Abstract: Apparatus for non-destructive examination of a plate for defects existing in one of both of opposed first and second surfaces thereof includes a rotatable support platform, an eddy current coil structure for inducing eddy currrents in the plate located at a first location in the platform, a first magnetic flux generator disposed at a second location in the platform, the second location being opposite the first location on a line extending from the first location through the platform center. A drive unit rotates the platform relative to the plate.

Abstract: A method for nondestructive examination of an object of type having localized permeability variations therein and varying surface conditions and grain structures comprises the steps of AC flux saturating a localized surface area of the object so as to magnetically saturate the surface area to quiet localized permeability variations therein and to set up a stabilized high level primary field on the surface substantially unalterable by the varying surface conditions and grain structures in the object and detecting eddy currents in the surface area. Coil structure and apparatus for implementing the method are also defined. Further, the method is disclosed as being implemented in part by the use of components of a pre-existing object evaluation device.

Abstract: A system for processing signals produced by magnetic flaw detection apparatus having facility for examining objects in the course of transport thereof at speeds varying from a prescribed slow speed to a prescribed high speed, with transport frequency thus being within a first frequency range. The system comprises first circuitry for detecting the speed of transport of an object under examination and generating output signals indicative of the detected speed and extending over a given characteristic range correspondingly with the first frequency range. Second circuitry is provided for receiving the first circuitry output signals and transforming the same into a second frequency range substantially expanded as compared to the first frequency range.

Abstract: Non-destructive testing apparatus for rollers and the like of magnetic material comprises a pair of rotating spin rails having intermediate sections of magnetic material. Feeding apparatus deposits rollers on the spin rails and moves them successively past the magnetic sections. A magnet produces flux through the magnetic sections and a roller rotating thereon. Variable reluctance sensing apparatus senses changes in the flux. An eddy current test probe is positioned adjacent the magnetic sections. Variable reluctance and eddy current test circuits produce flaw output signals which control apparatus for segregating the rollers. Advantageously the feeding apparatus intermittently deposits successive rollers on the spin rails and intermittently moves the rollers along the rails in end-to-end relationship.