Fluorescent lamp ballast and thermal protective means therefor

Abstract

Abstract BALLAST CONTROL FOR ELECTRON DISCHARGE TUBES, SUCH AS FLUORESCENT LAMPS, IN WHICH THE LAMPS ARE CONNECTED TO THE SECONDARY OF A TRANSFORMER HAVING A PRIMARY WINDING INCORPORATING BLOCKING OSCILLATOR MEANS IN WHICH A SINGLE TRANSISTOR HAS ITS OUTPUT CIRCUIT CONNECTED THROUGH ONE PORTION OF THE PRIMARY WINDING TO THE TERMINALS OF A DC SOURCE, AND ITS INPUT CIRCUIT CONNECTED THROUGH ANOTHER PORTION OF THE TRANSFORMER PRIMARY WINDING TO THE TERMINALS OF THE DC SOURCE, THE INPUT CIRCUIT BEING PROVIDED WITH RESISTOR MEANS AND CAPACITOR MEANS WHICH COACT WITH THE PRIMARY WINDING PORTION OF THE INPUT CIRCUIT IN A MANNER TO EFFECT A TUNED RC NETWORK AND AN LC NETWORK HAVING A RELATIVELY HIGH FREQUENCY OF OSCILLATION ACTING TO ALTERNATELY BIAS THE TRANSISTOR INTO CONDUCTING AND NONCONDUCTING STATES FOR UNIFORMLY PULSING CURRENT FLOW FROM THE DC SOURCE TO THE PRIMARY WINDING, AND IN WHICH THERMAL SENSING PROTECTIVE MEANS OPERATES TO AUTOMATICALLY CONTROL THE OPERATION AND NONOPERATION OF THE OSCILLATOR MEANS AND PREVENT THE BALLAST FROM REACHING DANGEROUSLY HIGH TEMPERATURES WHICH COULD RESULT IN THE CREATION OF EQUIPMENT HAZARDS.

Inventors

• 👤 Jerry J Silvers

Bibliographic Details