Harmonic analysis of the exciter´s exciting current of a brushless AC generator with a rotary rectifier

The harmonic contents and the waveform of the exciting current of the exciter concern the rotor faults of a brushless AC generator with a rotary rectifier very nearly. The principle of the fast Fourier transformer (FFT) in Matlab is described in this paper. Based on the work of Tian Mingxing et al., the harmonic contents of the exciting current of the exciter is calculated under the normal and fault conditions, and the results are confirmed by the values calculated and measured by Xio Leming (China ship repair, no.3, p.27-9, 1997). However, the present method is more facilely.