| 摘要 |
An air-conditioner in which the harmonics of when the maximum consumption current is flowing are effectively reduced. A three-phase AC power supply voltage is full-wave rectified by a main rectifier circuit (22). The output is converted into an AC of variable frequency by an inverter (24) so as to drive a motor (25) at variable rotational speed. For the above purpose, the air- conditioner comprises a transformer (10) for outputting a three-phase AC voltage the phase of which leads that of the three-phase AC power supply voltage and a three-phase AC voltage the phase of which lags behind that of the three-phase AC power supply voltage and two auxiliary rectifier circuits (11, 12) for full-wave rectifying the three-phase AC voltages outputted from the transformer and supplying them to the output of the main rectifier circuit. The transformer (10) satisfies a hexagon transformer vector diagram drawn in the following way. A three-phase AC voltage is expressed as a regular triangle vector diagram. A circular arc having its center at each vertex of the regular triangle and connecting the other two vertexes of the regular triangle is drawn, a straight line through the two points dividing each circular arc into three equal segments is drawn, an outside straight line outside and parallel to the above straight line a predetermined distance away from the above straight line is drawn. Similarly, two other outside straight lines are drawn. Straight lines through the three vertexes of the regular triangle are drawn.
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