Technologies
- NDT and Asset Reliability
  - Conventional NDT

Eddy Current Testing

Eddy Current Testing is one of several Non Destructive Testing methods that use the ‘electromagnetism’ principle. Conventional Eddy Current Testing utilised 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. Variations in the changing phases and magnitude of these eddy currents is then monitored through the use of receiver-coil(s), or by measuring changes to the alternate current flowing in the primary excitation-coil. 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. This is the basic principle of eddy current inspection.

Other type of Eddy Current Testing technique in use is the Pulsed Eddy Current Testing. A major advantage of this type of testing is that, there is no need for direct contact with the tested-part. Measurement can be performed through protective coatings, weather sheetings, corrosion products and even the insulation-materials. High temperature inspections are possible with this technique. Compared to the conventional Eddy Current Testing, Pulsed Eddy Current Testing allows multi-frequency operation.