Tangential Eddy Current Array 

TECATangential Eddy Current Array is an array containing coils positioned such that their central axes are aligned parallel to the inspection surface. This enables a directional eddy current distribution that is sensitive to surface-breaking cracks as the eddy current is forced to flow under them, making accurate crack sizing depth estimates possible. This arrangement is less sensitive to lift-off variations than conventional eddy current testing.

TECA is particularly suited for the inspection of ferromagnetic steel. As such, it is considered to be the dry, quantitative replacement for magnetic particle testing (application dependent). Commercial TECA probes typically incorporate spring-loaded elements so they can conform over weld caps with extra lift-off sensors for additional compensation. TECAs have the benefits inherent in arrays: send-receive topologies to enhance defect detection capabilities and significantly larger coverage than single-probe systems.

For more information on TECA see: A Raude et al, ‘Advances in carbon steel weld inspection using tangential eddy current array’, 19th World Conference on NDT, 2016. Available at: www.ndt.net/article/wcndt2016/papers/we2c5.pdf

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