Patent ID: 6580267
Filing Date: 2003-06-17
Classification: G01N,G01V

Abstract:
A method of extending utility;in a toroidal plane sensing face eddy current probe for detecting a flaw in a conducting workpiece by means of detecting an asymmetry in a rotating hemispherical driving field, said probe comprising: a torus core formed of a high permeability material having a poloidal coil space, and; said torus core further formed with an annular groove extending axially from the poloidal coil space to the core surface, said core taking the shape of a pot-core half, and; poly-phase excitation winding distributions wound through the toroid window to symmetrically cover the core surface; ramping poly-phase excitation currents being applied to the said excitation winding distributions for inducing a rotating driving dipole, fringing from the toroidal plane, for inducing a hemispherical eddy current pattern in said workpiece; a poloidal coil being wound concentrically within the said poloidal coil space, and having connecting leads; the said method of extending probe utility comprising: utilization of the said poloidal coil as a pick-up coil as the said means for detecting an asymmetry in the rotating hemispherical driving field; said pick-up coil shunted by a variable capacitor to form an oscillatory tank circuit for building up a flaw signal.