| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the long-term continuation of the totally closed state of an acceleration/deceleration valve. SOLUTION: An adder 5a performs input to a switching means 12 along with a rated frequency setting signal or a generator frequency signal (s) as a target frequency signal ff, where a bias signal (g) is added to a system frequency signal (f). The switching means 12 performs switching so that the target frequency setting signal ff can be outputted via a contact 12b when an LSM(line speed machine) is on. A down-direction rate limiter 13 limits an output signal (t) with a change rate in a specific down direction via the contact 12b during speed-alignment control, outputs the signal as a target frequency signal (u), and gradually decreases a load setting value signal (b) even if the system frequency signal (f) is extremely lower than a generator frequency signal (h).</p> |
