| 摘要 |
PURPOSE:To increase life of an X-ray tube rotating part by comparing actual load of an X-ray tube with an allowable load and driving an anode in normal speed rotation when an input is low, and in high speed rotation when an input exceeds allowable value. CONSTITUTION:Tube voltage and tube current which are predetermined are multiplied with a multiplier 1 to output as an actual load. The actual load is compared with an allowable load of an allowable load generator 2 which inputs predetermined image pick-up time with a comparator 3. By this output, contacts 12 and 13 are switched to connect a normal speed oscillator 5 or a high speed oscillator 6 to an anode driving circuit 7 to drive an anode 9 of an X-ray tube 8. When an actual load is lower than an allowable load in normal speed rotation, the anode is drived in normal speed rotation, and when an actual load exceeds an allowable load, it is driven in high speed rotation. Therefore, life of a rotating part of the X-ray tube 8 is increased and image pick-up in short starting time is made possible. |
