PROCESS OF EDDY-CURRENT INSPECTION AND DEVICE FOR ITS EMBODIMENT Russian patent published in 2002 - IPC

FIELD: instrumentation, test of linear and angular displacement, of vibration value of current-conductive objects. SUBSTANCE: eddy- current converter in the form of parallel oscillatory circuit which is periodically connected to source of direct stable current with the help of first switching element to form inherent decaying oscillations in circuit is used in process. Half-cycle with maximum change of amplitude of decaying oscillations caused by change of parameters of inspected object is utilized as informative parameter. Change of amplitude is recorded by means of detector and retrieval-storage device connected in series. Measurement error caused by effect of environmental temperature on resistance of coil of eddy-current converter is compensated with the use of second retrieval- storage device, voltage amplifier and third switching element connected in series. Drop of voltage across resistance of coil is measured prior to switching off source of current from eddy-current converter. After source of current is switched off from eddy-current converter output value of source of current is restored to initial value. EFFECT: enhanced sensitivity, speed of inspection and reduced measurement error. 4 cl, 9 dwg