| 摘要 |
A linear induction motor for automatically operating a reciprocating member or door incorporating a control system for the motor by which the door is accelerated at full thrust to travelling speed, means for reducing the motor thrust to enable the door to coast at approximately constant speed until reaching a limit switch which initiates reverse thrust braking, with means to automatically cut out the braking as soon as the door has stopped and means for driving the door at low thrust to a final limit switch, an overspeed relay for initiating the reversal of the motor thrust when the door speed exceeds a predetermined value. |
