| 摘要 |
PURPOSE:To protect power elements in a motor drive circuit from breakdown by turning the motor drive circuit off for a predetermined time upon provision of a rotary direction switching command to a forward/reverse circuit incorporated in a control means. CONSTITUTION:A D flipflop 52 delays output Q from a D flipflop 51 by one clock period while a D flipflop 53 delays output Q from the D flipflop 52 by one clock period. A three-phase full-wave logic circuit 36 is provided with output Q from the flipflop 52 as an F/R switching signal. Consequently, before and after switching of the three-phase full-wave logic circuit 36 between forward and reverse rotations, a motor drive circuit is turned off for one clock period respective (total two clock periods) thus fully disabling respective power elements in the motor drive circuit primarily and temporarily. |
