| 摘要 |
PURPOSE:To facilitate adjustment of setting of predicted resonance frequency by sequentially lowering the carrier frequency, by a predetermined amount with predetermined interval, based on a command from a frequency operating circuit receiving a frequency lowering command from a vibration detecting circuit upon occurrence of vibration in the motor current. CONSTITUTION:Upon detection of resonance through a detecting circuit 2 during operation, carrier frequency correcting operation is started through a frequency operating circuit 1 based on an output command from the detecting circuit 2. Operating point of carrier frequency fc makes transition such that P1 P2 P3... and the carrier frequency fc lowers sequentially such that fc1 fc2...-fc3... with predetermined interval until resonance ceases. If resonance does not cease even if the carrier frequency fc lowers to the lower limit, the frequency operating circuit 1 provides an inverter operation stop command BS thus stopping operation of an inverter. By such arrangement, adjustment concerning to setting of predicted resonance frequency can be facilitated. |
