Abstract: The supply, regulation and control of a direct current electrical machine such as a motor or generator having a number of winding sections is controlled by energization of the winding sections by staggered pulses which combine to produce a reasonably constant total winding current, the control being by means of first and second pairs of transistor switches controlled by respective control elements, such as magnetic pick-ups or photoelectric detectors, responsive to the rotation of the machine. Alternatively the machine can be operated with intermittent excitation for low speed traction or starting by supplying appropriately shaped control signals to the control elements connected to the transistor switches.

Abstract: A mixed propulsion system comprising a turbine unit having two output shafts which drive two counter rotating flywheels and, via a reduction gearbox, two generators which generate electricity to drive two electric drive motors the output shafts of which are connected to the wheels of the vehicle. A control system is provided, linked to the accelerator and brake pedal of the vehicle, for controlling the excitation of the field windings of the generators and the motors such that a predetermined excitation pattern is followed. The turbine unit is automatically controlled to run when the speed of the flywheels falls below a lower threshold value and is turned off when the flywheels reach a predetermined maximum threshold speed.