Eddy Current Array Testing

Eddy Current Array (ECA) is a type of nondestructive eddy current testing that involves operating eddy current coils in a probe assembly electronically. Each coil in the probe generates a signal whose strength is determined by the phase and amplitude of the item it is placed over. The data from this signal can be captured and measured. This information can then be linked to an encoded position and time, and visualised as a C-scan image.
Eddy current inspections are a type of non-destructive testing that uses the electromagnetic induction concept. When alternating current is delivered to a conductor, such as an eddy current probe, a magnetic field forms around it that varies in strength as the current alternates. A current will be induced in another conductor, in this case the material being tested, if it is brought close to the initial field. If this material has any faults, the eddy current that emanates from it will be warped.

ECA is capable of reproducing the flaw detection techniques of most other eddy current methods. This method though had several distinct advantages such as:

• Being able to scan a larger area at one time while maintaining a high resolution,

• A lesser need for complex robotics to actually move the probe,

• Improved flaw detection due to the C-scan imaging, and

• Complex shapes can be inspected using this method because the probes can be customized to the profile of the part being inspected.

This method is widely used for a number of industry applications. It can be used both measuring the thickness of steels and detecting corrosion. ECA can be used on materials as diverse as vessels, columns, storage tanks & spheres, piping systems, and even structural applications.