Motor-driven curtain assembly and motor control device therefor

A motor-control device for a motor-driven curtain assembly that includes a longitudinally extending hollow top rail, a longitudinally extending drive shaft mounted rotatably in the top rail, a motor for driving rotatably the drive shaft, and a curtain unit coupled to the drive shaft such that rotation of the drive shaft in a positive direction results in movement of the curtain unit to a closed position, and such that rotation of the drive shaft in a negative direction results in movement of the curtain unit to an open position, said motor-control device comprising:

• a driving circuit adapted to be coupled to the motor and adapted to enable rotation of the motor in the positive and negative directions;
• a control unit coupled to said driving circuit and operable so as to control said driving circuit to enable rotation of the motor in a selected one of the positive and negative directions;
• a current limiting circuit adapted to couple said driving circuit to an external power source, and adapted to limit current flow from the external power source to said driving circuit when the motor is subjected to an increase in load resistance;
• and
• an overload detector, coupled to said control unit and said current limiting circuit, for generating a control signal that is indicative of the amount of current flowing from said current limiting circuit to said driving circuit and that is provided to said control unit, thereby enabling said control unit to deactivate said driving circuit for stopping operation of the motor when overloading of the motor occurs.