When an alternating current is applied to a conductor, such as copper wire, a magnetic field develops in and around the conductor. This magnetic field expands as the alternating current rises to a maximum and then collapses to zero. If another electrical conductor is brought into close proximity to this changing magnetic field, current will be induced in this second conductor. Eddy currents are induced electrical currents that flow in a circular path.
The association with electricity and magnetism give this NDT method a history unmatched in Non-Destructive Testing. Whether it was Democritus in 400BC, or Benjamin Franklin in the 1700’s, trying to wrap their heads around the theory of electromagnetic induction, or Maxwell’s work “A Treatise on Electricity and Magnetism”, written in 1873. Scientists have continued to develop and refine this theory for more than two millennia.
Today’s eddy current testing has made advances that are light years ahead of even where the technology was a decade ago. Whether the standard is speed, resolution, frequency selection, filters,or mix suppression, these enhancements have improved the reliability, and accuracy, of the eddy current test.
Training and Personnel
Training is essential to a good eddy current test. The ability to draw on thousands of analysis man hours, and physical analysis of defective parts, is the most important way to ensure your inspections are worth the costs. None of the eddy current equipment improvements will mean anything if your technicians don’t have the experience and training to make the correct call. If the personnel performing the test can’t differentiate between a damage mechanism and a benign anomaly your critical inspections will become suspect. NDE Technology provides this level of expertise. All our technicians meet, or exceed all of the many code requirements, required in today' nuclear, fossil, and aerospace industries.