Thickness Measurement of an Iron Plate Using Low-Frequency Eddy Current Testing With an HTS Coil
| Autor: | Masaaki Matsuo, Teruyoshi Sasayama, Keiji Enpuku, Tomoki Ishida |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Superconductivity Materials science 020208 electrical & electronic engineering 02 engineering and technology Low frequency Condensed Matter Physics 01 natural sciences Finite element method Electronic Optical and Magnetic Materials Inductance Nuclear magnetic resonance Electromagnetic coil Eddy-current testing 0103 physical sciences 0202 electrical engineering electronic engineering information engineering Skin effect sense organs Electrical and Electronic Engineering Composite material skin and connective tissue diseases Electrical impedance |
| Zdroj: | IEEE Transactions on Applied Superconductivity. 26:1-5 |
| ISSN: | 1558-2515 1051-8223 |
| DOI: | 10.1109/tasc.2016.2535366 |
| Popis: | We applied low-frequency eddy current testing (ECT) using a high-temperature superconducting (HTS) coil in order to measure the thickness of an iron plate. Using this method, we measured changes in coil impedance when the iron plate was placed below the coil. Although low-frequency measurements were necessary to avoid the skin effect, changes in coil impedance became very small at low frequencies. For this reason, an HTS coil was used in order to sensitively measure these small changes. First, changes in the inductance L and the resistance R of the coil were measured when the iron plate was positioned 18 mm below the HTS coil, and the thickness of the plate was changed in increments from 6 to 22 mm. The results show that we were able to estimate the thickness of the plate up to 22 mm based on the changes in R when an excitation frequency of 4 Hz was used. Next, the effect of the liftoff between the iron plate and the HTS coil on the changes in Land R was studied while the liftoff was changed from 18 to 28 mm. The results show that the liftoff could be estimated from the changes in L. We were therefore able to determine the liftoff and the thickness of the iron plate by measuring changes in L and R, respectively. Results obtained from numerical simulation using the finite element method were in agreement with the experimental results. |
| Databáze: | OpenAIRE |
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