Importance

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Abstract

The present invention is an automatic door operator which includes an obstruction detector for at least stopping the motor when the detected motor speed indicates a motor torque greater than the selected closing torque limit while closing the door, and for at least stopping the motor when the detected motor speed indicates a motor torque greater than the selected opening torque limit while opening the door. The motor speed is detected based upon a predetermined count of electrical pulses corresponding to motor shaft rotation in order smooth noise. Selection of the number of pulses per rotation enables the same controller to control motors operating on either 60 Hz or 50 Hz power. A travel count of rotation pulses permits identification of a plurality of regions in the opening and closing travel of the door and corresponding adaptive torque limits. The travel counter may also be employed for detection of the fully opened and fully closed limits. The controller can be used to control either a four-pole motor or a six-pole motor via a manual motor type selection switch, which selects a torque limit table.

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First Claim