CONTROL METHOD FOR OUTPUT VOLTAGE OF GENERATOR

PROBLEM TO BE SOLVED: To provide a method for controlling the output voltage of an alternating-current generator wherein the output voltage of the generator can be controlled to a specified value only by simply setting the number of the series-connections in a power cable. SOLUTION: A line length switch circuit 12 outputs from the output of an alternating-current generator 11 a supply voltage Vg so set that it is switched from one to another of a plurality of voltages by programming corresponding to the number n of series connections; and line length information Ln corresponding to the number n of series connections in a power cable 20 of a fixed length L. A transformer 14 for measurement outputs a secondary voltage Vb from the supply voltage Vg. A set voltage storage device 17 stores a target voltage Vbn for the secondary voltage Vb corresponding to the number n of series- connections, and outputs a target voltage Vbn corresponding to the linge length information Ln input. A comparing section 18 compares the secondary voltage Vb with the target voltage Vbn, and outputs an offset voltage. An excitation control section 15 and an exciter 16 control the exciting current If to the alternating-current generator 11 so that the offset voltage will be zeroed.