| 摘要 |
PURPOSE:To smoothly vary the frequency of an inverter by varying the detection level of an output current detector in response to the output frequency of the inverter, thereby preventing useless level rise in a frequency varying state. CONSTITUTION:An output current detector 3 has a current sensor 4, and a level detector 5 having a low level detector 51, a high level detector 52. When the output frequency of the inverter 1 is in a constant state, the detection output of the detector 51 is inputted, and when the output frequency of the inverter 1 is in a varying state, the detection output of the detector 52 is inputted to a timer 6. The timer 6 decreases the output frequency and the voltage of the inverter 1 by the output of the detector 5 after the prescribed time. |
