Abstract: An electrical machine, such as an induction motor, comprises a stator having a plurality of conductive windings spaced around an axis of rotation, a rotor rotatable about the axis of rotation in response to the flow of current through the stator windings, and a plurality of switching assemblies provided at circumferentially spaced locations around the stator. Each switching assembly is electrically connected between an end of at least one of the windings and a power supply busbar ring assembly comprising at least one conductor. The busbar assembly connects the electrical supply to one or more of the switching assemblies, each of the switching assemblies being effective to selectively control the supply of current to at least one of the windings.