprising a vessel 12 and first and second electrodes 16, 18. A first DC power supply 20 supplies power to the electrodes. A first conductor 26 extends parallel to the first electrode, so that a first current flows in a first direction through the first conductor and in a second opposite direction in the first electrode. A second conductor 28 extends parallel to the second electrode, so that the current flows in the first direction in the second electrode and in the second direction in the second conductor. An arc deflection compensation system 30 comprises a second DC power supply 32 and a compensation circuit 34 comprising a first compensation conductor 36 and a second compensation conductor 38. The second DC power supply causes a second current to flow through the first compensation conductor in the first direction and through the second compensation conductor in the second direction.

The invention provides for a DC brush-arc furnace comprising a vessel 12 and first and second electrodes 16, 18. A first DC power supply 20 supplies power to the electrodes. A first conductor 26 extends parallel to the first electrode, so that a first current flows in a first direction through the first conductor and in a second opposite direction in the first electrode. A second conductor 28 extends parallel to the second electrode, so that the current flows in the first direction in the second electrode and in the second direction in the second conductor. An arc deflection compensation system 30 comprises a second DC power supply 32 and a compensation circuit 34 comprising a first compensation conductor 36 and a second compensation conductor 38. The second DC power supply causes a second current to flow through the first compensation conductor in the first direction and through the second compensation conductor in the second direction.

A temperature sensor according to the disclosure herein includes an optical fiber structured to produce a thermal emission representative of a molten steel into which the temperature sensor is inserted; a cladding layer covering at least a portion of the optical fiber; and a spectrometer configured to receive the thermal emission from the optical fiber and to generate, in response, a radiation spectrum indicative of a temperature of the molten steel.

A temperature sensor according to the disclosure herein includes an optical fiber structured to produce a thermal emission representative of a molten steel into which the temperature sensor is inserted; a cladding layer covering at least a portion of the optical fiber; and a spectrometer configured to receive the thermal emission from the optical fiber and to generate, in response, a radiation spectrum indicative of a temperature of the molten steel.