Auxiliary lighting system for a gaseous discharge lamp

• US 3,873,882 A
• Filed: 10/05/1973
• Issued: 03/25/1975
• Est. Priority Date: 10/05/1973
• Status: Expired due to Term

• Current Assignee: Bernard J. Gershen
• Original Assignee: Bernard J. Gershen
• Inventors: Gershen, Bernard J.
• Primary Examiner(s): Rolinec, R. V.
• Assistant Examiner(s): LaRoche, E. R.
• Application Number:
  US05/403,948
• Time in Patent Office: 536 Days
• Field of Search: 315/88,91,92,119,120,121,127,129,130,131,135,178,182
• US Class Current: 315/92
• CPC Class Codes: H02J 9/02 in which an auxiliary distribution system and its associated lamps are brought into service
• CPC Class Codes: H03K 17/725 for ac voltages or currents H03K17/722, H03K17/735 take precedence

Abstract

An emergency or auxiliary lighting system for a gaseous discharge lamp is provided with an auxiliary lamp controlled by a switch which is biased to remain in a closed position. A control circuit, responsive to the voltage across the gaseous discharge lamp, produces a voltage proportional thereto which is opposed to the biasing control. During any time that the gaseous discharge lamp provides more than a minimum adequate light output, the control circuit voltage becomes greater than the biasing control to open the switch. Also, in the event of a power interruption, the control circuit closes the switch.

Claims

1. An auxilairy lighting system for use with a primary lighting system having a gaseous discharge lamp and a ballast connecting the gaseous discharge lamp to an alternating current source of voltage for igniting and operating said gaseous discharge lamp, said auxiliary lighting system comprising:

a. an auxiliary light source;

b. switch means connected in series with said auxiliary light source and an output from a ballast;

c. said switch means comprising an SCR and a bridge rectifier;

d. biasing means connected in series with said switch means and said auxiliary light source for producing an output voltage acting on said switch means and maintaining said switch means in a conductive condition;

e. said biasing means including a resistor connected between a gate electrode of said SCR and a source of positive voltage; and

f. control means responsive to a voltage across the discharge lamp for producing an output proportional to said lamp voltage and opposing the output voltage of the biasing means;

g. said control means includes a transformer and a rectifier connected across a gaseous discharge lamp for Producing a negative output voltage proportional to the voltage applied to said discharge lamp;

h. said output voltage from the transformer and rectifier being connected to the gate electrode of the SCR;

i. said control means having an output voltage which is greater in magnitude than said output voltage from the biasing means during a period of time when said gaseous discharge lamp is operating at full illumination and said SCR is in a nonconductive condition, and causing said SCR to become conductive in response to application of a starting voltage to said gaseous discharge lamp;

j. said control means also including a filter circuit and a breakdown device connected between the output of the transformer and the rectifier and the gate electrode of the SCR;

k. said breakdown device producing a fixed low voltage after application of a high voltage thereto in response to the application of a starting voltage to the discharge lamp.

2. An auxiliary lighting system as defined in claim 1, in which:

a. the bridge rectifier is connected to the alternating current source of voltage and produces a positive voltage applied at the resistor of the biasing means;

3. An auxiliary lighting system as defined in claim 1, wherein:

a. said transformer has a primary connected across the gaseous discharge lamp and a secondary having ends interconnected at a first terminal;

b. said secondary having an intermediate tap providing a second terminal;

c. said filter circuit comprising capacitors and resistances connected across said first and second terminals of the transformer secondary.

4. An auxiliary lighting system as defined in claim 3, wherein:

a. said breakdown device comprises a silicon unidirectional switch connected in parallel with one of the filter capacitors.

5. An auxiliary lighting system as defined in claim 3, which includes:

a. a limiting resistor serially connected between the gaseous discharge lamp and the primary of said transformer.

6. A lighting system, which comprises:

a. a gaseous discharge lamp;

b. a ballast connnected to said gaseous discharge lamp and to a source of alternating current voltage for igniting and operating said discharge lamp;

c. an auxiliary light source;

d. rectifier means connected across said gaseous discharge lamp;

e. said rectifier means producing an output;

f. reed switch means comprising an electromagnetic coil enclosing a pair of movable contact elements;

g. said electromagnetic coil being connected to the output from said rectifier means in parallel with a filter capacitor;

h. said movable contact elements being connected in series with a limiting resistor between an anode and a gate electrode of a semi-conductor switch;

i. said contact elements when closed supplying a voltage to said gate electrode and causing said semi-conductor switch to become conductive; and

j. permanent magnet means positioned adjacent said electromagnetic coil and acting on the movable contact elements to hold the contacts closed;

k. said electromagnetic coil when energized producing a magnetic field in opposition to the magnetic field of the permanent magnet;

l. said coil and said permanent magnet having a net field holding the contacts in engagement after a power interruption and during a warm-up period of the lamp;

m. said net field permitting the contacts to separate under conditions when the lamp is operating and producing an acceptable level of illumination.