Method and apparatus for starting high intensity discharge lamps

摘要

A high pressure sodium lamp, which includes a discharge tube enclosing xenon at pressures in excess of 300 torr, is reliably started by the combination of an igniter, a conductor wrapped around the discharge tube, and a switching circuit. The igniter provides periodic pulses of 2500 to 4000 volts with a duration of at least one microsecond. The switching circuit provides a high voltage pulse having an amplitude about equal to the amplitude of the periodic pulses and a duration much greater than the duration of the periodic pulses. The conductor intensifies the electric field within the discharge tube. A conventional lamp ballast provides ac power during starting and normal operation.