[1] RFT is also referred to as remote field eddy current testing (RFEC or RFET).
Although RFT works in nonferromagnetic materials such as copper and brass, its sister technology eddy-current testing is preferred.
The exciter coil is pumped with an AC current and emits a magnetic field.
The main differences between RFT and conventional eddy-current testing (ECT) is in the coil-to-coil spacing.
The RFT probe has widely spaced coils to pick up the through-transmission field.