| 摘要 |
PURPOSE:To prevent a load motor from breaking down to occur when the frequency decreases by setting output voltage vs. output frequency characteristic at frequency rising and falling time in response to a load characteristic. CONSTITUTION:A microcomputer 10 judges to control to rise or fall a frequency, outputs the judged result as a direction judgement signal R, and outputs a frequency signal Q to a sequential controller 11. A changeover switch 14 is switched by the signal R from the microcomputer 10 to a voltage setter 12 side under the rising control, and to a voltage setter 13 under the falling control. Suitable UP and DOWN characteristics are applied in accordance with the frequency control direction to prevent a motor from breaking down irrespective of the load characteristic and a variation in a power source. |
