A power supply system for an arc furnace, suitable for converting voltage of a three-phase electric power network into power supply voltage for the arc furnace, has an indirect AC/AC converter having a converter input and a converter output, and a matching apparatus having a matching transformer having a secondary side connectable to the arc furnace and a primary side operatively connected to the converter output. An input transformer group, inserted between the indirect AC/AC converter and the three-phase electric power network, has an input transformer primary side connectable to the three-phase electric power system, an input transformer secondary side connected to the converter input, a first input transformer and a second input transformer. Each of the first and second input transformers has three mutually displaced groups of secondary windings, each of which has a winding for each phase corresponding to a phase of the three-phase electric power network.

Realizing a constant-current control even in a stable state of a lamp without increasing a rated output of a power supply. In a stable state of the lamp in which a change value of a lamp voltage after a discharge lamp is turned on becomes less than a certain value, when the lamp voltage rises, a discharge lamp lighting control apparatus changes a current command value to perform a constant-current control. This change is a change from a first current command value at the time when the discharge lamp is turned on to a second current command value that is smaller than the former by a predetermined value. Using this second current command value, the constant-current control is performed. Even after that, the second current command value is changed to a smaller value every time the lamp voltage rises, and the constant-current control is performed using the second current command value.

A rectifier arrangement includes at least one input alternating voltage terminal to which an alternating current can be supplied, at least two output direct voltage terminals at which direct current can be tapped and at least one series circuit with at least two sub-modules connected in series. Each sub-module of the series circuit includes at least one converter module, an inverter module and a transformer module. Each sub-module of the series circuit additionally includes a rectifier module. The outputs of the rectifier modules are connected in parallel and form the output direct voltage terminals of the rectifier arrangement.

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.

A DC plasma arc furnace, a method of co-processing waste and metal, a method of producing energy by processing material using the furnace, and the products produced by the furnace are provided. Metal may be efficiently processed by the furnace via an increased organic content in other feedstock fed into the furnace.

Provided herein according to some embodiments is a dual cure additive manufacturing resin, comprising: (i) a light polymerizable component, (ii) a photoinitiator, (iii) a heat polymerizable component, and (iv) a non-reactive diluent, which resin is useful for the production of three-dimensional objects by additive manufacturing. Methods of using the same are also provided.

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

The present invention discloses a device for plasma arc melting through magnetostatic soft-contact stirring and compounding, which includes a furnace body, where a water-cooled copper crucible and a tungsten electrode are mounted in the furnace body, the tungsten electrode is located above the water-cooled copper crucible, and a groove for containing a metal raw material is opened in the water-cooled copper crucible; and a drive shaft penetrates through a side wall of the water-cooled copper crucible, one end, located at the exterior of the water-cooled copper crucible, of the drive shaft is connected with a stepper motor, one end, located in the water-cooled copper crucible, of the drive shaft is sleeved with two rotary tables, magnets having reverse magnetisms are interleaved in the rotary table, and the rotary tables are located on two sides of the groove.

The present invention relates to a plasma furnace which can efficiently treat various types of waste in large amounts. The plasma furnace comprises a melting chamber 101 for accommodating a melt, an upper surface forming the upper portion of the melting chamber 101 with a horizontal upper surface 111 and an inclined upper surface 112 having a slope with respect to the horizontal upper surface 111, a melt discharge portion 130 formed through a bottom surface of the melting chamber for discharging molten material therethrough, and an input apparatus 120 having a slope for inputting waste into the melting chamber 101, and the mixed type plasma torch 191, 192 provided on the inclined upper surface 112 with a slope for generating melting heat in the melting chamber 101.

An additive manufacturing apparatus makes it unnecessary to use a heater power supply, and makes it possible to attempt to reduce the cost, by effectively using an electron beam, includes: a conductive stage in a vacuum chamber; a conductive base plate on a top side of the stage; a metal-material supply device that supplies a metal material onto a top side of the base plate; an electron beam gun that irradiates, with an electron beam, the metal material supplied by the metal-material supply device, and melts and solidifies the metal material; a grounding circuit that grounds the stage and the base plate; and a controller that controls the metal-material supply device and the electron beam gun. The additive manufacturing apparatus includes a resistance heating element that is arranged between the stage and the base plate, and generates heat by a current produced by electron-beam emission from the electron beam gun.