Continuous wave eddy current testing is one of several non-destructive testing methods that use the electromagnetism principle. Conventional eddy current testing utilises electromagnetic induction to detect discontinuities in conductive materials.
A specially designed coil energised with alternating current is placed in proximity to the test surface generating changing magnetic-field which interacts with the test-part producing eddy current in the vicinity.
The electrical conductivity variations or magnetic permeability of the test-part, or the presence of any discontinuities, will cause a change in eddy current and a corresponding change in phases and amplitude of the measured current. The changes are shown on a screen for easy interpretation.
Inspection of surfaces at high temperature are possible with the eddy current technique as it is a non-contact method.