Patent ID: 6867561

Claim:
An electrical machine comprising a rotor without windings, a stator having an armature winding and a field winding for generating a magnetomotive force in a direction extending transversely of the magnetomotive force generated by the armature winding and circuit means for controlling the current in the armature winding such that periods in which the magnetomotive force in one direction is associated with a first current pulse alternate with periods in which the magnetomotive force in the opposite direction is associated with a second current pulse, the circuit means incorporating principal terminals and capacitance means including a first capacitance coupled between one of the principal terminals and a circuit point intermediate the field winding and the armature winding, characterized in that the capacitance means further Includes a second capacitance across the principal terminals, the first capacitance having a capacitance value such that the voltage at said circuit point is capable of rising above the voltage across the second capacitance to boost the voltage initializing the armature current at the start of each current pulse.