Showing papers on "Voltage sag published in 1983"

Plywheel-powered mobile X-ray apparatus

Abstract: A mobile X-ray apparatus (20) is disclosed which incorporates a power supply (22) in which the energy for operation of the X-ray tube (21) is supplied from a flywheel (50) coupled to an electrical machine (24) which functions as both a motor and generator. In the motor mode of operation, a controller (21) provides power to the machine (24) to operate it as a motor and drive the flywheel up to a desired operating speed. Upon request of the operator to initiate an exposure, the controller power is disconnected from the machine and the power terminals (32) of the machine (24) are connected to a transformer and rectifier (27) which increases the generated voltage and rectifies it to provide the high voltage across the X-ray tube (21) required for proper exposures. The controller (31) provides a first selected level of current to the control winding (77) of the machine (24) required during the motor mode for proper motor operation, and provides a higher selected current level to the control winding (77 ) during generator operation. The controller also provides a boost in the control winding current as the machine (24) begins to supply power during an exposure to compensate for the voltage sag that ordinarily occurs upon loading of the machine to thereby maintain the output voltage substantially constant.