Spring return actuator for a damper

• US 20040212336A1
• Filed: 04/24/2003
• Published: 10/28/2004
• Est. Priority Date: 04/24/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lange, Christopher M., Mrozek, Greg T., McMillan, Scott D.
• Granted Patent: US 6,979,965 B2
• Time in Patent Office: Days
• US Class Current: 318/439
• CPC Class Codes: F16K 31/046 with electric means, e.g. electric switches, to control the motor or to control a clutch between the valve and the motor F16K31/041 takes precedence
• CPC Class Codes: Y10T 137/0318 Processes

Abstract

An actuator including an electric motor driven by a drive circuit powered by a power source, and a load coupled to the electric motor. The actuator further includes a spring biasing the load to a first position, and a microcontroller coupled to the electric motor to commutate the electric motor. Upon failure of the power source, the spring returns the damper to the first position, and, as the spring returns the load to the first position, the electric motor is spun to generate electricity that is used to power the microcontroller. The microcontroller can govern a speed at which the spring returns the load to the first position. In addition, a potentiometer can be used to indicate when the load approaches the first position so that the microcontroller can slow the speed of return prior to the load reaching the first position.

Claims

1. An actuator, comprising:

an electric motor driven by a drive circuit powered by a power source;

a load coupled to the electric motor;

a structure biasing the load to a first position; and

a microcontroller coupled to the electric motor to commutate the electric motor;

wherein the structure returns the load to the first position, and wherein, as the structure returns the load to the first position, the electric motor is spun to generate electricity that powers the microcontroller.

2. The actuator of claim 1, wherein the load is a damper.

3. The actuator of claim 1, wherein the microcontroller governs a speed at which the structure returns the load to the first position.

4. The actuator of claim 3, further comprising a potentiometer to indicate when the load approaches the first position.

5. The actuator of claim 1, wherein the structure returns the load to the first position upon failure of the power source.

6. A spring return actuator for a damper, comprising:

an electric motor driven by a bridge circuit powered by a power source;

at least one sensor positioned to sense rotation of a rotor of the electric motor;

a gear train coupled to a shaft of the electric motor;

a damper coupled to the gear train of the electric motor by an actuator shaft, the damper moving between an open position and a closed position;

a spring biasing the damper to the closed position; and

a microcontroller coupled to the electric motor to commutate the electric motor;

wherein, upon failure of the power source with the damper in the open position, the spring returns the damper to the closed position, and wherein, as the spring returns the damper to the closed position, the electric motor is spun to generate electricity that is used to power the microcontroller, and wherein the microcontroller monitors a speed of return of the damper to the closed position by measuring time intervals between state transitions measured by the sensor, and wherein the microcontroller short circuits the bridge circuit and thereby slows the electric motor and return of the damper to the closed position if the microcontroller determines that the speed has exceeded a given threshold.

7. The spring return actuator of claim 6, further comprising a potentiometer to indicate when the damper approaches the closed position.

8. The spring return actuator of claim 6, wherein the microcontroller slows the electric motor when the damper nears the closed position.

9. A heating, ventilating, and air-conditioning system, comprising:

an electric motor powered by a power source;

a damper coupled to the electric motor, the damper moving between an open position and a closed position;

a spring biasing the damper to the closed position; and

a microcontroller coupled to the electric motor, wherein, upon failure of the power source with the damper in the open position, the spring returns the damper to the closed position, thereby spinning the electric motor to generate electricity to power the microcontroller, and wherein the microcontroller monitors a speed of return of the damper to the closed position and slows the electric motor and return of the damper to the closed position if the microcontroller determines that the speed has exceeded a given threshold.

10. The actuator of claim 9, further comprising a potentiometer to indicate when the load approaches the first position.

11. A method of returning a damper to a closed position, the damper being coupled to an electric motor, and a spring coupled to the electric motor to return the damper to the closed position, the method comprising:

allowing the spring to return the damper to the closed position upon power failure;

measuring a speed of return of the damper to the closed position by monitoring state transitions of sensors of the electric motor;

slowing the speed of return of the electric motor if the speed has exceeded a given threshold.

12. The method of claim 11, further comprising powering a microcontroller using electricity generated by the electric motor being turned by the spring, the microcontroller slowing the speed of return if the speed has exceeded the given threshold.

13. The method of claim 11, wherein the slowing step further comprising short-circuiting the electric motor to slow the speed of return.

14. The method of claim 11, further comprising slowing the speed of return of the electric motor as the damper nears the closed position.

15. An actuator, comprising:

a motor driven by a circuit powered by a power source;

a load coupled to the motor;

a member biasing the load to a first position; and

a controller coupled to the motor to commutate the motor;

wherein the member biases the load into the first position, and wherein, as the member moves the load into the first position, the motor is spun to generate electricity that powers the controller.

16. The actuator of claim 15, wherein the member is a spring.

17. The actuator of claim 15, wherein the load is a damper.

18. The actuator of claim 15, wherein the controller governs a speed at which the member moves the load to the first position.

19. The actuator of claim 15, further comprising a potentiometer to indicate when the load approaches the first position.

20. The actuator of claim 15, wherein the member moves the load to the first position upon failure of the power source.

21. A method of returning a damper to a first position, the damper being coupled to an electric motor of an actuator, the electric motor being adapted to drive the damper from the first position to a second position under control of a controller, the method comprising:

mechanically driving the damper from the second position toward the first position, wherein the motor is spun as the damper is driven toward the first position;

using electricity generated by the motor as the motor is spun to power the controller; and

using the controller to slow a speed at which the damper is mechanically driven toward the first position.

22. The method of claim 21, further comprising allowing the controller to slow the speed at which the damper is mechanically driven toward the first position if the speed exceeds a given threshold.

23. The method of claim 21, further comprising slowing the speed at which the damper is mechanically driven toward the first position when the damper reaches a predetermined position.

24. The method of claim 21, wherein the damper is mechanically driven toward the first position by a spring.