Abstract: A controlled stop circuitry which frees the operator for carrying out other duties of cycle-interrupt time, by being automatically operable, when once activated, to partially raise the electrodes and to open the transformer switch, but only after the electrode current has decreased to a safe value. More particularly, the circuitry when actuated in a designated manner, interrupts an operating cycle by raising the electrodes, while simultaneously sensing the current supplied to them, and is effective, when the current decreases to a safe level, to automatically open the transformer switch and stop movement of the electrodes in partially raised positions. The circuitry also permits, as an option to the above procedure, the carrying out of the above steps, except that it delays opening of the transformer switch until the electrodes reach the top of their travel.

Abstract: The method consists of maintaining constant the magnitude of the interelectrode gap. For this purpose a melting current is measured and averaged for a constant predetermined time interval, whereafter a derivative of an averaged value of the melting current is determined, an amplitude of oscillations of the melting current relative to the averaged values of the melting current is detected, and a derivative of the rectified amplitude of oscillations of this current is determined. Then the obtained data are compared, and from the results of this comparison the melting current is controlled in such manner that said values are reduced to zero.The apparatus for controlling the process of casting thin walled ingots using the electroslag melting method comprises a melting current pick-up having an output connected to the inputs of a comparison unit and of a determination unit for determining an averaged value of the melting current.

Abstract: A kiln temperature controller is provided comprising a circuit for providing a first signal representative of a selectable kiln temperature and a temperature detection circuit for providing a second signal representative of the detected kiln temperature. The temperature detection circuit comprises first and second thermocouples disposed in the kiln and in the temperature controller, respectively. The first and second thermocouples are coupled in series and in opposite polarity. A solid state temperature sensing circuit is provided in the kiln temperature controller, the temperature sensing circuit being coupled in series with the first and second thermocouples and providing an output signal having a polarity opposite that of the second thermocouple to nullify ambient temperature variations of the kiln temperature controller.

Abstract: An arc generating electric system includes a first high-tension d.c. supply, electrodes and a high-voltage rectifier, the electrodes and the rectifier being connected in series, wherein the rectifier is in a forward position with respect to the first d.c. supply, and the arc generating system additionally includes a second high-tension d.c. supply connected in parallel to the rectifier, the second d.c. supply being in a forward position with respect to the first high-tension d.c. supply.