| 摘要 |
PROBLEM TO BE SOLVED: To facilitate adjustment of override for changing a command frequency. SOLUTION: An apparatus has an analog input circuit 24 for inputting analog data for setting the override of a command frequency, an analog-to-digital converter 25 for converting the analog data inputted from this input circuit 24 into a digital value, a storage portion 28a for storing set points of at least three spots and an override ratio at each set point, and a control portion 26a, which finds set points of two spots adjacent to it on the basis of the converted digital value, successively computes an override ratio to be found through linear approximation between these two spots, multiply a command frequency f0 inputted from the outside by this computed override ratio, to find the override of the command frequency, and controls an inverter portion 23.
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