Robert Briggs Boydston

US Patent:

62257579, May 1, 2001

Filed:

May 19, 2000

Appl. No.:

9/574902

Inventors:

William L. Brosius - Brentwood TN
Robert P. Boydston - Madison AL
Daniel Soule - Harlingen TX
Candler A. Willis - Zirconia NC

Assignee:

MagneTek Corp. - Huntsville AL

International Classification:

H05B 3700

US Classification:

315250

Abstract:

A combination electronic ballast designed to operate a metal halide lamp and a high-pressure sodium gas discharge lamp is disclosed. The ballast includes a primary and secondary coil coupled to a magnetic core. The primary is adapted to be connected to an ac power source and the secondary is adapted to be connected to a metal halide lamp and a high-pressure sodium lamp. The primary and secondary coils are connected together using a capacitance circuit including two capacitors and a switch. The capacitance circuit is designed to connect both of the capacitors between the primary and secondary coil when a high pressure sodium lamp is connected to the ballast and to connect only one of the capacitors in parallel when a metal halide lamp is connected to the ballast. In an alternative embodiment, the primary is adapted to be connected to one of four different ac power sources.