Saturable reactor device for operating a discharge lamp
AssigneeU.S. Philips Corporation
InventorJacob Rottier
Life of this patent
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Abstract
A device for starting and operating a discharge lamp, in particular a low pressure sodium vapor lamp. The device comprises two input terminals connected by means of a coil and the primary winding of an auto-transformer with the lamp connected in series with a capacitor between the ends of the transformer secondary winding. In the operating condition of the lamp the core of the transformer becomes saturated. The lamp is shunted by an electronic starter which assists, in the operating condition of the lamp, in the restart of the lamp during each half cycle of the AC electric supply.
Claims9
A device for starting and operating a low pressure sodium vapor discharge lamp comprising, two input terminals for connection to a source of AC voltage, first and second inductor coils, means connecting said first and second coils in a series circuit across said two input terminals, a capacitor, means connecting said discharge lamp and the capacitor in a series circuit across two terminals of the second coil, said first and second coils being designed so that the first coil does not saturate in the operating condition of the lamp, whereas the second coil does saturate during operation of the lamp, and means connecting a starter including a semiconductor switch in shunt with the discharge lamp.
A starting and operating circuit for an electric discharge lamp comprising, a pair of input terminals for connection to a source of AC voltage, a ballast coil, a saturable reactor coil, means connecting said ballast coil and said saturable reactor coil in a series circuit across said input terminals, a capacitor, means connecting said discharge lamp and said capacitor in a series circuit across a part of said saturable reactor coil, said ballast coil being designed so that it does not saturate at the lamp operating current, said saturable reactor coil being saturable at the lamp operating current thereby to deform the lamp current waveform so it exhibits a rapid decline just prior to its zero crossing, and means connecting a semiconductor switch in shunt with the discharge lamp for generating a high voltage pulse to start the lamp.
Dependencies are inferred from the claim text.