Sinusoidal Alternating Current Ballast For Fluorescent Emergency Lighting

• US 20110043041A1
• Filed: 08/18/2010
• Published: 02/24/2011
• Est. Priority Date: 08/18/2009
• Status: Abandoned Application

• Current Assignee: Cooper Technologies Company (Eaton Corporation PLC.)
• Original Assignee: Cooper Technologies Company (Eaton Corporation PLC.)
• Inventors: Mangiaracina, Anthony, Porter, Kevin
• Application Number:
  US12/859,023
• Publication Number:
  US 20110043041A1
• Time in Patent Office: Days
• US Class Current: 307/66
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/02 in which an auxiliary distribution system and its associated lamps are brought into service
• CPC Class Codes: H05B 41/2985 against abnormal lamp operating conditions

Abstract

A ballast for a lamp has a battery that provides direct current in response to a loss of power. The ballast has a conversion circuit that is configured to receive the direct current from the battery and convert it into alternating current that is provided to a lamp. The alternating current is substantially sinusoidal, and has a current crest factor of 1.7 or less. The conversion circuit can use a push-pull topology. The ballast can also include a cathode-heating circuit for pre-heating a cathode associated with the lamp. The cathode-heating circuit pre-heats a cathode of the lamp by increasing the current output of the conversion circuit. The ballast can also include circuitry for converting mains power to power appropriate to illuminate the lamp.

Claims

1. A ballast for a luminaire, comprising:

a battery that provides direct current in response to a loss of mains power to the luminaire;

a conversion circuit, wherein the circuit receives the direct current from the battery, converts the direct current into substantially sinusoidal alternating current, and provides the alternating current to a lamp in the luminaire.

2. The ballast of claim 1, wherein the substantially sinusoidal alternating current has a current crest factor of 1.7 or less.

3. The ballast of claim 1, wherein the loss of power comprises a loss of a mains power.

4. The ballast of claim 1, wherein the conversion circuit comprises a push-pull topology.

5. The ballast of claim 1, further comprising a cathode-heating circuit configured to pre-heat a cathode of the lamp.

7. The ballast of claim 1, wherein the lamp is a fluorescent lamp.

8. The ballast of claim 1, further comprising circuitry for converting mains power to power appropriate to illuminate the lamp.

6. The ballast of claim 6, wherein the cathode-heating circuit increases the current output of the conversion circuit.

9. A method for providing emergency power to a lamp, comprising:

determining whether mains power has been interrupted;

providing direct current to a conversion circuit in response to a determination that mains power has been interrupted;

converting the direct current to alternating current, wherein the alternating current is substantially sinusoidal; and

providing the alternating current to the lamp.

10. The method of claim 9, wherein the alternating current comprises a current crest factor of 1.7 or less.

11. The method of claim 9, wherein the lamp comprises a fluorescent lamp.

12. The method of claim 9, wherein the conversion circuit comprises a push-pull topology.

13. The method of claim 9, wherein the direct current is supplied by a battery electrically coupled to the conversion circuit.

14. The method of claim 9, further comprising the step of heating a cathode of the lamp.

15. The method of claim 14, wherein heating the cathode comprises increasing the current to a cathode of the lamp.

16. The method of claim 9, further comprising converting mains power to power appropriate for lighting the lamp in response to determining that mains power has not been interrupted.

18. The circuit of claim 16, wherein the conversion circuit comprises a push-pull topology.

19. The circuit of claim 16, further comprising a cathode heating circuit for pre-heating a cathode of the lamp.

20. The circuit of claim 16, further comprising a ballast for converting mains power to current appropriate for powering a fluorescent lamp.

17. A circuit for providing current to a fluorescent lamp, comprising:

a battery configured to deliver direct current in response to an interruption in mains power; and

a conversion circuit configured to convert the direct current to alternating current, wherein the alternating current comprises a substantially sinusoidal waveform having a current crest factor of 1.7 or less, and to provide the alternating current to a fluorescent lamp.