Abstract: A device for testing elongated objects, particularly wires, optionally with cross-sectional irregularities, which has a rotating test head traversed by the object and on which is provided a probe, particularly an eddy current probe, provided on rotary probe holding means and guided on circular paths about the object. For the change of the radial spacing between the object and the probe with the test head rotating, externally controllable e.g. by a sensor for irregularities, the device has a switching device with two inherently stable switching states, whereof one can correspond to a testing position near the object and another to a raised position further removed from the object and which can be rapidly set for protecting the probes.

Abstract: A driver for oblong material having three arms carrying the driving elements which swing vertically with respect to the material path of movement. For a selected setting angle of the arms, the point of contact of a driving roller with the material is displaced such that, on the diameter of the test material becoming smaller, the point of contact is moved towards the edge of the roller. This feature has three desirable consequences: First, wear is not concentrated on a single track of the roller surface; second, the pressing-on force of the rollers is decreased with the decreasing diameter of the test material; and third, when using three rollers, the seeing angle can be adjusted such that for the narrowest approach of the rollers possible, one edge each of a roller meets with the respective edges of the other rollers in one point.

Abstract: An eddy current coil test assembly comprises a printed circuit board having respective conductors which form the excitation coil winding, the sensing coil winding, the input transformer winding, the output transformer winding and the connections between these respective elements. Pot core type transformers are mounted in close proximity to said windings. The printed transformer windings constitute respectively the secondary winding of the input transformer and the primary winding of the output transformer.