Abstract: The proposed apparatus comprises an arc-welding source, including a current pulse generator with a control circuit and a rectifier.A choke at the output of the rectifier is connected to the electrode-article gap, in series with the rectifier of the pulse generator. The rectifier is a fullwave rectifier and comprises two controlled thyristors and two uncontrolled diodes. As the apparatus is in operation, one of the thyristors becomes conducting during each alternating current half-cycle. Current pulses pass through the arc and choke and are added to the pedestal of the current that continuously flows from the rectifier through the welding circuit.

Abstract: A method for controlling flashing speed during resistance butt welding comprises measuring values of current density for at least two joints between parts being welded, converting them into d-c. voltages, detecting a maximum voltage value, comparing it to a preset d-c. voltage, the resultant difference value being used as flashing speed control parameter. An apparatus for carrying out the method comprises electric circuits whose number is equal to the number of joints being welded. Each circuit comprises a welding transformer and a circuit for conversion of flashing current density into d-c. voltage. A maximum signal detector comprises circuits for conversion of current density into d-c. voltages, whose number is equal to the number of joints being welded. The detector output is connected to the circuit for comparing a current voltage value to the preset one.

Abstract: An adjustable transformer comprising a core with two yokes and limbs, primary and secondary power windings, one of which has a supplemental section of turns, at least one of the transformer yokes being made of at least two parallel-connected controlled magnetic circuits forming an additional transformer opening making room for housing the supplemental section turns of the power winding. Each parallel-connected magnetic circuit is provided with bias windings connected to the control network and ensuring a magnetic switching of the supplemental section of turns of the power winding. The switching is a movement of the supplemental section of turns in and out of the transformer open-circuit magnetic flux field.