Patent ID: 7656067

Claim:
An electric machine operable as an alternator, the machine comprising: a rotating magnetic rotor assembly; and a stationary stator assembly mounted adjacent the rotor assembly such that an annular rotor air gap separates the rotor assembly from the stator assembly, the stator assembly including a plurality of lengthwise extending slots on a cylindrical surface of the stator assembly and opposed to the annular rotor air gap, the stator assembly further including at least one electrical winding disposed in at least one of the lengthwise extending slots defined in the stator assembly, the at least one electrical winding being electrically connected to a machine output adapted to deliver generated output electricity from the machine, the slots having slot gaps on the stator surface thus defining teeth members, the teeth members being disposed between the at least one winding and the rotor, the slot gaps having a circumferential width Gg, a radial height Hg and an axial length Lg, defining an area of the gap as a function of Hg and Lg, wherein, in use, movement of the rotor assembly induces a first alternating voltage and current in the at least one winding, characterized in that said slot gap is sized by selecting given values of circumferential width Gg or area of the gap so as to have an associated leakage self-inductance such that, in use, a leakage magnetic flux flows across said slot gaps and around the at least one winding in order to induce in said winding a counter-voltage of a given magnitude in response to said induced alternating current in said winding, thereby limiting a maximum output current in the at least one winding to a pre-selected value.