| 摘要 |
A door (A) is driven by a motor (B) having a control circuit with: (a) speed control using a motor-speed sensor (C) providing a rectified (D) signal that is compared (E) with a reference (F): a power-control circuit (G) is thereby controlled to maintain door speed against e.g. wind resistance; and (b) overload protection using a converting circuit (I) responsive to a voltage variation from the power-control circuit (G) to derive an overload signal that is compared (J) with a reference (K), to indicate e.g. the door being blocked, whereupon a control circuit (M) is caused to open the door. <IMAGE> |
