Wireless emergency lighting unit

• US 4,682,078 A
• Filed: 01/28/1985
• Issued: 07/21/1987
• Est. Priority Date: 01/28/1985
• Status: Expired due to Fees

• Current Assignee: Radiant Illumination Incorporated
• Original Assignee: Radiant Illumination Incorporated
• Inventors: Pascalide, Chiriac
• Primary Examiner(s): Chatmon, Saxfield
• Application Number:
  US06/695,277
• Time in Patent Office: 904 Days
• Field of Search: 315/86, 315/87, 307/64, 307/66, 362/20, 362/183
• US Class Current: 315/86
• CPC Class Codes: H02J 9/065 for lighting purposes

Abstract

A circuit is disclosed herein for use in series with a fluorescent lamp and a conventional ballast for supplying operating current to the lamp when the main line source of power has been interrupted. The circuit includes a sensor for detecting the lamp current and utilizes the lamp current for charging a storage battery via a battery charger. An inverter ballast circuit is normally maintained in an "OFF" condition by the sensor and is responsive to the sensor when the power source to the lamp has been interrupted so that the power from the battery is applied to the inverter ballast to turn it to the "ON" condition. Conduction of the inverter ballast circuit provides AC voltage to energize the fluorescent lamp through the conventional ballast.

Claims

1. An externally wireless emergency power unit for use with a standard fluorescent lamp of the type mountable in a conventional fixture incorporating conventional ballast means and operable when powered by an AC line through said conventional ballast means, said lamp being illuminated when power from said AC line is operatively connected to first and second terminals on said fixture, said emergency power unit being operable to illuminate said lamp when the AC line voltage falls below a predetermined level, said unit comprising:

a unitized elongated housing and circuit means wholly enclosed within said housing;

said housing comprising connectors carried on its opposite ends, one of said connectors being adapted to be inserted in one socket of said conventinal fixture and the other of said connectors being adapted to engage with a connector at one end of said standard fluorescent lamp, the connector at the other end of which is adapted to engage another socket of said fixture;

said circuit means comprising a pair of leads adapted to be connected through said one connector from said ballast means to apply a voltage derived from said AC line to a first winding of a heater voltage transformer within said emergency unit, a second winding of said transformer being connected through said other connector to said one end of said lamp;

a rechargable storage battery;

a battery charging circuit for charging said battery;

an inverter circuit including a transistor having a collector-emitter circuit energizable from said battery;

sensor means for sensing said voltage across said pair of leads to determine when said voltage falls below a predetermined level; and

switch means, including a switch contact connecting the emitter of said collector-emitter circuit and one side of said battery, responsive to said sensor when said voltage is at or above said level, for connecting said battery charging circuit to derive charging current from current flowing through said lamp and disabling said inverter circuit by opening said switch contact and, when said voltage falls below said level, for disabling said charging circuit and connecting said battery across the collector-emitter circuit of said inverter circuit by closing said switch contact and connecting the output voltage from said inverter circuit betwen said other connector connected to said one end of said fluorescent lamp and, through one of said leads, said one connector and said ballast means, to the other end of said lamp, whereby said lamp is illuminated from said battery when said voltage falls below said level, said sensor means comprising a rectifier bridge having its input terminals connected across said pair of leads and having its output terminals connected across a single relay coil, said single relay coil controlling said switch means.