Eddy current detection is to put the conductor close to the coil with alternating current (probe for short), by the coil to establish an alternating magnetic field, the alternating magnetic field through the conductor, and electromagnetic induction with it, to establish eddy currents in the conductor. The eddy currents in the conductor also generate their own magnetic field, which also changes the strength of the original magnetic field, resulting in changes in coil voltage and impedance. So when the conductor surface or near surface defects or measurement of metal material changes, will affect the intensity and distribution of eddy current, and caused by changes in eddy current testing coil voltage and the change of impedance, according to the change, can indirectly knew of conductors defects if there is a change and the performance of metal materials.
|Mechanical and electrical stability||Percentage of errors: <0.01%|
|Measuring instrument stability||Percentage of errors: <0.01%|
Instrument accuracy stability
|After 8 hours, ≤2dB|
|Signal to noise ratio||≥ 10dB|
|The rate of false positives||≤1%|