Electric motor with integrally packaged day/night controller

• US 5,457,373 A
• Filed: 09/24/1993
• Issued: 10/10/1995
• Est. Priority Date: 09/24/1993
• Status: Expired due to Fees

• Current Assignee: A. O. Smith Corporation
• Original Assignee: Magnetek Century Electric, Inc.
• Inventors: Heppe, Richard A., Horner, George W.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Masih, Karen
• Application Number:
  US08/126,338
• Time in Patent Office: 746 Days
• Field of Search: 318/772, 388/800, 388/909, 388/933, 388/934
• US Class Current: 318/772
• CPC Class Codes: H02K 11/22 Optical devices
• CPC Class Codes: H02P 25/18 with arrangements for switching the windings, e.g. with mechanical switches or relays
• CPC Class Codes: Y10S 388/909 Monitoring means
• CPC Class Codes: Y10S 388/933 Radiant energy responsive device
• CPC Class Codes: Y10S 388/934 Thermal condition

Abstract

An AC motor is provided with a motor housing and a photoelectric sensor associated with the housing. The sensor is part of a motor control circuit which is thereby responsive to the ambient light condition to control the motor by selectively switching At on and off, or alternatively by selectively switching between higher and lower speeds. The control circuit derives its power from the motor'"'"'s AC input terminals, thereby yielding a self-contained motor control unit, which requires no timer unit and no wiring or mounting by the user. In accordance with another aspect of the present invention, the photoelectric sensor extends through an aperture in a motor housing end cap with the associated control circuitry fitable within the end cap, thereby providing a retrofit for existing motors.

Claims

1. An electric motor comprising:

(A) an electric motor having AC power terminal means for coupling the motor to a source of electric power;

(B) motor housing means having an interior surface and an exterior surface, the interior surface of the housing means generally encompassing the motor and the AC power terminal means;

(C) switching circuit means affixed to a surface of the motor housing means and electrically coupled for power to the AC power terminal means within the motor housing means, the switching circuit means being responsive to a switching signal for selectively switching the motor between one of two speeds;

(D) photosensor means affixed to the motor housing means and positioned to generate the switching signal to the switching circuit means in response to the amount of light incident on at least a portion of the housing means,

whereby the motor is switched between daytime and nighttime speeds in response to ambient light.

2. The electric motor of claim 1 wherein the motor housing means includes an aperture communicating between its interior and exterior surfaces, and

wherein the photosensing means includes photosensing transistor means positioned within the aperture to sense light exterior to the housing means.

3. The motor of claim 2 wherein the switching circuit means is within the interior of the motor housing means.

4. The electric motor of claim 1 wherein the switching circuit means includes delay means for inhibiting the switching between daytime and nighttime speeds until the sensed change in incident light has persisted for a pre-selected period of time.

5. The electric motor of claim 4 wherein the delay means includes adjustment means for varying the required time for persistence of the sensed lighting change.

6. The electric motor of claim 5 wherein the adjustment means is affixed to the motor housing, and positioned to be accessible without the use of tools.

7. A motor control assembly for converting to daylight-responsive operation an electric motor disposed within a housing having an end cap, the motor including AC power terminals within the housing, said assembly comprising:

(A) retrofit end cap means having an interior surface and an exterior surface, the interior surface of the retrofit end cap means being adapted to generally encompass at least a portion of an electric motor disposed within the housing;

(B) switching circuit means affixed to the retrofit end cap means and adapted to be electrically coupled for power to the AC power terminal means, the switching circuit means being responsive to a switching signal for selectively switching the motor between one of two speeds;

(C) photosensor means affixed to the retrofit end cap means and positioned to generate the switching signal to the switching circuit means in response to the amount of light incident on the exterior surface of the retrofit end cap means.

8. The electric motor of claim 7 wherein the retrofit end cap means includes an aperture communicating between its interior and exterior surfaces, and

wherein the photosensing means includes photosensing transistor means positioned within the aperture to sense light exterior to the retrofit end cap means.

9. The motor of claim 8 wherein the switching circuit means is within the interior of the retrofit end cap means.

10. The electric motor of claim 7 wherein the switching circuit means includes delay means for inhibiting the switching between daytime and nighttime speeds until the sensed change in incident light has persisted for a pre-selected period of time.

11. The electric motor of claim 10 wherein the delay means includes adjustment means for varying the required time for persistence of the sensed lighting change.

12. The electric motor of claim 11 wherein the adjustment means is affixed to the retrofit end cap means, and positioned to be accessible without the use of tools.

13. An AC motor adapted to be connected to a source of AC power, and comprising:

(A) a motor housing encompassing the AC motor, the motor housing having an interior surface and an exterior surface and an aperture communicating between the interior and exterior surfaces;

(B) DC power source means within the motor housing and coupled to the AC power source for power;

(C) normally-open relay contact means within the motor housing responsive to a control signal to undergo a state change from open-circuit to closed-circuit condition;

(D) a motor field winding within the motor housing coupled in electrical series with the normally-open relay contact means to the AC power source;

(E) relay coil means within the motor housing and electrically coupled to the DC power source;

(F) switching circuit means mounted to a surface of the motor housing and coupled for power to the DC power source means to selectively energize the relay coil means so as to cause a state change in the normally-open relay contact means,

the switching circuit means including photosensing means mounted within the housing aperture to sense the light level at the exterior surface of the housing so that the relay coil is energized when the photosensing means senses a pre-selected light level.

14. The motor of claim 13 wherein the switching circuit is configured to energize the relay coil means when the photosensing means senses at least the pre-selected light level.

15. The motor of claim 13 wherein the switching circuit is configured to energize the relay coil means when the photosensing means senses no more than the pre-selected light level.