Distance compensation in magnetic probe testing systems wherein object to probe spacing is employed as an exponent in excitings probes or processing probe outputs

摘要

A system is disclosed for nondestructive object testing comprising a magnetic probe responsive to an excitation signal for generating a magnetic field and thereby inducing eddy-currents in the object. The probe further provides an output signal indicative of the presence of a flaw in the object. A distance sensor generates an output signal indicative of the spacing of the probe from the object. Circuitry is provided for receiving the distance sensor output signal and is responsive thereto to supply such excitation signal to the probe. The circuitry employs the distance indication in the distance sensor output signal as an exponent in generating the excitation signal.