| 摘要 |
<p>PROBLEM TO BE SOLVED: To reset a frequency converter quickly and stably. SOLUTION: A frequency-converter control part 8A, to which a protective- device operating signal (a) expressing the short-circuit protective operation of an overvoltage protective device 5 is input, holds a stop signal (c) used to stop a frequency converter 4 so as to be output to the frequency converter 4. On the other hand, the frequency-converter control part, to which an operation permission signal (b) is input, releases the holding operation of the stop signal (c). A sequence control part 9A is provided with a timing judgment means by which a short-circuit release signal (d) used to release the short-circuit protective operation of the overvoltage protective device 5 and the operation permission signal (b) are output when a state which can stably control the frequency converter 4 is judged according to the magnitude of a short-circuit current signal as its correspondent signal flowing to the overvoltage protective device 5.</p> |
