| 摘要 |
PURPOSE:To provide a small size single phase auto-transformer in which the tertiary voltage does not change by the position of the tap winding and has a small zero phase impedance and a small installation area by providing a first and second iron core legs on the same iron core. CONSTITUTION:As a zero phase circuit there are two circuits, a tertiary winding 3 and a stabilizing winding 8. The zero phase circuit by tertiary winding 8 has no change from the conventional circuits and has a large zero phase impedance. On the other hand, since the stabilizing winding 8 is provided on the main leg 91 of single phase three-leg iron core, the induced voltage per one turn is two times the induced voltage when it is provided on the side leg 92. The zero phase impedance by the stabilizing winding 8 is smaller compared with tertiary winding 3. This can be interpreted that, since the zero phase impedance as seen from high voltage terminal U or medium voltage terminal (u) is the parallel circuit of the stabilizing winding 8 with small impedance and a tertiary winding 3 with large impedance, it is almost determined by the stabilizing winding 8 with small impedance. Accordingly since the stabilizing circuit is not connected to load, its capacity can be small, and the winding on the main leg 91 of a single phase three-leg iron core gives little effect to the size of transformer. |
