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

FIELD: non-destructive test of quality of materials and articles. SUBSTANCE: eddy-current method can be utilized to measure thickness of non-magnetic coats with compensation of effect of clearance between eddy-current converter and surface of article or to measure thickness of dielectric coats independent of variation of electromagnetic properties of base. Prior to measurement of amplitude of output signals of eddy-current converter it is first set in oscillatory condition by connection to resonance circuit. Resonance frequency is set equal to frequency of supply current. Measured amplitude is compared with level recorded in advance. Amplitude of pulses of excitation current is adjusted depending on obtained signal of misbalance. Signal of misbalance and phase of output signal of eddy-current converter are used to determine parameters of tested article. Adjustment of amplitude of pulses of excitation current allows instrument error in measurement of phase of output signal of eddy-current converter to be reduced. EFFECT: reduced instrument error. 1 dwg