| 摘要 |
PURPOSE:To conduct constant-speed operation at free speed by changing over a slip-frequency signal to a slip-frequency signal corresponding to a difference between a constant-speed command signal and a speed signal when a constant- speed operation command is transmitted. CONSTITUTION:A fS pattern generator 7 and an IM pattern generator 8 each output a slip frequency pattern fSP1 and a motor current command IMP1 corresponding to the positions of notches for a master controller 6. A fS correction signal fSP corresponding to a difference between a motor current command IMP and a motor current IM and the slip frequency pattern fSP1 are added, and a slip frequency command fS is outputted. When the master controller 6 is closed to a constant-speed operation position, changeover switches 9 and 10 are changed over, and a slip frequency signal fSP2 corresponding to a difference between a speed command signal fP and a speed signal fr and a current command signal IMP2 are outputted. |
