| 摘要 |
<p>A drive assembly 10 for a power operated door comprises a DC motor 12 which is drivingly coupled to a torsion spring shaft assembly 13 of the door. The motor is controlled by a control circuit which includes a current sensing device and a microcontroller, the current sensing device causing disabling of the motor when a higher than expected current is sensed which is indicative of the fact that either the door has reached its fully opened or closed positions or has encountered an obstruction. The control circuit may comprise a MOSFET connected to a monitoring circuit which monitors the flow of current through the MOSFET. The drive assembly 10 may be powered via a backup DC power supply which is charged by an AC supply through a transformer. <IMAGE></p> |
