. An elementary book on electricity and magnetism and their applications. welding or bending heat, or evento melt the metal. The electrical method of heating has thisadvantage over the ordinary method by forge fire: the latterheats a piece of metal from the outside, while the former heatsall parts of the metal equally and at the same time the metalremains perfectly clean. Electric welding, as ordinarily carried on, consists of heatingthe pieces of metal to be welded while they are firmly buttedagainst each other. When the metals have been heated untilthey are soft at the points in contact, the
. An elementary book on electricity and magnetism and their applications. welding or bending heat, or evento melt the metal. The electrical method of heating has thisadvantage over the ordinary method by forge fire: the latterheats a piece of metal from the outside, while the former heatsall parts of the metal equally and at the same time the metalremains perfectly clean. Electric welding, as ordinarily carried on, consists of heatingthe pieces of metal to be welded while they are firmly buttedagainst each other. When the metals have been heated untilthey are soft at the points in contact, they are squeezed to-gether a certain amount, the current is shut off, and the weldis complete. This is the process developed by ProfessorElihu Thomson. The apparatus which is generally used inthe Thomson welding process is: (1) an alternator, usuallygiving a frequency of from 40 to 60 cycles per second; (2) awelding transformer with clamps and arrangements for auto-matically making the welds; (3) apparatus for controlling theamount of current supplied to the Fig. 344 a.—A 20-ton, 3-phase Heroult electric steel furnace fitted withthree 12-inch graphite electrodes.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmagnetism, bookyear19
