| 摘要 |
An electrically conductive work-piece is rapidly heated by establishing a current flow in the work-piece that is the highest it can be without damaging circuit components. Such components include at least a transformer having a high-voltage, low-current primary winding and a low-voltage, high-current secondary winding and insulated cables connected to the secondary winding and terminated in one or more clamps that attach to the workpiece. The cables may be jumper-type cables and the clamps may be alligator-type clamps. Other types of clamps suitable for use with the present invention include a sliding clamp, a hinged clamp, and a wrap-around strap-type clamp. To limit current in the circuit to acceptable levels, it may be necessary to employ one or more resistive electrodes, or heater blocks, placed in the jaws of one or more of the clamps. Intimate thermal contact is established between the heater blocks and the work-piece such that heat generated in the heater blocks is conducted to the work-piece. Heater blocks of different configuration and/or composition are provided to present a range of resistances. For a particular application, a resistance is selected that will limit current flow to a level that will not damage the workpiece, the transformer and cables or the heater blocks themselves. In an alternative embodiment of the present invention, a conventional current limiter is used instead of resistive electrodes such that the maximum allowable current is consistently maintained through the work-piece.
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