Affiliations: [a] Graduate School of Electrical and Electronics Engineering, Hosei University, Tokyo, Japan | [b] Technical University of Sofia, Sofia, Bulgaria | [c] EMIC (Denshijiki Industry) Co, Ltd, Tokyo, Japan
Correspondence:
[*]
Corresponding author: Takahiro Hyuga, c/o Y.Saito Lab. of The Graduate School of Electrical Engineering, Hosei University, 3-7-2 Kajinocho, Koganei, Tokyo 184-8584, Japan. E-mail:takahiro.hyuga.8k@stu.hosei.ac.jp
Abstract: Previously we have succeeded in exploiting a new high
sensibility eddy current testing (ECT) sensor called the infinite (∞)
coil. Operating principle of this ∞ coil is that two adjacent
coils constructing the north and south poles alternatively set a zero
magnetic potential region and keep the same situation when eddy currents are
flowing along the paths in parallel to the exciting coils. If the eddy
currents could not flow the paths in parallel to the exciting coil on the
test specimen, then a zero magnetic potential region between the two
exciting coil moves toward the other position. This means that a sensing
coil located at a mid position of two exciting coil is possible to detect
the disturbed magnetic fields, i.e., the defect in the test specimen could
be detected from the sensing coil signal. In the present paper,
consideration of the practical flat/film ∞ coil design leads to an
employment of the two rectangular shape exciting coils. Practical
experiments and 3D FEM simulations verify the validity of our practical
design policy of the flat/film ∞ coil.
Keywords: Nondestructive testing, ECT, practical design, enhancement of sensor
