DC arc welding is performed by alternating a short-circuit period and an arc period. The arc period includes first to fourth periods. A welding current is raised to a first current value in the first period, lowered to a second current value with a time slope in the second period, kept at the second current value in the third period, and raised to a third current value then kept at the value in the fourth period. A wire feeding speed is constant throughout the short-circuit period and the arc period. In the second period, a welding output is under constant voltage control. In the third period and the fourth period, the welding output is under constant current control of the welding output.

Systems, methods, and apparatus to preheat welding wire are disclosed. An example welding assembly for a welding torch includes: a first contact tip configured to conduct welding current to a consumable electrode; a second contact tip configured to conduct preheating current to the consumable electrode; and a cooling body configured to transfer heat from at least the first contact tip to coolant and to conduct the welding current.

Apparatus and methods are provided for a welding-type power system that includes an engine configured to drive an electric generator to provide a first power output. An energy storage device to provide a second power output. A controller is configured to receive one or more control signals to provide a total power output to at least one of a welding-type output or an auxiliary type output, determine proportional values for the first power output and the second power output that add up to the total power output based on a power demand signal that indicates a contribution of the first power output and the second power output, control the engine to adjust speed based on the first power output value, and control a connection from the energy storage device to provide the second power output to the welding-type output based on the second power output value.

A solar-powered portable housing for a tool is also disclosed herein. The solar-powered portable housing for a tool can comprise a battery, one or more solar panels, a plug, a top enclosure, a bottom enclosure, a first slideable wall, and a first solar panel. The solar panels can be connectable to the battery. The solar panels can provide power source to the battery. The plug can allow the battery be charged through an electric power source. The top enclosure can be capable of housing a tool. The bottom enclosure can be capable of housing the battery. The battery can be capable of providing power to the tool. The first slideable wall can be mounted to one side of the housing. The first solar panel can be mounted to the first slideable wall.

A low voltage system and method for servicing welding equipment including a service tool that may provide a low voltage power source to the welding equipment, enabling the welding equipment to be tested in a low voltage mode of operation. The service tool may also run various test sequences on the welding equipment operating in a low voltage mode of operation to troubleshoot and diagnose any issues with the circuitry of the welding equipment.

A modular direct current power source is provided. One welding power supply system includes a plurality of hysteretic buck converters coupled in parallel. The hysteretic buck converters are configured to receive a common input and to provide combined output power to a common load based upon the common input.

An example welding or cutting circuit includes: an input leg comprising a capacitor coupled between a high bus and a low bus; a buck converter coupled in parallel with the input leg, wherein the buck converter comprises a first transistor, a first diode, and an output electrically coupled to a node between the first transistor and the first diode, and wherein the buck converter is configured to convert input voltage to current in an inductor coupled to the output of the buck converter; and a steering leg coupled in parallel with the input leg, wherein the steering leg is configured to control a rate at which the current in the inductor decreases, and wherein a current detector is positioned at the output to monitor the current, the current detector providing current level indications to a hysteretic controller, the hysteretic controller providing signals to the first transistor that control the transistor to an on state or an off state to control the voltage applied to the inductor.

Systems, methods, and apparatus to control weld current in a preheating system are disclosed. An example preheating power supply includes power conversion circuitry configured to output welding-type power via a first output power connector and a second output power connector, and a bypass path prevention circuit configured to prevent less than a threshold voltage applied to the first output power connector and the second output power connector from a different power supply from causing current to flow between the first output power connector and the second output power connector.

Systems and methods to control pulse welding are disclosed. An example welding-type system includes: power conversion circuitry configured to convert input power to welding-type power; and control circuitry configured to control the power conversion circuitry to output the welding-type power in a plurality of pulse cycles, each pulse cycle including background, ramp up, peak, and ramp down phases. Controlling the power conversion circuitry involves: during the background phase, controlling the power conversion circuitry in a voltage-controlled mode using a background voltage as a target voltage; during the ramp up phase, controlling the power conversion circuitry by changing the target voltage to a peak voltage; during the peak phase, controlling the power conversion circuitry using the peak voltage as the target voltage; and during the ramp down phase, controlling the power conversion circuitry by changing the target voltage to the background voltage.

A supplementary circuit for process supply lines of a welding torch or cutting torch has at least one connection device to a welding current source arranged on it, wherein electrical energy and other media are conveyed to the welding torch or cutting torch via the connection device and via a process supply line that is preferably held in a hose pack of the welding torch or cutting torch. Electrical energy for operating a peripheral device, such as a sensor, a drive unit or a controller for the drive unit, is branched or tapped off from at least one electrical process supply line without significantly affecting the electric arc process. The supplementary circuit provided for branching or tapping off the electrical energy is coupled in parallel onto the welding current circuit. This coupling is based on direct ohmic contact or on a galvanic coupling.