| 摘要 |
When a flaw is detected by generating an eddy current in a conductor, even a flaw located in the vicinity of the backside of the conductor is made likely to be detected easily. An exciter and a receiver approach the conductor, a secondary magnetic field is generated by inducing an eddy current in the conductor by a primary magnetic field generated through excitation, and the state of the magnetic field is detected by a receiver. The exciter has a coil and a core. The coil (1) has a first current line and a second current line where the direction of a current is reversed. The core (6) has a gate-shaped cross-section and consists of a first leg, a second leg, and a beam. The core (6) directs the opening on the side opposite to the beam toward the conductor (2) side. The first current line of the coil is arranged on the inside of both legs of the core. The second current line is arranged on the outside of the first leg. Around the first current line, a magnetic circuit passing through the first leg, the beam, the second leg, and the conductor is formed. Around the second current line, a magnetic circuit passing through the first leg and the beam is formed. The receiver (7) is arranged at a corner between the second leg and the conductor on the side opposite to the second current line on the outside of the core. |
