A method for spot-welding metallic materials includes: sandwiching the metallic materials with a pair of electrodes; a pre-heating step for pre-heating a region different from a given region which should be welded by applying electric power having a high frequency to the pair of electrodes; and a welding step for spot-welding a given region of the metallic materials by applying electric power for welding to the pair of electrodes. The heating time in the pre-heating step and that in the welding step are independently controlled.

A welding equipment for metallic materials capable of performing heat treatment such as tempering based on partial heating in spot welding is provided. The welding equipment sandwiches metallic materials with a pair of electrodes, and heats different regions of the metallic materials by energization, with the pair of electrodes maintained at the same position with respect to the metallic materials. The welding equipment includes a first heating means connected to the pair of electrodes for heating and welding the internal region of the circle defined by projecting the cross-sectional area of the axis of the electrodes on the metallic materials by applying power having a low first frequency, a second heating means for heating a ring-shaped region along the circle by applying power having a second frequency that is higher than the first frequency, and an energization control unit for independently controlling the first and the second heating means.

A welding equipment for metallic materials capable of performing heat treatment such as tempering based on partial heating in spot welding is provided. The welding equipment sandwiches metallic materials with a pair of electrodes, and heats different regions of the metallic materials by energization, with the pair of electrodes maintained at the same position with respect to the metallic materials. The welding equipment includes a first heating means connected to the pair of electrodes for heating and welding the internal region of the circle defined by projecting the cross-sectional area of the axis of the electrodes on the metallic materials by applying power having a low first frequency, a second heating means for heating a ring-shaped region along the circle by applying power having a second frequency that is higher than the first frequency, and an energization control unit for independently controlling the first and the second heating means.

Methods and apparatus for detecting a leakage current are disclosed. An example apparatus to monitor a welding-type system includes: a test signal generator configured to output a test signal to a welding-type circuit; and a lock-in amplifier configured to: receive a reference signal based on the test signal; measure a leakage current in the welding-type circuit based on the reference signal; and generate an output signal representative of the leakage current.

An automatically flushing water heater maintenance system may be provided, the system including a water heater and a water heater controller. The water heater may include an inlet, an outlet, and a flush outlet having a first control valve in flow communication therewith. The first control valve may be configured to control a flow of water and sediment through the flush outlet out of the water heater. The water heater controller may be configured to communicate with the first control valve by transmitting a first control signal to the first control valve, the first control signal configured to cause the first control valve to open or close as part of an automatic flushing process. As a result of the flushing, the useful life of the water heater may be extended, and/or water heater leakage alleviated. Insurance discounts may be provided based upon using the automatic water heater flushing functionality.

A method and apparatus for providing welding-type power and auxiliary power includes an input circuit, a welding-type output power circuit, an auxiliary power circuit, and a controller. The input circuit receives input power and provides power to a common bus. The welding-type output power circuit receives power from the common bus and provides welding-type output power. The auxiliary power circuit receives power from the common bus and provides non-isolated auxiliary output power. The controller controls the auxiliary power circuit and the welding-type output power circuit.

An automatically flushing water heater maintenance system may be provided, the system including a water heater and a water heater controller. The water heater may include an inlet, an outlet, and a flush outlet having a first control valve in flow communication therewith. The first control valve may be configured to control a flow of water and sediment through the flush outlet out of the water heater. The water heater controller may be configured to communicate with the first control valve by transmitting a first control signal to the first control valve, the first control signal configured to cause the first control valve to open or close as part of an automatic flushing process. As a result of the flushing, the useful life of the water heater may be extended, and/or water heater leakage alleviated. Insurance discounts may be provided based upon using the automatic water heater flushing functionality.

A method of monitoring a manufacturing status of an electric resistance welded pipe manufactured by shaping a steel strip into a pipe and butt welding both end parts of the steel strip in a width direction along a lengthwise direction includes: arranging an imaging unit in a gas shield nozzle having an opening opposing a region in which both of the end parts of the steel strip in the width direction are butt welded and shielding the region with inert gas by ejecting the inert gas onto the region through the opening, the imaging unit having a visual filed including the region; and determining quality of a butt-welded part based on an image shot by the imaging unit.

A method of monitoring a manufacturing status of an electric resistance welded pipe manufactured by shaping a steel strip into a pipe and butt welding both end parts of the steel strip in a width direction along a lengthwise direction includes: arranging an imaging unit in a gas shield nozzle having an opening opposing a region in which both of the end parts of the steel strip in the width direction are butt welded and shielding the region with inert gas by ejecting the inert gas onto the region through the opening, the imaging unit having a visual filed including the region; and determining quality of a butt-welded part based on an image shot by the imaging unit.

A method and apparatus for providing welding-type power and auxiliary power includes an input circuit, a welding-type output power circuit, an auxiliary power circuit, and a controller. The input circuit receives input power and provides power to a common bus. The welding-type output power circuit receives power from the common bus and provides welding-type output power. The auxiliary power circuit receives power from the common bus and provides non-isolated auxiliary output power. The controller controls the auxiliary power circuit and the welding-type output power circuit.