| 摘要 |
An electric resistance welder welds, hot reduces, tempers and planishes overlapped metal workpieces. The welder incorporates two transformers (50, 60) which are connected to two sets of wheel electrodes (26, 28 and 36, 38). Electric current from a first transformer (50) flows through workpieces (16) and returns through a second transformer (60). The first set of wheel electrodes (26, 28) creates a weld joint and the second set (36, 38), depending on the shape, area, and pressure of the wheels, either reduces the weld thickness, tempers the weld joint, or both. A control circuit (72) includes a current sensor (70) and power factor adjuster (80). The current sensor senses current flow through the first transformer during the welding process. As the current changes, particularly when the sets of wheel electrodes engage and disengage the workpieces, the power factor adjuster (72) adjusts the power factor to maintain constant heat to the workpieces. The electric resistance welder produces continuous, even tempered seam welds having reduced thickness.
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