| 摘要 |
PURPOSE:To suppress current oscillation when a crane is driven. CONSTITUTION:A driver for crane employing a V/F control inverter 2 is equipped with an oscillation detector 5 for detecting the periodical variation of current of a motor M for driving the crane. An electromagnetic brake Br for the crane driver generates brake force based on an oscillation current detection signal delivered from the detector 5 and increases the load torque of the motor M temporarily. Consequently, slip of the motor is increased and the oscillation of current is suppressed. The current oscillation is suppressed positively by detecting the oscillation current of the driving motor M, generating the brake force from the electromagnetic brake Br based on the detection signal and temporarily increasing the load torque of the motor M thereby increasing the slip of the motor M. |
