Abstract: In order to increase output of pipe straightening devices, there is provided a driving unit between a preparatory station for the pipes and a feeding station which advances the pipes from the preparatory station in axial direction one after the other in the feeding station. The feeding station includes a succession of rotation symmetrical guiding elements supported for rotation about axes which extend parallel to the feeding path for the pipes. The guiding bodies prevent striking of unbalanced pipes against the feeding unit and permit axial feeding of the pipes in a straightening station.

Abstract: A rotatable shaft has a roller electrode mounted on it for rotation therewith. A transformer and a rectifier are structurally integrated to form a unit which is also mounted on the shaft for rotation with it, and serve to convert high-voltage low-amperage net current into low-voltage high-amperage DC current. Slip rings are mounted on the shaft to transmit electrical current to the unit for supply to the roller electrode.