| 摘要 |
A tap changer for switching the load current of a transformer from a first winding output to a second winding output includes two pairs of anti-parallel connected semi-conductor rectifiers with a control device for each pair. A switch arrangement is provided for connecting each of the pairs between any of the outputs and a load current connection. The device includes a control arrangement for controlling and performing the switch between the outputs, which includes a device for transmitting the load current from the rectifier pair connected to one winding output to the pair connected to an adjacent winding output. This transfer is carried out partly by natural commutation except when there is a decrease in the turns of the winding and at the same time a resistive load and partly by means of switching when the load current passes through zero upon a decrease in the turns of the winding and at the same time a resistive load.
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