| 摘要 |
<p>An electronic control system for an electric motor driven mechanism having two opposing extremes of travel, such as a garage door, where a signal to the motor to open the door is initiated and sustained in operation by a first circuit Q1 and to close the door is initiated by a second circuit Q3 but sustained in operation by a third circuit Q2. Since all circuit states are determined by an alternate-action switch 51a-51c common to all three circuits plus two normal limit switches 52, 53 and a set-reset flip-flop IC1c-IC1d, an opening door can be stopped and started at will or by unlimited types of override sensor switches, or when closing can be reversed to run open at will or by unlimited override switches. If stopped by an override switch the motor will not restart until commanded to. The motor may be a series type motor or an induction motor. <IMAGE></p> |
