| 摘要 |
PURPOSE:To suppress the heating and burnout of an inverter device by using a high voltage pattern when a motor is started and automatically switching it to a low voltage and using after the motor reaches rated rotating speed range thereby accelerating the rise of the motor. CONSTITUTION:A logic pattern control signal is stored in an ROM28 to obtain an output voltage which is maintained at the prescribed ratio to the set frequency. A speed setting circuit 15 sets the output frequency of an inverter. A voltage ratio setting circuit 19 sets the ratio of the first to second output voltages. The first and second signal deciding circuits 20, 21 decide the first and second speed set signal based on the signals from the circuit 15 and 19. The content of an ROM28 responsive to the first set signal is read out when the motor is started, and when the motor reaches the prescribed rotating speed, the content of the ROM28 responsive to the second set signal is read out when the motor reaches the prescribed rotating speed range. |
