Barrier movement operator speed control
AssigneeThe Chamberlain Group, Inc.
InventorsJames J. Fitzgibbon, Robert Keller, Edward Laird
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for controlling the speed of an A.C. induction motor are disclosed and shown in operation for controlling the movement of a barrier. Included are voltage configuration circuits which selectively gate portions of the half-cycles of AC mains voltage to the induction motor. When the motor is started increasing amounts of mains AC voltage is applied to the motor and decreasing portions of the mains AC are applied to the motor during a stopping routine. The motor can also be energized with less than full mains AC to permit differences in barrier movement speed dependent on operating parameters.
Claims36
A barrier movement operator comprising:
- an A.C. induction motor coupled to the barrier for controlling the movement of the barrier;
- a source of mains A.C. operating voltage comprising a frequency;
- a motor control apparatus connected to the main operating voltage and the induction motor and responsive to power control signals from a controller for varying the effective frequency of the mains operating voltage coupled to the induction motor;
- and
- the controller responds to user commands and detected conditions of the barrier for incrementally changing a speed of movement of the barrier by generating power control signals to control the motor control;
- wherein the motor control apparatus operates in synchronism with the frequency of the mains A.C. voltage for varying the effective percentage of line voltage and sub harmonics of the mains A.C. voltage applied to the motor.
An A.C. induction motor control apparatus comprising:
- an A.C. induction motor;
- a source of mains A.C. operating voltage comprising a frequency;
- a motor control circuit connected to the mains voltage and the induction motor and responsive to power control signals from a controller for varying the effective frequency of the mains operating voltage coupled to the induction motor;
- and
- the controller includes a program for incrementally changing a rotational speed of the induction motor by generating power control signals to control the motor control circuit;
- wherein the motor control circuit operates in synchronism with the frequency of the mains A.C. voltage for varying the effective percentage of line voltage and sub harmonics of the mains A.C. voltage applied to the motor.
An A.C. induction motor control apparatus comprising:
- an A.C. induction motor;
- a source of mains A.C. operating voltage comprising a frequency;
- a motor control circuit connected to the mains voltage and the induction motor and responsive to power control signals from a controller for varying the effective percentage of the mains voltage and sub-harmonics thereof coupled to the induction motor;
- and
- the controller includes a program for incrementally changing the speed of the induction motor by generating power control signals to control the motor control circuit.
Dependencies are inferred from the claim text.