Affiliations: [a] Nuclear Professional School, School of Engineering,
The University of Tokyo, 2-22 Shirane Shirakata, Tokai, Naka, Ibaraki 319-1188,
Japan. Tel.: +81 29 287 8431; Fax: +81 29 287 8488; E-mail: {demachi,
rybalko, yusa}@tokai.t.u-tokyo.ac.jp
Abstract: This paper proposes the method to detect and diagnose the defects of
the rotating wings of turbines, pumps and motors by the measuring the change of
the eddy currents comparing with those of no defects. The eddy current is
induced in the conductor wings rotating in the static magnetic field and the
magnetic field by the eddy current is measured by a pick-up coil. The magnetic
field are obviously different between the wings with/without the defects. This
method has the possibility of contribution to the earlier findings of the
defects of the abnormality of the turbines, pumps and motors. Moreover, the
time-series of the horizontal displacement of the rotating axis was measured by
the laser displacement meter. To the axis, the external magnetic force was
applied by a ring magnet to make the unstable state. The SSA (Singular Spectrum
Analysis) [2] was applied to analyze the time-series of the displacement
in the unstable state and it was shown that some of the SSA components are
sensitive enough for the earlier detection of the transition to the unstable
state.
