Method for starting and operating a preheat type fluorescent lamp
First Claim
1. A method for starting and operating a preheat type fluorescent lamp in which the lamp has a first lower impedance starting mode providing current flow through at least one lamp filament operated in series with a starting switch means from an electrical power source, a second higher impedance operating mode providing current flow through the lamp with said starting switch open, and a series saturable magnetically permeable core-and coil inductor for limiting current flow through the lamp in which the improvement comprises:
- passing current from the starting switch means through said coil-core inductor at a level to provide(a) operation of the magnetically permeable core of the core-and-coil inductor in a substantially saturated condition when the lamp is in the lower impedance starting mode; and
(b) operation of the magnetically permeable core of the core-and-coil inductor in a non-saturated condition when the lamp is in the higher impedance operating mode.
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Abstract
A method for starting and operating a preheat type fluorescent lamp includes a source of alternating current, a fluorescent lamp having a low impedance starting mode wherein current passes through one or more starting filaments and a high impedance operating mode wherein current passes through the length of the lamp, a starting switch directing current through the starting filaments in the lamp starting mode, and an inductor ballast having a magnetically permeable core operating in a saturated condition when the lamp is in the low impedance starting mode and in a non-saturated condition when the lamp is in the high impedance operating mode.
13 Citations
7 Claims
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1. A method for starting and operating a preheat type fluorescent lamp in which the lamp has a first lower impedance starting mode providing current flow through at least one lamp filament operated in series with a starting switch means from an electrical power source, a second higher impedance operating mode providing current flow through the lamp with said starting switch open, and a series saturable magnetically permeable core-and coil inductor for limiting current flow through the lamp in which the improvement comprises:
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passing current from the starting switch means through said coil-core inductor at a level to provide (a) operation of the magnetically permeable core of the core-and-coil inductor in a substantially saturated condition when the lamp is in the lower impedance starting mode; and (b) operation of the magnetically permeable core of the core-and-coil inductor in a non-saturated condition when the lamp is in the higher impedance operating mode. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification