EDDY-CURRENT METHOD OF DOUBLE-FREQUENCY TEST OF ARTICLES Russian patent published in 2002 - IPC

FIELD: non-destructive testing, contact-free measurement of thickness of no-magnetic current-conducting articles. SUBSTANCE: first high-frequency eddy-current converter is placed in oscillatory circuit. Phase difference between high- frequency excitation signal and output signal of first converter is used to adjust frequency of this excitation signal till it corresponds to resonance frequency of oscillatory circuit. Then low-frequency excitation signal is formed with the use of division of frequency of high-frequency excitation signal by even count-down ratio and is fed to second low-frequency eddy-current converter. Count-down ratio is chosen with due account of type of current-conducting coat. Thickness of tested coat is found by results of processing of amplitude-phase values of output voltage of second converter. Stabilization of generalized parameter β is secured by adjustment of operational frequency of second converter. EFFECT: high measurement accuracy. 1 dwg