Abstract: A rotor speed adjustment circuit (60) reduces the rotational speed of an anode (32) of an x-ray tube (14) in a diagnostic apparatus (10). An AC current (64) from an AC current source (54) is applied to one stator winding (52). A parallel connected diode (70) and resistor (72) are connected between the current source and a second stator winding (50) to cause an effective DC magnetic braking component (66b) which reduces the rotational speed of the anode and an associated rotor (42). By selectively adjusting the resistor (72), the size of the DC magnetic braking component, hence the amount of effective drag is selectively adjustable to adjust the anode rotation speed.

Abstract: An x-ray diagnostics generator which includes a rotating anode x-ray tube includes circuitry for setting the speed of rotation of the anode dependent on exposure parameters. At particular rotational speeds, the motor bearing for the rotating anode is subject to mechanical resonances, causing vibrations which can damage the bearing. A vibration detector is provided in mechanical contact with the x-ray tube, and when vibrations due to such mechanical resonances are sensed, a signal is provided from the detector to a processor which automatically slightly alters the rotational speed.

Abstract: An X-ray tube support apparatus includes: an X-ray tube support mechanism for supporting an X-ray tube to be vertically extendible/movable; a guide unit, having moving paths which allow movement in two-dimensional directions parallel to a ceiling surface, for supporting the X-ray tube support mechanism, and guiding the X-ray tube to a central position of one photographing table; a plurality of position sensors, arranged in a vertical moving path of the X-ray tube support mechanism, and two-dimensional moving paths to the central position of the photographing table, for detecting vertical and two-dimensional moving positions of the X-ray tube support mechanism; a plurality of fixing units, arranged in the two-dimensional moving paths of the guide unit and the vertical moving path of the X-ray tube support mechanism, for fixing the X-ray tube support mechanism at each moving position; and a determination unit for storing position data in accordance with the central position of the photographing table and a set

Abstract: An x-ray tube (10) imaging system, such as a computed tomography scanner, includes a cathode (40) for generating a stream of electrons. A rotating anode (42) is placed in a path of the electron stream and generates x-rays as a result of collisions therewith. An induction rotor (44) causes rotation of the anode as a result of electromagnetic interaction with a stator (48) comprised of two windings: a run winding (50) and a phase winding (52). The run winding and the phase winding are connected to three nodes (54, 58, 60), one of which is common to both. The three nodes are actively driven with run, common, and phase signals, respectively. Actively driving the three nodes increases bus drive voltage over 40% over that achieved by half-bridge drives.

Abstract: A boost circuit for providing rapid acceleration of anode rotating motors for X-Ray tubes features provision for supplying to the motor for a limited period of time a relatively high power AC excitation at a frequency well above that corresponding to the rotation speed to be maintained during exposure. Once proper operating speed is reached, the motor power supply voltage is reduced to a safe power level with respect to the stator windings, and the frequency is reduced to correspond to the desired running speed during exposure. In the preferred embodiment the changeover is governed by means of an empirically adjusted timer; however, changeover may be controlled by a variety of means.