Abstract: Certain embodiments of the invention are directed to a medical fluid injector of the type that uses a motor to drive fluid from a fluid container by receiving electrical energy from a power source. The medical fluid injector has a motor drive control that delivers electrical energy to the motor. The motor drive control measures electrical energy delivered to the motor and computes a pressure value of the fluid delivered based upon the measured electrical energy. This pressure value is computed utilizing a calibrated relationship between the electrical energy delivered to the motor and resulting fluid pressure from the fluid delivered. The control further tracks a time factor over an operative life of the motor and alters the calibrated relationship based upon the time factor.

Abstract: A ground power unit capable of no-break power transfer includes a rectifier for converting power from commercial mains to direct current, a switching circuit, a power transformer, and a pattern generator for controlling the operation of the switching circuit. Voltage and current sensors monitor whether the phase of the ground power unit is leading or lagging the phase of the aircraft power bus at the tinge of power transfer. The frequency and phase of the pattern generator converter is adjusted to bring the two systems into alignment quickly, well before the power transfer operation is completed. The ground power unit limits the power transfer between the two systems to prevent the overloading of either.

Abstract: A solenoid power control circuit provides full power during lifting and reduced power during maintaining a lift condition in a lifting solenoid of an electric arc stud welding gun. During the stud lifting portion of a stud welding process, relatively high power is provided to the lifting solenoid to effect work necessary to accomplish the lift; but after a lifted condition has been achieved, the invention phases back power to reduce the energy dissipated while the stud and the lifting solenoid are maintained in lifted condition. A relaxation oscillator having two different charging time constants that can be selected to provide long or short phase delay is employed for the phase modulation control of lifting solenoid energization.