Discharge lamp operating circuit
AssigneeGeneral Electric Company
InventorDon Morais
Life of this patent
Estimating the term…
Abstract
Increased color temperature of high pressure sodium vapor discharge lamps is provided by improved operating circuit for applying pulsed direct current to the lamp. The circuit includes a direct current ballast circuit having low ripple factor and a pulsing circuit comprising a controlled thyristor switch which operates to apply DC pulses to the lamp at a predetermined repetition rate and duty cycle. The described circuit provides for gradual increase in power applied to the discharge lamp during the starting interval and thereby avoids instability of lamp operation during that stage.
Claims11
A lamp operating circuit comprising, in combination, DC supply means comprising input terminals for connection to an AC current source, current limiting reactance means comprising a first induction coil connected to said input terminals, an auxiliary induction coil inductively coupled to said first induction coil, first rectifier means connected to the output of said first induction coil, and second rectifier means connected to the output of said auxiliary induction coil, and a DC pulsing circuit connected to said first and second rectifier means and comprising a first inductor, unidirectional controlled switch means, and a capacitor connected in series with each other across said DC supply means, means for serially connecting a gaseous discharge lamp in said DC pulsing circuit, a second inductor of higher inductance than said first inductor connected across said capacitor and forming a discharge loop therewith, and control means connected to said unidirectional controlled switch means for intermittently operating the same at predetermined intervals, whereby DC pulses are applied to the gaseous discharge lamp for operation thereof and operation of the lamp during the starting interval is stabilized.
A lamp operating circuit comprising, in combination, DC supply means comprising a source of AC current, current limiting reactance means comprising a first induction coil connected to said AC source, an auxiliary induction coil inductively coupled to said first induction coil, first rectifier means connected to the output of said first induction coil, second rectifier means connected to the output of said auxiliary induction coil, and a first capacitor connected between said auxiliary induction coil and said second rectifier means, and a DC pulsing circuit connected to said DC supply means comprising a first inductor, unidirectional controlled switch means, a second capacitor and a gaseous discharge lamp connected in series with each other across said DC supply means, a second inductor of higher inductance than said first inductor connected across said second capacitor and forming a discharge loop therewith, a diode arranged in series with said second inductor across said second capacitor, and control means connected to said unidirectional controlled switch means for intermittently operating the same at predetermined intervals, whereby DC pulses are applied to said gaseous discharge lamp for operation thereof and operation of said lamp during the starting interval is stabilized.
Dependencies are inferred from the claim text.