A method of resistance spot welding workpiece stack-ups of different combinations of metal workpieces with a single weld gun using the same set of welding electrodes is disclosed. In this method, a set of opposed welding electrodes that include an original shape and oxide-disrupting structural features are used to resistance spot weld at least two of the following types of workpiece stack-ups in a particular sequence: (1) a workpiece stack-up of two or more aluminum workpieces; (2) a workpiece stack-up that includes an aluminum workpiece and an adjacent steel workpiece; and (3) a workpiece stack-up of two or more steel workpieces. The spot welding sequence calls for completing all of the aluminum-to-aluminum spot welds and/or all of the steel-to-steel spot welds last.

Described herein are methods and system for welding, for example, girders. The method may include activating a homopolar generator. The method may include applying a force to two metal girders at a desired coupling joint. The method may include generating an electrical pulse using the homopolar generator and conducting the electrical pulse to the desired coupling joint to increase a temperature of the girders. The method may include forming a weld at the desired coupling joint attaching the two metal girders at the desired coupling joint. In some embodiments, the homopolar generator may include a radial bearing rotor including a rotatable shaft and a bearing assembly. The bearing assembly may include nonmagnetic bearings. The homopolar generator may include a field coil. The homopolar generator may include a brush actuation mechanism which when activated engages a plurality of brush devices to the radial bearing rotor.

A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

A switch device (10) and method for generation of energy for operating the switch device (10), wherein the switch device (10) is provided with a drive unit (120) interacting with an actuation device operable by a user, and with a moving device (130) configured to be set in motion by the drive unit (120), and with an energy harvester (132, 140, 140a) for providing energy to the switch device (10) in dependence on a motion of the moving device (130), such that energy for commands or other operations is provided to the switch device (10). The moving device (130) is configured to be repeatedly repositioned in relation to a defined zero position, as long as it has kinetic energy, in order to provide kinetic energy which can be converted in electric energy by the energy harvester (132, 140, 140a). Such an electromechanical device for generating energy can ensure wireless operation of the switch device (10) without the need of batteries or any other kind of power supply.

An interface module is described for replacing a light switch assembly in an electrical switch box, the electrical switch box having an input wire coupled to a power source, an output wire coupled to a first lighting device, and at least one threaded bore. The interface module includes a housing, a first terminal mounted on the housing and connected to the input wire, a second terminal mounted on the housing and connected to the output wire, a first switch component configured to activate and deactivate the lighting device, a control configured to operate the first switch component, a user interface coupleable to the first terminal to receive operating power, and a wireless transmitter configured to transmit signals indicative of inputs received through the user interface, the wireless transmitter being configured to receive power from the first terminal.

To provide a power supply switching circuit which avoids an increase in current consumption. A power supply switching circuit includes MOS transistors provided between power supply input terminals and an output terminal, which have gates connected to each other and backgates connected to each other and are connected in series.

The invention relates to projection welding of a second metal sheet above a first metal sheet (50), wherein the first metal sheet is of a non-ferrous metal or metal alloy having as main component aluminum or magnesium, wherein the first metal sheet comprises an elongate projection that locally extends above the main upper surface of the first metal sheet to come into contact with the main lower surface of the second metal sheet, wherein the projection comprises an upper surface having a convex first section (65) with a first radius (R1) that defines in its middle the top height of the upper surface with respect to the main upper surface of the first metal sheet, and a convex second section (64) with a second radius (R2) along both elongate sides that merge into the first section, wherein the first radius is larger than the second radius.

The invention relates to projection welding of a second metal sheet above a first metal sheet (50), wherein the first metal sheet is of a non-ferrous metal or metal alloy having as main component aluminum or magnesium, wherein the first metal sheet comprises an elongate projection that locally extends above the main upper surface of the first metal sheet to come into contact with the main lower surface of the second metal sheet, wherein the projection comprises an upper surface having a convex first section (65) with a first radius (R1) that defines in its middle the top height of the upper surface with respect to the main upper surface of the first metal sheet, and a convex second section (64) with a second radius (R2) along both elongate sides that merge into the first section, wherein the first radius is larger than the second radius.

A system and method of braze resistance spot welding of an aluminum component to a galvanized steel component involve providing an aluminum-side electrode having a first tip defining a rounded shape, providing a galvanized steel-side electrode having a second tip defining a flat shape, depositing a braze filler material between the aluminum and galvanized steel components at a desired location for a spot weld, performing a pre-heat including providing a first current across the electrodes for a first period such that the braze filler melts and removes a portion of a zinc coating from the galvanized steel component, and after performing the pre-heat, performing a spot weld between the aluminum and galvanized steel components by providing a second current across the electrodes for a second period such that the aluminum melts and the galvanized steel does not melt, wherein the second current is greater than the first current.