| 摘要 |
PURPOSE:To positively correct D.C. field distortion produced in a transformer, by a method wherein current of second harmonic component to the power source frequency contained in exciting current flowing in a primary winding is detected by a current transformer and a band-pass filter, and output in a variable D.C. source is adjusted to make the current zero. CONSTITUTION:If exciting currents iU, iV, iW are detected at current transformers 3U, 3V, 3W and passed through band-pass filters 4U, 4V, 4W, output signals corresponding to D.C. field distortion amount are obtained in output side of the band-pass filters 4U, 4V, 4W. Variable D.C. power sources 5U, 5V, 5W receive the output signals of the band-pass filters and adjust respective outputs for these signals to become zero and supply D.C. currents to auxiliary windings 6U, 6V, 6W. D.C. field distortion existing in a transformer winding 1 is corrected to zero by D.C. currents supplied to the auxiliary windings 6U, 6V, 6W. |
