Fluorescent lamp electrode disconnect arrangement

A rapid start fluorescent lamp system comprising, a plurality of fluorescent lamps each having a pair of electrodes, a ballast for connection to a proper source of voltage, said ballast including a primary winding and a secondary winding, said ballast when connected to said proper source of voltage providing voltage across said lamps, said ballast including a plurality of electrode heater windings connected to said electrodes, at least one of said electrode heater windings comprising a portion of said secondary winding, a plurality of switches, one for each electrode heater winding, each switch connected between its associated electrode heater winding and an associated lamp electrode, and control means connected across said lamps and responsive to said voltage across said lamps when said lamps are on to render each said switch non-conductive, said control means being operable in response to said voltage across said lamps when said lamps are off to render each said switch conductive, voltage for operating at least one of said switches between its non-conductive state and its conductive state being supplied by the electrode heater winding to which said at least one switch is connected.

A fluorescent lamp system comprising, a fluorescent lamp having a pair of electrodes, a ballast for connection to a proper source of voltage, said ballast including a primary winding and a secondary winding, said ballast when connected to said proper source of voltage providing voltage across said lamp, said ballast including a pair of electrode heater windings, at least one of said electrode heater windings comprising a portion of said secondary winding, a pair of semiconductor switches, each connecting one of said electrode heater windings to a respective lamp electrode, and control means connected across said lamp and responsive to said voltage across said lamp when said lamp is off to conduct current, said current rendering each said semiconductor switch conductive, said control means being responsive to said voltage across said lamp when said lamp is on to render each said semiconductor switch non-conductive.

A rapid start fluorescent lamp system comprising, a plurality of fluorescent lamps each having a pair of electrodes, a ballast for connection to a proper source of voltage, said ballast including a primary winding and a secondary winding, said ballast when connected to said proper source of voltage providing voltage across said lamps, said ballast including a plurality of electrode heater windings connected to said electrodes, at least one of said electrode heater windings comprising a part of said secondary winding, a plurality of switches, one for each electrode heater winding, each switch connected between its associated electrode heater winding and an associated electrode, and control means connected across said lamps and responsive to said voltage across said lamps when said lamps are off to conduct current, said current rendering each said switch conductive, said control means being operable in response to said voltage across said lamps when said lamps are on to render each said switch non-conductive.

A rapid start fluorescent lamp system comprising, a plurality of fluorescent lamps each having a pair of electrodes, a ballast for connection to a proper source of voltage, said ballast including a primary winding and a secondary winding, said ballast when connected to said proper source of voltage providing voltage across said lamps, said ballast including a plurality of electrode heater windings connected to said electrodes, at least one of said electrode heater windings comprising a part of said secondary winding and another of said electrode heater windings comprising a part of said primary winding, a semiconductor switch for each electrode heater winding connected between its associated electrode heater winding and an associated lamp electrode, and control means connected across said lamps and responsive to said voltage across said lamps when said lamps are on to render each said semiconductor switch non-conductive, said control means being operable in response to said voltage across said lamps when said lamps are off to render each said switch conductive.