Abstract: An improved polar coordinates sensor comprising a pot-core half having a concentric winding window surrounded by a washer-like high conductive Lenz lens. A toroidal core stack concentrically disposed at the base end of the pot-core half, the pot-core half, Lenz lens and the toroidal core stack being disposed coaxially with aligned winding windows. X-y coordinates excitation winding distributions being shuttled through the coaxial aligned windows to encircle the cross-section of pot-core half, Lenz lens and toroidal core stack forming a series circuit. X-y excitation currents being connected to the excitation distributions to induce a hemispherical driving field. The inductive reactance of the series coupled toroidal core stack allows an increased degree of differential redistribution of driving flux in response to probe tilt. A rotating/non-rotating excitation method, of which a source of the x-y signals may include electromechanical resolver type waveforms.

Abstract: An axial direction groove is formed in a high permeability toroidal core taking the form of a pot core half with a mounting hole, a high cross-section ratio copper casing being tightly fit around core circumference, having poly-phase excitation windings shuttled through the mounting hole to encompass both the copper casing and the pot-core, forming an integral driving-sensing eddy current probe. A naked pot-core is wound as an integral driving-sensing probe. Poly-phase excitation of the probe is mesh-connected as a gramme-ring.

Abstract: An axial direction groove is formed in a high permeability toroidal core taking the form of a pot core half with a mounting hole, a high cross-section ratio copper casing being tightly fit around core circumference, having poly-phase excitation windings shuttled thriugh the mounting hole to encompass both the copper casing and the pot-core, forming an integral driving-sensing eddy current probe. A naked pot-core is wound as an integral driving-sensing probe. Poly-phase excitation of the probe is mesh-connected as a gramme-ring.

Abstract: Oscillatory signal build-up is increased in the polar coordinates sensor by integrating the rotating driving flux with the resonating flux resulting from the series resonant pick-up coil current. The imbalance flux linking the pick-up coil is more dependent on radii proximate the z-axis and is more suitable for detection of cracks radial to an aircraft rivet.

Abstract: Poly-phase induction motor-stator rotating magnetic fields are utilized as driving cores coupled to polar coordinate sensors for higher driving flux utilization and size reduction. External internal and combinational driving core structures are disclosed. An unsegmented stator having an extended longitudinal coupling portion is also disclosed.