| 摘要 |
A uniform voltage is applied to loads even to other than a multiple of three loads made of heating lamps connected in parallel to each other, without causing any burden on a primary side. The number of loads is divided into a multiple of three and a multiple of two. A three-phase AC voltage is applied to three primary windings, which are connected as a Y-connection or a &Dgr;-connection. Secondary windings, which are each magnetically coupled to a primary winding of a plurality of three-phase transformers and have the same number of turns, are connected with the multiple of three loads. The number of turns of the M-seat primary winding of a Scott transformer is divided into two at a midpoint, to which an end of the T-seat primary winding having a number of turns equal to (√3)/2 times that of the M-seat primary winding, is connected and to which the three-phase AC voltage is applied. The M-seat primary winding and the T-seat primary winding in at least one Scott transformers are each magnetically coupled with each of the secondary windings having the same number of turns. The multiple of two loads are connected to the secondary windings so that no secondary windings appear without a load connected thereto. Thus, an AC voltage can be uniformly applied to the heating lamps without increasing any burden on the primary side. |
