Resonant electrical machine

An electrical induction motor, for example a parallel resonance induction motor 300, has a stator 330 including windings 331 arranged in series with capacitors 332. A further set of windings 333 is arranged in parallel with the capacitors. The parallel resonance induction machine may include switches 340a-c which selectively disconnect the windings from a power source of the stator. Accordingly, the parallel resonance induction machine may revert to operation as a traditional resonant electrical machine by opening the switches, and may operate as a parallel resonance induction machine by closing the switches. A controller may be provided to actuate the switches at one or more predetermined operating frequencies of the electrical power supply. A controller may be configured to control a driving frequency of the electrical power supply to prevent the driving frequency being within a predetermined frequency range.