抄録
The presence of stator current harmonics from static frequency converter starter operation results in the induction of currents of various magnitudes and frequencies on the surface of the rotor. These eddy currents flow in series-parallel paths comprised of rotor iron, rotor wedges, damper bars and retaining rings and distribute according to the impedance of the paths. If the plural rotor wedges retain field coils in one slot, the eddy current paths are complicated further. This paper describes turbine generator rotor eddy currents and losses for a static frequency converter starting. To consider air parts between a rotor wedge and the adjoining wedge, the currents are calculated by three-dimensional numerical magnetic field analysis. The results are as follows.
(1) The eddy currents flow mainly in the wedge.
(2) If there are the damper bars, the eddy currents concentrate in the damper bars between two adjoining wedges.
(3) If there is no damper bar, the eddy currents concentrate in the rotor tooth between two adjoining wedges.
