An electrical arrangement for an electric arc furnace (1) operated with alternating current has a converter (2) which converts mains voltage (U), having a mains frequency (f), of a supply grid (3) into primary voltage (U) having a furnace frequency (f). A furnace transformer (4) of the electrical arrangement transforms the primary voltage (U) into a secondary voltage (U). The secondary voltage (U) is supplied to a number of electrodes (6) of the electric arc furnace (1). The electrodes (6) are arranged in a furnace vessel (8) of the electric arc furnace (1). They apply electric arcs (10) to a melt material (9) in the furnace vessel (8). The secondary voltage (U) is also supplied to a capacitor assembly (7) which is on the output side of the furnace transformer (4) and to which the furnace transformer (4) is connected on the output side. The converter (2) is controlled by a control device (5) such that a primary voltage (U) output from the converter (2) to the furnace transformer (4) has a furnace frequency (f) which is at least ten times the mains frequency (f) and/or is greater than 1 kHz.

An electrical arrangement for an electric arc furnace (1) operated with alternating current has a converter (2) which converts mains voltage (U), having a mains frequency (f), of a supply grid (3) into primary voltage (U) having a furnace frequency (f). A furnace transformer (4) of the electrical arrangement transforms the primary voltage (U) into a secondary voltage (U). The secondary voltage (U) is supplied to a number of electrodes (6) of the electric arc furnace (1). The electrodes (6) are arranged in a furnace vessel (8) of the electric arc furnace (1). They apply electric arcs (10) to a melt material (9) in the furnace vessel (8). The secondary voltage (U) is also supplied to a capacitor assembly (7) which is on the output side of the furnace transformer (4) and to which the furnace transformer (4) is connected on the output side. The converter (2) is controlled by a control device (5) such that a primary voltage (U) output from the converter (2) to the furnace transformer (4) has a furnace frequency (f) which is at least ten times the mains frequency (f) and/or is greater than 1 kHz.

A joining method for connecting a first component to a second component without pre-punching. The first component and the second component are positioned relative to one another prior to the connection by an auxiliary joining element, which is joined via a joining device to the components positioned relative to one another. The auxiliary joining element firstly passes through the first component without pre-punching and is then connected to the second component without pre-punching. Before the components are connected by the auxiliary joining element, the first component is thermally pre-treated at the joining area via an electric arc formed between the first component and an electrode of the joining device. A heat-affected zone is formed on the first component in the joining area, and the first component in is weakened or melted in the heat-affected zone.

A joining method for connecting a first component to a second component without pre-punching. The first component and the second component are positioned relative to one another prior to the connection by an auxiliary joining element, which is joined via a joining device to the components positioned relative to one another. The auxiliary joining element firstly passes through the first component without pre-punching and is then connected to the second component without pre-punching. Before the components are connected by the auxiliary joining element, the first component is thermally pre-treated at the joining area via an electric arc formed between the first component and an electrode of the joining device. A heat-affected zone is formed on the first component in the joining area, and the first component in is weakened or melted in the heat-affected zone.

Methods of powering a heat engine with a remote lasers are disclosed, where the ambient air surrounding the engine is used as the working fluid. All methods include inputting the ambient air into the engine, absorbing laser optical radiation, turning it into heat, supplying the heat to the air, harvesting mechanical work from expanding air and releasing the air back into surrounding atmosphere.

The present disclosure provides a metallurgical electric furnace, and a smelting method for the metallurgical electric furnace. The metallurgical electric furnace includes a furnace body, an oxygen lance and a coal lance, wherein the furnace body is provided with a furnace chamber; the oxygen lance is located on a side wall of the furnace chamber and is used for blowing oxygen into the slag promoting the smelting process, and the outlet of the oxygen lance is higher than the slag; and the coal lance is located on the side wall of the furnace chamber beside the oxygen lance and is used for spraying coal into the slag, and the outlet of the coal lance is higher than the slag.

A configuration of switches added to a line control circuit allows for switching back and forth between a configuration featuring a series-connected thyristor switch and reactor and a configuration featuring a parallel-connected thyristor switch and reactor. Connecting the reactor in series with the thyristor switch allows a controlled high-impedance circuit configuration that is particularly well adapted for cold furnace start-ups and furnace idling. In this manner, there is reduced need for such equipment as extra startup transformers, alternate low-voltage power supply configurations and temporary specialty electrical apparatus for cold furnace start-ups.

A configuration of switches added to a line control circuit allows for switching back and forth between a configuration featuring a series-connected thyristor switch and reactor and a configuration featuring a parallel-connected thyristor switch and reactor. Connecting the reactor in series with the thyristor switch allows a controlled high-impedance circuit configuration that is particularly well adapted for cold furnace start-ups and furnace idling. In this manner, there is reduced need for such equipment as extra startup transformers, alternate low-voltage power supply configurations and temporary specialty electrical apparatus for cold furnace start-ups.

A plasma processing apparatus includes a processing chamber including a sidewall; a mounting table including a lower electrode and provided in the processing chamber; an upper electrode arranged to face the lower electrode in a first direction; a high frequency power supply configured to apply a high frequency power for plasma generation to the upper electrode; a gas supply system for supplying a processing gas into the processing chamber; and a grounding unit connected to a ground potential. A first space is defined between the mounting table and the sidewall. A second space is defined between the upper electrode and the lower electrode. The grounding unit is configured to move independently from the upper electrode in the first direction in a third space which extends to the first space in the first direction and also to the second space in a second direction perpendicular to the first direction.

A plasma processing apparatus includes a processing chamber including a sidewall; a mounting table including a lower electrode and provided in the processing chamber; an upper electrode arranged to face the lower electrode in a first direction; a high frequency power supply configured to apply a high frequency power for plasma generation to the upper electrode; a gas supply system for supplying a processing gas into the processing chamber; and a grounding unit connected to a ground potential. A first space is defined between the mounting table and the sidewall. A second space is defined between the upper electrode and the lower electrode. The grounding unit is configured to move independently from the upper electrode in the first direction in a third space which extends to the first space in the first direction and also to the second space in a second direction perpendicular to the first direction.