Abstract: A current-detection coil for a current transformer operating by the Rogowski principle has an insulating annular body made of a fiber-reinforced thermosetting plastic and manufactured as a single-piece solid body in a divisible mold. The parting line of a mold serving for manufacturing the annular body is in a flattened region on the outer periphery of the annular body and on a flattened region on the inner periphery. The annular body allows current transformers operating by the Rogowski principle to be manufactured that are capable of measuring in the entire range of currents that may occur and are resistant to mechanical and thermal stresses.

Abstract: A method for the local joining of stacked metal foils by electric pressure welding provides for receiving the foil stack between holding jaws which are arranged movably and tiltably. Thereby, pressure welds can be carried out successively at both ends of the foil stack without manual intervention. In an apparatus suitable for carrying out the method, the holding jaws consist of a highly heat-conducting material and contain a coolant canal. The clamping surfaces of the holding jaws are curved in the same direction and are interleaved. The curvature represents a substitute shape for a curvature given if the finished welded foil stack is in use.