A ball forming device includes a first current control circuit to control discharge current arranged between a leading end of a wire and one electrode of a discharge continuing power source for causing discharge current to flow after dielectric breakdown, a second current control circuit to control shunting of discharge current arranged between a discharge electrode and the other electrode of the discharge continuing power source, and a fixed resistor connected to the second current control circuit in parallel as a shunt and controls current flowing through the second current control circuit, thereby a discharge voltage value is adequately changed.

To provide a method and apparatus for manufacturing a joined member that inhibit occurrence of cracks in a joined member even when the joined portion is quenched when members are welded together. The method includes placing the first member D and the second member E with a joint target portion Df and a joint target portion Ef being in contact with each other, welding the joint target portions by heating, subjecting the first member D after the welding to a process for inhibiting occurrence of cracks, and tempering a portion where the first and second members have been welded to each other by electromagnetic heating. The apparatus includes a first electrode 11 to contact with the first member D; a second electrode 12 to contact with the second member E; and an induction heating coil 23 for performing induction heating of a portion where a joint target portions Df and Ef have been contacted and joined to each other, and the induction heating coil 23 is placed between the two electrodes 11 and 12 when the induction heating is performed.

Device (1) for the provision of electric power, wherein the device (1) comprises: at least one integrated temperature sensor (3-1, 3-2) which detects an operating temperature progression of at least one component (2-1, 2-2) of the device (1) and a monitoring unit (5) which, on the basis of the at least one detected operating temperature progression and the adjusted power, monitors the operating state of a device cooling arrangement of the device (1).

There is provided a power supply device that supplies an output current to an electric processing device which performs electric processing on workpieces. The device includes: a first power supply; a magnetic energy recovery switch that receives a current supplied from the first power supply, and converts the received current into the output current; and a control unit that controls the magnetic energy recovery switch such that an electric current frequency of the output current includes a first electric current frequency and a second electric current frequency which are different from each other within a one-time electric processing time using the electric processing device.

A seam welding system includes a pair of roller electrodes. The pair of roller electrodes hold a to-be-welded object between circumferential surfaces of the roller electrodes, rotate while holding the to-be-welded object between the circumferential surfaces, and perform seam welding on the to-be-welded object when a current flows between the roller electrodes while rotating and holding the to-be-welded object between the circumferential surfaces. To an electrode movement mechanism, the roller electrodes are mounted. The electrode movement mechanism moves the roller electrodes along a welding line of the to-be-welded object. Drive sources respectively rotate the roller electrodes and a joint of the electrode movement mechanism. A controller controls an amount by which the roller electrodes rotate based on a torque change in the drive sources so as to keep torques respectively acting on the roller electrodes within a predetermined range.

A seam welding system includes a pair of roller electrodes. The pair of roller electrodes hold a to-be-welded object between circumferential surfaces of the roller electrodes, rotate while holding the to-be-welded object between the circumferential surfaces, and perform seam welding on the to-be-welded object when a current flows between the roller electrodes while rotating and holding the to-be-welded object between the circumferential surfaces. To an electrode movement mechanism, the roller electrodes are mounted. The electrode movement mechanism moves the roller electrodes along a welding line of the to-be-welded object. Drive sources respectively rotate the roller electrodes and a joint of the electrode movement mechanism. A controller controls an amount by which the roller electrodes rotate based on a torque change in the drive sources so as to keep torques respectively acting on the roller electrodes within a predetermined range.

A data transmission method for a resistance welding current source during a welding operation generates welding pulses in an inverter with inverter switching elements cyclically with a switching frequency and pulse duration. The pulses are applied to a transformer primary side and rectified on the transformer secondary side by a rectifier with rectifier switching elements to form a resultant welding current. In a data transmission mode the impedance at the primary side is increased in the breaks in the welding operation, control pulses for initializing the data transmission mode are applied by a control device to the primary side and are detected on the secondary side. The rectifier switching elements of the secondary-side rectifier are actuated in a way corresponding to the data to be transmitted. The current on the primary side of the transformer is modulated with these data, and the data are thereby transmitted via the transformer.

Welding electrodes, methods, and vehicles are provided. The welding electrodes include a body that includes a weld face on a distal end of the body configured to contact a workpiece and apply an electrical current thereto. The body has a maximum diameter of 13 millimeters or less. The welding electrode includes an insulative material covering at least a portion of the body, the insulative material configured to mitigate current shunting upon contact between the insulative material and a workpiece of a workpiece stack-up while using the welding electrode to resistance weld the workpiece stack-up.

Welding electrodes, methods, and vehicles are provided. The welding electrodes include a body that includes a weld face on a distal end of the body configured to contact a workpiece and apply an electrical current thereto. The body has a maximum diameter of 13 millimeters or less. The welding electrode includes an insulative material covering at least a portion of the body, the insulative material configured to mitigate current shunting upon contact between the insulative material and a workpiece of a workpiece stack-up while using the welding electrode to resistance weld the workpiece stack-up.

The present disclosure relates to a projection welding machine, and more particularly, to a projection welding machine for avoiding an accident in which an operator's hand gets caught between an upper electrode unit and a lower electrode unit, and preventing a fault in welding operation from occurring due to incorrect seating of a nut on the lower electrode unit.