A rotor for a synchronous reluctance machine wherein a torque ripple behaviour of the machine is optimized by altering the geometry of insulating barriers of the rotor. A q-axis pitch angle is used as a design variable instead of setting its value equal to the rest of the rotor slot pitches or binding its value to the stator slot pitch. The resulting rotor has a non-regular slot pitch across the q-axis and substantially regular slot pitch otherwise. Synchronous reluctance machines that employ rotor discs and rotor assemblies in accordance with the present invention may exhibit low torque ripple without sacrificing high torque values.