Hitachi, Ltd.

Ryozi Nakatake

Yoshitake Kashima

Teruo Fukuda

Low, middle and high voltage windings are wound on a magnetic core in this order, the high voltage winding having a high voltage line terminal at its center and neutral terminals at both ends. Two middle voltage partial windings are coaxially wound on the outside of the high voltage winding at upper and lower positions separated by a necessary distance for insulation. One end of each of the middle voltage partial windings are connected to the neutral point of the middle voltage winding, and the other ends thereof are each connected to the respective tap windings of two tap changers. Thus, the middle voltage partial windings and the tap changers constitute a parallel circuit in which a circulating current flows thereby to induce magnetic flux in each of the middle voltage partial windings and tap windings. The middle voltage partial windings and tap windings are so wound that the magnetic coupling therebetween through the induced magnetic flux can be reduced.

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Hitachi, Japan

Ryozi Nakatake