Outdoor lighting control apparatus

• US 5,325,023 A
• Filed: 06/11/1993
• Issued: 06/28/1994
• Est. Priority Date: 03/03/1993
• Status: Expired due to Fees

• Current Assignee: Bankers Trust Company
• Original Assignee: Pacific Scientific Company Incorporated (Regal Rexnord Corp.)
• Inventors: Martich, Mark E.
• Primary Examiner(s): KWON, JOHN
• Application Number:
  US08/075,993
• Time in Patent Office: 382 Days
• Field of Search: 315/159, 315/158, 315/156, 250/205
• US Class Current: 315/159
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An outdoor lighting control circuit for operation with a variable input voltage and with an electrical lamp, the circuit including a first resistive impedance element for protecting the circuit from excessive current, and a photosensitive element for presenting a first impedance when actuated by light and a different second impedance in the absence of light. The photosensitive element is electrically in series with the first resistive impedance element, to form a first series combination. An electrical relay in the circuit has contacts for selectively connecting the load to the input voltage and has a relay coil. A second resistive impedance element of the circuit controls the current in the relay coil. The second resistive impedance element is electrically in parallel with the relay coil, to form a first parallel combination. The first parallel combination is electrically in series with the first series combination, all elements being between the input terminals that receive the operating voltage.

Claims

1. An outdoor lighting control circuit for operation with a variable input voltage ranging between a selected minimum voltage and a selected maximum voltage and with an electrical load, said circuit comprising

A. first resistive impedance means,

B. photosensitive means electrically in series with said first resistive impedance means, and having a first electrical impedance in the presence of light and a different second impedance in the absence of light,

C. an electrical relay having contacts for connection with said electrical load and having a relay coil,

D. second resistive impedance means electrically in parallel with said electrical relay coil, and

E. said parallel combination of said second resistive impedance means and said relay coil being electrically in series with said series combination of said photosensitive means and said first resistive impedance means.

2. A circuit according to claim 1 wherein said first resistive impedance means has an impedance value for protecting said electrical relay from overcurrents when said variable input voltage is at said selected maximum voltage.

3. A circuit according to claim 1 wherein said first resistive impedance means comprises a first fixed resistor.

4. A circuit according to claim 1 wherein said second resistive impedance means comprises a series combination of a varistor and a second fixed resistor.

5. A circuit according to claim 4 wherein said second fixed resistor has an impedance value for protecting said varistor from overcurrent.

6. A circuit according to claim 1 wherein said second resistive impedance means comprises a varistor.

7. A circuit according to claim 1 wherein said photosensitive means develops relatively low impedance in response to incident ambient light and develops a relatively high impedance in the absence of incident ambient light.

8. In an outdoor lighting control circuit having input terminals for receiving an input voltage variable within a selected range and having output terminals for connection to an electrical load including a lamp device, said control circuit having a resistor element and a photosensitive element and a relay coil identically in series between said input terminals and having contacts of the relay arranged for connection to the lamp, the improvement comprising

a nonlinear voltage dependent resistor element, the resistance of which is inversely related to the applied voltage, connected electrically in parallel with said relay coil, so that the parallel combination of the voltage dependent resistor and of said relay coil are in series with said resistor element and said photosensitive element.