X-ray tube starter

Claim 1

IN AN X-RAY APPARATUS HAVING A ROTATING ANODE TYPE X-RAY TUBE WHEREIN THE ANODE IS ROTATABLY SUPPORTED IN A BEARING AND A STATOR WINDING IS PROVIDED TO INDUCE ROTATION OF THE ANODE IN THE BEARING, THE COMBINATION FOR CONTROLLING OPERATION OF THE ROTATING ANODE, SAID COMBINATION COMPRISING: (A) AN EXPOSURE CONTROL MEANS HAVING ON AND OFF POSITIONS, SAID EXPOSURE CONTROL MEANS IN THE ON POSITION CONNECTING THE STATOR WINDING TO A FIRST VOLTAGE SOURCE; (B) TRANSDUCER MEANS RESPONSIVE TO THE CHARACTERISTIC FREQUENCY OF THE SCREECH OF THE ANODE MOVING IN ITS BEARING AND PRODUCING AN OUTPUT SIGNAL DIRECTLY RELATED TO THE ROTATIONAL SPEED OF THE ANODE; (C) A SAFETY CIRCUIT MEANS CONNECTED TO THE TRANSDUCER MEANS AND RESPONSIVE TO THE OUTPUT SIGNAL THEREOF, SAID SAFETY CIRCUIT MEANS CONNECTING THE X-RAY TUBE TO A SECOND VOLTAGE SOURCE TO BEGIN A RADIOGRAPHIC X-RAY EXPOSURE ONLY WHEN SAID OUTPUT SIGNAL INDICATES THAT THE ANODE IS ROTATING ABOVE A MINIMUM ACCEPTABLE LEVEL; (D) A DYNAMIC BRAKING CIRCUIT MEANS ASSOCIATED WITH SAID STATOR WINDING AND CONNECTGED TO SAID EXPOSURE CONTROL MEANS TO RAPIDLY DECELERATE THE ROTATING ANODE AT THE END OF THE EXPOSURE PERIOD WHEN SAID EXPOSURE CONTROL MEANS IS IN THE OFF POSITION, THE DYNAMIC BRAKING CIRCUIT MEANS BEING CONNECTED TO THE TRANSDUCER MEANS AND BEING RESPONSIVE TO THE OUTPUT SIGNAL OF THE TRANSDUCER DEVICE MEANS TO APPLY DYNAMIC BRAKING UNTIL THE ANODE HAS DECELERATED TO A PRESELECTED ROTATIONAL SPEED AS INDICATED BY SUCH OUTPUT SIGNAL; (E) A FLUOROSCOPY CONTROL CIRCUIT MEANS FUNCTIONING INDEPENDENT OF SAID EXPOSURE CONTROL MEANS FOR CONNECTING SAID STATOR WINDING TO THE FIRST VOLTAGE SOURCE, AND SAID FLUOROSCOPY CONTROL CIRCUIT MEANS BEING CONNECTED TO THE TRANSDUCER MEANS AND BEING RESPONSIVE TO THE OUTPUT SIGNAL OF SAID TRANSDUCER MEANS TO PERIODICALLY CONNECT THE STATOR WINDING TO THE FIRST VOLTAGE SOURCE TO MAINTAIN LOW SPEED ROTATION OF THE ANODE DURING FLUOROSCOPIC EXAMINATIONS.