Improved method and arrangement for a martensite-free brazing process

An apparatus for brazing an electrically conducting connecting piece to a workpiece of electrically conducting material by means of a temperature-controlled brazing process in which the heat necessary for brazing is generated by striking an electric arc between a carbon electrode and the electrically conducting connecting piece, the apparatus comprising:

• (a) means for engaging an electrically conducting connecting piece towards a workpiece, including a guard ring and a carbon electrode;
• (b) means for supporting the carbon electrode including means for moving the carbon electrode between a position in which the carbon electrode engages the electrically conducting connecting piece in turn engaged by the means for engaging, and a retracted position in which the carbon electrode is lifted from the electrically conducting connecting piece;
• (c) a DC voltage unit for providing and applying a DC voltage of certain polarity between the electrically conducting connecting piece and the carbon electrode, wherein the DC voltage unit includes a voltage regulating unit;
• (d) a voltage sensor for measuring the voltage between the electrically conducting connecting piece and the carbon electrode;
• (e) a current sensor for measuring the electrical current passing through the carbon electrode;
• (f) processing means including means for generating an output signal controlling the voltage-regulating unit and further including means for calculating, in real time, continuously or continually, the electrical power developed in the arc;
• (g) switching means operable to connect the DC voltage unit in an electrical circuit with the carbon electrode and with the electrically conducting connecting piece whereby, when the means for engaging is applied, and the switching means is operated to close the electrical circuit, the means for supporting and moving raises the carbon electrode from the workpiece to strike an electric arc between the carbon electrode and the electrically conducting connecting piece;
• wherein the DC voltage unit is configured such that the certain polarity being that the DC voltage applied is using the carbon electrode as the negative pole, and using the electrically conducting connecting piece as the positive pole;
• and
• wherein the carbon electrode is provided with a pointy, tapering, or beveled end at the end facing the electric arc.

A cable shoe comprising:

• a front portion formed as a compact plate;
• and
• a back end formed to define a cable cavity for a cable;
• wherein the cable cavity extends into a tapering cavity to give the cable shoe a uniform cross section area along its length from the compact plate to the beginning of the cable cavity.